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Kumari M, Checker VG, Kathpalia R, Srivastava V, Singh IK, Singh A. Metabolic engineering for enhanced terpenoid production: Leveraging new horizons with an old technique. PLANT PHYSIOLOGY AND BIOCHEMISTRY : PPB 2024; 210:108511. [PMID: 38593484 DOI: 10.1016/j.plaphy.2024.108511] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/07/2023] [Revised: 02/06/2024] [Accepted: 03/06/2024] [Indexed: 04/11/2024]
Abstract
Terpenoids are a vast class of plant specialized metabolites (PSMs) manufactured by plants and are involved in their interactions with environment. In addition, they add health benefits to human nutrition and are widely used as pharmaceutically active compounds. However, native plants produce a limited amount of terpenes restricting metabolite yield of terpene-related metabolites. Exponential growth in the plant metabolome data and the requirement of alternative approaches for producing the desired amount of terpenoids, has redirected plant biotechnology research to plant metabolic engineering, which requires in-depth knowledge and precise expertise about dynamic plant metabolic pathways and cellular physiology. Metabolic engineering is an assuring tool for enhancing the concentration of terpenes by adopting specific strategies such as overexpression of the key genes associated with the biosynthesis of targeted metabolites, controlling the modulation of transcription factors, downregulation of competitive pathways (RNAi), co-expression of the biosynthetic pathway genes in heterologous system and other combinatorial approaches. Microorganisms, fast-growing host plants (such as Nicotiana benthamiana), and cell suspension/callus cultures have provided better means for producing valuable terpenoids. Manipulation in the biosynthetic pathways responsible for synthesis of terpenoids can provide opportunities to enhance the content of desired terpenoids and open up new avenues to enhance their production. This review deliberates the worth of metabolic engineering in medicinal plants to resolve issues associated with terpenoid production at a commercial scale. However, to bring the revolution through metabolic engineering, further implementation of genome editing, elucidation of metabolic pathways using omics approaches, system biology approaches, and synthetic biology tactics are essentially needed.
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Affiliation(s)
- Megha Kumari
- Department of Plant Molecular Biology, University of Delhi South Campus, Benito Juarez Road, Dhaula Kuan, New Delhi, 110021, India; Department of Botany, Hansraj College, University of Delhi, Delhi, 110007, India
| | | | - Renu Kathpalia
- Department of Botany, Kirori Mal College, University of Delhi, Delhi, 110007, India
| | - Vikas Srivastava
- Department of Botany, School of Life Sciences, Central University of Jammu, Samba, 181143, India
| | - Indrakant Kumar Singh
- Molecular Biology Research Lab, Department of Zoology, Deshbandhu College, University of Delhi, Kalkaji, New Delhi, 110019, India
| | - Archana Singh
- Department of Plant Molecular Biology, University of Delhi South Campus, Benito Juarez Road, Dhaula Kuan, New Delhi, 110021, India; Department of Botany, Hansraj College, University of Delhi, Delhi, 110007, India; Delhi School of Climate Change and Sustainability, Institution of Eminence, Maharishi Karnad Bhawan, University of Delhi, Delhi, India.
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Arévalo S, Pérez Rico D, Abarca D, Dijkhuizen LW, Sarasa-Buisan C, Lindblad P, Flores E, Nierzwicki-Bauer S, Schluepmann H. Genome Engineering by RNA-Guided Transposition for Anabaena sp. PCC 7120. ACS Synth Biol 2024; 13:901-912. [PMID: 38445989 PMCID: PMC10949235 DOI: 10.1021/acssynbio.3c00583] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/15/2023] [Revised: 01/30/2024] [Accepted: 02/16/2024] [Indexed: 03/07/2024]
Abstract
In genome engineering, the integration of incoming DNA has been dependent on enzymes produced by dividing cells, which has been a bottleneck toward increasing DNA insertion frequencies and accuracy. Recently, RNA-guided transposition with CRISPR-associated transposase (CAST) was reported as highly effective and specific in Escherichia coli. Here, we developed Golden Gate vectors to test CAST in filamentous cyanobacteria and to show that it is effective in Anabaena sp. strain PCC 7120. The comparatively large plasmids containing CAST and the engineered transposon were successfully transferred into Anabaena via conjugation using either suicide or replicative plasmids. Single guide (sg) RNA encoding the leading but not the reverse complement strand of the target were effective with the protospacer-associated motif (PAM) sequence included in the sgRNA. In four out of six cases analyzed over two distinct target loci, the insertion site was exactly 63 bases after the PAM. CAST on a replicating plasmid was toxic, which could be used to cure the plasmid. In all six cases analyzed, only the transposon cargo defined by the sequence ranging from left and right elements was inserted at the target loci; therefore, RNA-guided transposition resulted from cut and paste. No endogenous transposons were remobilized by exposure to CAST enzymes. This work is foundational for genome editing by RNA-guided transposition in filamentous cyanobacteria, whether in culture or in complex communities.
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Affiliation(s)
- Sergio Arévalo
- Biology
Department, Utrecht University, Padualaan 8, 3584 CH Utrecht, The Netherlands
- Microbial
Chemistry, Department of Chemistry-Ångström Laboratory, Uppsala University, Lägerhyddsvägen 1, 751
20 Uppsala, Sweden
- Instituto
de Bioquímica Vegetal y Fotosíntesis, CSIC and Universidad
de Sevilla, Avenida Americo Vespucio 49, Sevilla 41092, Spain
- Department
of Biological Sciences, Rensselaer Polytechnic
Institute, 110 Eighth
Street, Troy, New York 12180-3590, United
States
| | - Daniel Pérez Rico
- Biology
Department, Utrecht University, Padualaan 8, 3584 CH Utrecht, The Netherlands
| | - Dolores Abarca
- Biology
Department, Utrecht University, Padualaan 8, 3584 CH Utrecht, The Netherlands
| | - Laura W. Dijkhuizen
- Biology
Department, Utrecht University, Padualaan 8, 3584 CH Utrecht, The Netherlands
| | - Cristina Sarasa-Buisan
- Instituto
de Bioquímica Vegetal y Fotosíntesis, CSIC and Universidad
de Sevilla, Avenida Americo Vespucio 49, Sevilla 41092, Spain
| | - Peter Lindblad
- Microbial
Chemistry, Department of Chemistry-Ångström Laboratory, Uppsala University, Lägerhyddsvägen 1, 751
20 Uppsala, Sweden
| | - Enrique Flores
- Instituto
de Bioquímica Vegetal y Fotosíntesis, CSIC and Universidad
de Sevilla, Avenida Americo Vespucio 49, Sevilla 41092, Spain
| | - Sandra Nierzwicki-Bauer
- Department
of Biological Sciences, Rensselaer Polytechnic
Institute, 110 Eighth
Street, Troy, New York 12180-3590, United
States
| | - Henriette Schluepmann
- Biology
Department, Utrecht University, Padualaan 8, 3584 CH Utrecht, The Netherlands
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Kugler A, Stensjö K. Machine learning predicts system-wide metabolic flux control in cyanobacteria. Metab Eng 2024; 82:171-182. [PMID: 38395194 DOI: 10.1016/j.ymben.2024.02.013] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/24/2023] [Revised: 02/14/2024] [Accepted: 02/20/2024] [Indexed: 02/25/2024]
Abstract
Metabolic fluxes and their control mechanisms are fundamental in cellular metabolism, offering insights for the study of biological systems and biotechnological applications. However, quantitative and predictive understanding of controlling biochemical reactions in microbial cell factories, especially at the system level, is limited. In this work, we present ARCTICA, a computational framework that integrates constraint-based modelling with machine learning tools to address this challenge. Using the model cyanobacterium Synechocystis sp. PCC 6803 as chassis, we demonstrate that ARCTICA effectively simulates global-scale metabolic flux control. Key findings are that (i) the photosynthetic bioproduction is mainly governed by enzymes within the Calvin-Benson-Bassham (CBB) cycle, rather than by those involve in the biosynthesis of the end-product, (ii) the catalytic capacity of the CBB cycle limits the photosynthetic activity and downstream pathways and (iii) ribulose-1,5-bisphosphate carboxylase/oxygenase (RuBisCO) is a major, but not the most, limiting step within the CBB cycle. Predicted metabolic reactions qualitatively align with prior experimental observations, validating our modelling approach. ARCTICA serves as a valuable pipeline for understanding cellular physiology and predicting rate-limiting steps in genome-scale metabolic networks, and thus provides guidance for bioengineering of cyanobacteria.
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Affiliation(s)
- Amit Kugler
- Microbial Chemistry, Department of Chemistry-Ångström Laboratory, Uppsala University, Box 523, SE-751 20, Uppsala, Sweden
| | - Karin Stensjö
- Microbial Chemistry, Department of Chemistry-Ångström Laboratory, Uppsala University, Box 523, SE-751 20, Uppsala, Sweden.
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Turunen O, Saleem T, Kurkela J, Kallio P, Tyystjärvi T. Engineering RNA polymerase to construct biotechnological host strains of cyanobacteria. PHYSIOLOGIA PLANTARUM 2024; 176:e14263. [PMID: 38528669 DOI: 10.1111/ppl.14263] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/01/2023] [Revised: 03/06/2024] [Accepted: 03/08/2024] [Indexed: 03/27/2024]
Abstract
Application of cyanobacteria for bioproduction, bioremediation and biotransformation is being increasingly explored. Photoautotrophs are carbon-negative by default, offering a direct pathway to reducing emissions in production systems. More robust and versatile host strains are needed for constructing production strains that would function as efficient and carbon-neutral cyanofactories. We have tested if the engineering of sigma factors, regulatory units of the bacterial RNA polymerase, could be used to generate better host strains of the model cyanobacterium Synechocystis sp. PCC 6803. Overexpressing the stress-responsive sigB gene under the strong psbA2 promoter (SigB-oe) led to improved tolerance against heat, oxidative stress and toxic end-products. By targeting transcription initiation in the SigB-oe strain, we could simultaneously activate a wide spectrum of cellular protective mechanisms, including carotenoids, the HspA heat shock protein, and highly activated non-photochemical quenching. Yellow fluorescent protein was used to test the capacity of the SigB-oe strain to produce heterologous proteins. In standard conditions, the SigB-oe strain reached a similar production as the control strain, but when cultures were challenged with oxidative stress, the production capacity of SigB-oe surpassed the control strain. We also tested the production of growth-rate-controlled host strains via manipulation of RNA polymerase, but post-transcriptional regulation prevented excessive overexpression of the primary sigma factor SigA, and overproduction of the growth-restricting SigC factor was lethal. Thus, more research is needed before cyanobacteria growth can be manipulated by engineering RNA polymerase.
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Affiliation(s)
- Otso Turunen
- Department of Life Technologies/Molecular Plant Biology, University of Turku, Turku, Finland
| | - Tayyab Saleem
- Department of Life Technologies/Molecular Plant Biology, University of Turku, Turku, Finland
| | - Juha Kurkela
- Department of Life Technologies/Molecular Plant Biology, University of Turku, Turku, Finland
| | - Pauli Kallio
- Department of Life Technologies/Molecular Plant Biology, University of Turku, Turku, Finland
| | - Taina Tyystjärvi
- Department of Life Technologies/Molecular Plant Biology, University of Turku, Turku, Finland
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Kukil K, Lindberg P. Metabolic engineering of Synechocystis sp. PCC 6803 for the improved production of phenylpropanoids. Microb Cell Fact 2024; 23:57. [PMID: 38369470 PMCID: PMC10875765 DOI: 10.1186/s12934-024-02330-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/15/2023] [Accepted: 02/09/2024] [Indexed: 02/20/2024] Open
Abstract
BACKGROUND Phenylpropanoids are a large group of plant secondary metabolites with various biological functions, derived from aromatic amino acids. Cyanobacteria are promising host organisms for sustainable production of plant phenylpropanoids. We have previously engineered Synechocystis sp. PCC 6803 to produce trans-cinnamic acid (tCA) and p-coumaric acid (pCou), the first intermediates of phenylpropanoid pathway, by overexpression of phenylalanine- and tyrosine ammonia lyases. In this study, we aimed to enhance the production of the target compounds tCA and pCou in Synechocystis. RESULTS We eliminated the 4-hydroxyphenylpyruvate dioxygenase (HPPD) activity, which is a competing pathway consuming tyrosine and, possibly, phenylalanine for tocopherol synthesis. Moreover, several genes of the terminal steps of the shikimate pathway were overexpressed alone or in operons, such as aromatic transaminases, feedback insensitive cyclohexadienyl dehydrogenase (TyrC) from Zymomonas mobilis and the chorismate mutase (CM) domain of the fused chorismate mutase/prephenate dehydratase enzyme from Escherichia coli. The obtained engineered strains demonstrated nearly 1.5 times enhanced tCA and pCou production when HPPD was knocked out compared to the parental production strains, accumulating 138 ± 3.5 mg L-1 of tCA and 72.3 ± 10.3 mg L-1 of pCou after seven days of photoautotrophic growth. However, there was no further improvement when any of the pathway genes were overexpressed. Finally, we used previously obtained AtPRM8 and TsPRM8 Synechocystis strains with deregulated shikimate pathway as a background for the overexpression of synthetic constructs with ppd knockout. CONCLUSIONS HPPD elimination enhances the tCA and pCou productivity to a similar extent. The use of PRM8 based strains as a background for overexpression of synthetic constructs, however, did not promote tCA and pCou titers, which indicates a tight regulation of the terminal steps of phenylalanine and tyrosine synthesis. This work contributes to establishing cyanobacteria as hosts for phenylpropanoid production.
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Affiliation(s)
- Kateryna Kukil
- Microbial Chemistry, Department of Chemistry - Ångström, Uppsala University, Box 523, SE 751 20, Uppsala, Sweden
| | - Pia Lindberg
- Microbial Chemistry, Department of Chemistry - Ångström, Uppsala University, Box 523, SE 751 20, Uppsala, Sweden.
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Utharn S, Jantaro S. The adc1 knockout with proC overexpression in Synechocystis sp. PCC 6803 induces a diversion of acetyl-CoA to produce more polyhydroxybutyrate. BIOTECHNOLOGY FOR BIOFUELS AND BIOPRODUCTS 2024; 17:6. [PMID: 38218963 PMCID: PMC10788017 DOI: 10.1186/s13068-024-02458-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/31/2023] [Accepted: 01/05/2024] [Indexed: 01/15/2024]
Abstract
BACKGROUND Lack of nutrients, in particular nitrogen and phosphorus, has been known in the field to sense glutamate production via 2-oxoglutarate and subsequently accelerate carbon storage, including glycogen and polyhydroxybutyrate (PHB), in cyanobacteria, but a few studies have focused on arginine catabolism. In this study, we first time demonstrated that gene manipulation on proC and adc1, related to proline and polyamine syntheses in arginine catabolism, had a significant impact on enhanced PHB production during late growth phase and nutrient-modified conditions. We constructed Synechocystis sp. PCC 6803 with an overexpressing proC gene, encoding Δ1pyrroline-5-carboxylate reductase in proline production, and adc1 disruption resulted in lower polyamine synthesis. RESULTS Three engineered Synechocystis sp. PCC 6803 strains, including a ProC-overexpressing strain (OXP), adc1 mutant, and an OXP strain lacking the adc1 gene (OXP/Δadc1), certainly increased the PHB accumulation under nitrogen and phosphorus deficiency. The possible advantages of single proC overexpression include improved PHB and glycogen storage in late phase of growth and long-term stress situations. However, on day 7 of treatment, the synergistic impact created by OXP/Δadc1 increased PHB synthesis by approximately 48.9% of dry cell weight, resulting in a shorter response to nutrient stress than the OXP strain. Notably, changes in proline and glutamate contents in engineered strains, in particular OXP and OXP/Δadc1, not only partially balanced the intracellular C/N metabolism but also helped cells acclimate under nitrogen (N) and phosphorus (P) stress with higher chlorophyll a content in comparison with wild-type control. CONCLUSIONS In Synechocystis sp. PCC 6803, overexpression of proC resulted in a striking signal to PHB and glycogen accumulation after prolonged nutrient deprivation. When combined with the adc1 disruption, there was a notable increase in PHB production, particularly in situations where there was a strong C supply and a lack of N and P.
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Affiliation(s)
- Suthira Utharn
- Laboratory of Cyanobacterial Biotechnology, Department of Biochemistry, Faculty of Science, Chulalongkorn University, Bangkok, 10330, Thailand
- Program of Biotechnology, Faculty of Science, Chulalongkorn University, Bangkok, 10330, Thailand
| | - Saowarath Jantaro
- Laboratory of Cyanobacterial Biotechnology, Department of Biochemistry, Faculty of Science, Chulalongkorn University, Bangkok, 10330, Thailand.
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Du Z, Bhat WW, Poliner E, Johnson S, Bertucci C, Farre E, Hamberger B. Engineering Nannochloropsis oceanica for the production of diterpenoid compounds. MLIFE 2023; 2:428-437. [PMID: 38818264 PMCID: PMC10989085 DOI: 10.1002/mlf2.12097] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 04/29/2023] [Revised: 08/24/2023] [Accepted: 10/04/2023] [Indexed: 06/01/2024]
Abstract
Photosynthetic microalgae like Nannochloropsis hold enormous potential as sustainable, light-driven biofactories for the production of high-value natural products such as terpenoids. Nannochloropsis oceanica is distinguished as a particularly robust host with extensive genomic and transgenic resources available. Its capacity to grow in wastewater, brackish, and sea waters, coupled with advances in microalgal metabolic engineering, genome editing, and synthetic biology, provides an excellent opportunity. In the present work, we demonstrate how N. oceanica can be engineered to produce the diterpene casbene-an important intermediate in the biosynthesis of pharmacologically relevant macrocyclic diterpenoids. Casbene accumulated after stably expressing and targeting the casbene synthase from Daphne genkwa (DgTPS1) to the algal chloroplast. The engineered strains yielded production titers of up to 0.12 mg g-1 total dry cell weight (DCW) casbene. Heterologous overexpression and chloroplast targeting of two upstream rate-limiting enzymes in the 2-C-methyl- d-erythritol 4-phosphate pathway, Coleus forskohlii 1-deoxy- d-xylulose-5-phosphate synthase and geranylgeranyl diphosphate synthase genes, further enhanced the yield of casbene to a titer up to 1.80 mg g-1 DCW. The results presented here form a basis for further development and production of complex plant diterpenoids in microalgae.
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Affiliation(s)
- Zhi‐Yan Du
- Department of Molecular Biosciences and BioengineeringUniversity of Hawaii at ManoaHonoluluHawaiiUSA
| | - Wajid W. Bhat
- Department of Biochemistry and Molecular BiologyMichigan State UniversityEast LansingMichiganUSA
| | - Eric Poliner
- Department of Plant BiologyMichigan State UniversityEast LansingMichiganUSA
| | - Sean Johnson
- Department of Biochemistry and Molecular BiologyMichigan State UniversityEast LansingMichiganUSA
- Present address:
New England Biolabs Inc.240 County RoadIpswich01938MAUSA
| | - Conor Bertucci
- Department of Biochemistry and Molecular BiologyMichigan State UniversityEast LansingMichiganUSA
| | - Eva Farre
- Department of Plant BiologyMichigan State UniversityEast LansingMichiganUSA
| | - Bjoern Hamberger
- Department of Biochemistry and Molecular BiologyMichigan State UniversityEast LansingMichiganUSA
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Eungrasamee K, Lindblad P, Jantaro S. Improved lipid production and component of mycosporine-like amino acids by co-overexpression of amt1 and aroB genes in Synechocystis sp. PCC6803. Sci Rep 2023; 13:19439. [PMID: 37945676 PMCID: PMC10636201 DOI: 10.1038/s41598-023-46290-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/09/2023] [Accepted: 10/30/2023] [Indexed: 11/12/2023] Open
Abstract
Implementing homologous overexpression of the amt1 (A) and aroB (B) genes involved in ammonium transporter and the synthesis of mycosporine-like amino acids (MAAs) and aromatic amino acids, respectively, we created three engineered Synechocystis sp. PCC6803 strains, including Ox-A, Ox-B, and Ox-AB, to study the utilization of carbon and nitrogen in cyanobacteria for the production of valuable products. With respect to amt1 overexpression, the Ox-A and Ox-AB strains had a greater growth rate under (NH4)2SO4 supplemented condition. Both the higher level of intracellular accumulation of lipids in Ox-A and Ox-AB as well as the increased secretion of free fatty acids from the Ox-A strain were impacted by the late-log phase of cell growth. It is noteworthy that among all strains, the Ox-B strain undoubtedly spotted a substantial accumulation of glycogen as a consequence of aroB overexpression. Additionally, the ammonium condition drove the potent antioxidant activity in Ox strains with a late-log phase, particularly in the Ox-B and Ox-AB strains. This was probably related to the altered MAA component inside the cells. The higher proportion of P4-fraction was induced by the ammonium condition in both Ox-B and Ox-AB, while the noted increase of the P1 component was found in the Ox-A strain.
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Affiliation(s)
- Kamonchanock Eungrasamee
- Laboratory of Cyanobacterial Biotechnology, Department of Biochemistry, Faculty of Science, Chulalongkorn University, Bangkok, 10330, Thailand
| | - Peter Lindblad
- Microbial Chemistry, Department of Chemistry - Ångström, Uppsala University, Box 523, 75120, Uppsala, Sweden
| | - Saowarath Jantaro
- Laboratory of Cyanobacterial Biotechnology, Department of Biochemistry, Faculty of Science, Chulalongkorn University, Bangkok, 10330, Thailand.
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Xie H, Kjellström J, Lindblad P. Sustainable production of photosynthetic isobutanol and 3-methyl-1-butanol in the cyanobacterium Synechocystis sp. PCC 6803. BIOTECHNOLOGY FOR BIOFUELS AND BIOPRODUCTS 2023; 16:134. [PMID: 37684613 PMCID: PMC10492371 DOI: 10.1186/s13068-023-02385-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/21/2023] [Accepted: 08/24/2023] [Indexed: 09/10/2023]
Abstract
BACKGROUND Cyanobacteria are emerging as green cell factories for sustainable biofuel and chemical production, due to their photosynthetic ability to use solar energy, carbon dioxide and water in a direct process. The model cyanobacterial strain Synechocystis sp. PCC 6803 has been engineered for the isobutanol and 3-methyl-1-butanol production by introducing a synthetic 2-keto acid pathway. However, the achieved productions still remained low. In the present study, diverse metabolic engineering strategies were implemented in Synechocystis sp. PCC 6803 for further enhanced photosynthetic isobutanol and 3-methyl-1-butanol production. RESULTS Long-term cultivation was performed on two selected strains resulting in maximum cumulative isobutanol and 3-methyl-1-butanol titers of 1247 mg L-1 and 389 mg L-1, on day 58 and day 48, respectively. Novel Synechocystis strain integrated with a native 2-keto acid pathway was generated and showed a production of 98 mg isobutanol L-1 in short-term screening experiments. Enhanced isobutanol and 3-methyl-1-butanol production was observed when increasing the kivdS286T copy number from three to four. Isobutanol and 3-methyl-1-butanol production was effectively improved when overexpressing selected genes of the central carbon metabolism. Identified genes are potential metabolic engineering targets to further enhance productivity of pyruvate-derived bioproducts in cyanobacteria. CONCLUSIONS Enhanced isobutanol and 3-methyl-1-butanol production was successfully achieved in Synechocystis sp. PCC 6803 strains through diverse metabolic engineering strategies. The maximum cumulative isobutanol and 3-methyl-1-butanol titers, 1247 mg L-1 and 389 mg L-1, respectively, represent the current highest value reported. The significantly enhanced isobutanol and 3-methyl-1-butanol production in this study further pave the way for an industrial application of photosynthetic cyanobacteria-based biofuel and chemical synthesis from CO2.
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Affiliation(s)
- Hao Xie
- Microbial Chemistry, Department of Chemistry-Ångström Laboratory, Uppsala University, Box 523, 75120 Uppsala, Sweden
| | - Jarl Kjellström
- Microbial Chemistry, Department of Chemistry-Ångström Laboratory, Uppsala University, Box 523, 75120 Uppsala, Sweden
| | - Peter Lindblad
- Microbial Chemistry, Department of Chemistry-Ångström Laboratory, Uppsala University, Box 523, 75120 Uppsala, Sweden
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10
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Germann AT, Nakielski A, Dietsch M, Petzel T, Moser D, Triesch S, Westhoff P, Axmann IM. A systematic overexpression approach reveals native targets to increase squalene production in Synechocystis sp. PCC 6803. FRONTIERS IN PLANT SCIENCE 2023; 14:1024981. [PMID: 37324717 PMCID: PMC10266222 DOI: 10.3389/fpls.2023.1024981] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 08/22/2022] [Accepted: 04/28/2023] [Indexed: 06/17/2023]
Abstract
Cyanobacteria are a promising platform for the production of the triterpene squalene (C30), a precursor for all plant and animal sterols, and a highly attractive intermediate towards triterpenoids, a large group of secondary plant metabolites. Synechocystis sp. PCC 6803 natively produces squalene from CO2 through the MEP pathway. Based on the predictions of a constraint-based metabolic model, we took a systematic overexpression approach to quantify native Synechocystis gene's impact on squalene production in a squalene-hopene cyclase gene knock-out strain (Δshc). Our in silico analysis revealed an increased flux through the Calvin-Benson-Bassham cycle in the Δshc mutant compared to the wildtype, including the pentose phosphate pathway, as well as lower glycolysis, while the tricarboxylic acid cycle predicted to be downregulated. Further, all enzymes of the MEP pathway and terpenoid synthesis, as well as enzymes from the central carbon metabolism, Gap2, Tpi and PyrK, were predicted to positively contribute to squalene production upon their overexpression. Each identified target gene was integrated into the genome of Synechocystis Δshc under the control of the rhamnose-inducible promoter Prha. Squalene production was increased in an inducer concentration dependent manner through the overexpression of most predicted genes, which are genes of the MEP pathway, ispH, ispE, and idi, leading to the greatest improvements. Moreover, we were able to overexpress the native squalene synthase gene (sqs) in Synechocystis Δshc, which reached the highest production titer of 13.72 mg l-1 reported for squalene in Synechocystis sp. PCC 6803 so far, thereby providing a promising and sustainable platform for triterpene production.
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Affiliation(s)
- Anna T. Germann
- Institute for Synthetic Microbiology, Department of Biology, Heinrich Heine University Düsseldorf, Düsseldorf, Germany
| | - Andreas Nakielski
- Institute for Synthetic Microbiology, Department of Biology, Heinrich Heine University Düsseldorf, Düsseldorf, Germany
| | - Maximilian Dietsch
- Institute for Synthetic Microbiology, Department of Biology, Heinrich Heine University Düsseldorf, Düsseldorf, Germany
| | - Tim Petzel
- Institute for Synthetic Microbiology, Department of Biology, Heinrich Heine University Düsseldorf, Düsseldorf, Germany
| | - Daniel Moser
- Institute for Plant Sciences and Cluster of Excellence on Plant Sciences (CEPLAS), University of Cologne, Cologne, Germany
| | - Sebastian Triesch
- Institute of Plant Biochemistry, Cluster of Excellence on Plant Science (CEPLAS), Heinrich Heine University, Düsseldorf, Germany
| | - Philipp Westhoff
- Plant Metabolism and Metabolomics Laboratory, Cluster of Excellence on Plant Sciences (CEPLAS), Heinrich Heine University Düsseldorf, Düsseldorf, Germany
| | - Ilka M. Axmann
- Institute for Synthetic Microbiology, Department of Biology, Heinrich Heine University Düsseldorf, Düsseldorf, Germany
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11
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Natesungnoen M, Pongrakhananon V, Lindblad P, Jantaro S. Overexpressing Carotenoid Biosynthetic Genes in Synechocystis sp. PCC 6803 Improved Intracellular Pigments and Antioxidant Activity, Which Can Decrease the Viability and Proliferation of Lung Cancer Cells In Vitro. Int J Mol Sci 2023; 24:ijms24119370. [PMID: 37298323 DOI: 10.3390/ijms24119370] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/04/2023] [Revised: 05/21/2023] [Accepted: 05/23/2023] [Indexed: 06/12/2023] Open
Abstract
In the antioxidant system in cyanobacteria, non-enzymatic antioxidants, such as carotenoids, are considered good candidates for coping with oxidative stress, particularly light stress, and pharmaceutical therapeutic applications. A significant amount of carotenoid accumulation has been recently improved by genetic engineering. In this study, to achieve higher carotenoid production with higher antioxidant activity, we successfully constructed five Synechocystis sp. PCC 6803 strains overexpressing (OX) native genes related to the carotenoids biosynthetic pathway, including OX_CrtB, OX_CrtP, OX_CrtQ, OX_CrtO, and OX_CrtR. All of the engineered strains maintained a significant quantity of myxoxanthophyll, while increasing zeaxanthin and echinenone accumulation. In addition, higher components of zeaxanthin and echinenone were noted in all OX strains, ranging from 14 to 19% and from 17 to 22%, respectively. It is worth noting that the enhanced echinenone component responded to low light conditions, while the increased β-carotene component contributed to a high light stress response. According to the higher antioxidant activity of all OX strains, the carotenoid extracts presented lower IC50 in lung cancer cell lines H460 and A549, with values less than 157 and 139 µg/mL, respectively, when compared with those of WTc, particularly OX_CrtR and OX_CrtQ. A higher proportion of zeaxanthin and β-carotene in OX_CrtR and OX_CrtQ, respectively, may considerably contribute to the ability to treat lung cancer cells with antiproliferative and cytotoxic effects.
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Affiliation(s)
- Maturin Natesungnoen
- Laboratory of Cyanobacterial Biotechnology, Department of Biochemistry, Faculty of Science, Chulalongkorn University, Bangkok 10330, Thailand
| | - Varisa Pongrakhananon
- Department of Pharmacology and Physiology, Faculty of Pharmaceutical Sciences, Chulalongkorn University, Bangkok 10330, Thailand
| | - Peter Lindblad
- Microbial Chemistry, Department of Chemistry-Ångström, Uppsala University, P.O. Box 523, SE-75120 Uppsala, Sweden
| | - Saowarath Jantaro
- Laboratory of Cyanobacterial Biotechnology, Department of Biochemistry, Faculty of Science, Chulalongkorn University, Bangkok 10330, Thailand
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12
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Tharasirivat V, Jantaro S. Increased Biomass and Polyhydroxybutyrate Production by Synechocystis sp. PCC 6803 Overexpressing RuBisCO Genes. Int J Mol Sci 2023; 24:ijms24076415. [PMID: 37047389 PMCID: PMC10094337 DOI: 10.3390/ijms24076415] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/04/2023] [Revised: 03/20/2023] [Accepted: 03/26/2023] [Indexed: 03/31/2023] Open
Abstract
The overexpression of the RuBisCO (rbc) gene has recently become an achievable strategy for increasing cyanobacterial biomass and overcoming the biocompound production restriction. We successfully constructed two rbc-overexpressing Synechocystis sp. PCC 6803 strains (OX), including a strain overexpressing a large subunit of RuBisCO (OXrbcL) and another strain overexpressing all large, chaperone, and small subunits of RuBisCO (OXrbcLXS), resulting in higher and faster growth than wild type under sodium bicarbonate supplementation. This increased biomass of OX strains significantly contributed to the higher polyhydroxybutyrate (PHB) production induced by nutrient-deprived conditions, in particular nitrogen (N) and phosphorus (P). As a result of higher PHB contents in OX strains occurring at days 7 and 9 of nutrient deprivation, this enhancement was apparently made possible by cells preferentially maintaining their internal lipids while accumulating less glycogen. The OXrbcLXS strain, with the highest level of PHB at about 39 %w/dry cell weight (DCW) during 7 days of BG11-NP treatment, contained a lower glycogen level (31.9 %w/DCW) than wild type control (40 %w/DCW). In contrast, the wild type control strain exposed to N- and NP-stresses tended to retain lipid levels and store more glycogen than PHB. In this model, we, for the first time, implemented a RuBisCO-overexpressing cyanobacterial factory for overproducing PHB, destined for biofuel and biomaterial biotechnology.
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13
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Rodrigues JS, Bourgade B, Galle KR, Lindberg P. Mapping competitive pathways to terpenoid biosynthesis in Synechocystis sp. PCC 6803 using an antisense RNA synthetic tool. Microb Cell Fact 2023; 22:35. [PMID: 36823631 PMCID: PMC9951418 DOI: 10.1186/s12934-023-02040-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/24/2022] [Accepted: 02/10/2023] [Indexed: 02/25/2023] Open
Abstract
BACKGROUND Synechocystis sp. PCC 6803 utilizes pyruvate and glyceraldehyde 3-phosphate via the methylerythritol 4-phosphate (MEP) pathway for the biosynthesis of terpenoids. Considering the deep connection of the MEP pathway to the central carbon metabolism, and the low carbon partitioning towards terpenoid biosynthesis, significant changes in the metabolic network are required to increase cyanobacterial production of terpenoids. RESULTS We used the Hfq-MicC antisense RNA regulatory tool, under control of the nickel-inducible PnrsB promoter, to target 12 different genes involved in terpenoid biosynthesis, central carbon metabolism, amino acid biosynthesis and ATP production, and evaluated the changes in the performance of an isoprene-producing cyanobacterial strain. Six candidate targets showed a positive effect on isoprene production: three genes involved in terpenoid biosynthesis (crtE, chlP and thiG), two involved in amino acid biosynthesis (ilvG and ccmA) and one involved in sugar catabolism (gpi). The same strategy was applied to interfere with different parts of the terpenoid biosynthetic pathway in a bisabolene-producing strain. Increased bisabolene production was observed not only when interfering with chlorophyll a biosynthesis, but also with carotenogenesis. CONCLUSIONS We demonstrated that the Hfq-MicC synthetic tool can be used to evaluate the effects of gene knockdown on heterologous terpenoid production, despite the need for further optimization of the technique. Possible targets for future engineering of Synechocystis aiming at improved terpenoid microbial production were identified.
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Affiliation(s)
- João S. Rodrigues
- grid.8993.b0000 0004 1936 9457Department of Chemistry – Ångström, Uppsala University, Uppsala, Sweden
| | - Barbara Bourgade
- grid.8993.b0000 0004 1936 9457Department of Chemistry – Ångström, Uppsala University, Uppsala, Sweden
| | - Karen R. Galle
- grid.8993.b0000 0004 1936 9457Department of Chemistry – Ångström, Uppsala University, Uppsala, Sweden ,grid.5808.50000 0001 1503 7226Faculty of Sciences, University of Porto, Porto, Portugal
| | - Pia Lindberg
- Department of Chemistry - Ångström, Uppsala University, Uppsala, Sweden.
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Bryson AE, Lanier ER, Lau KH, Hamilton JP, Vaillancourt B, Mathieu D, Yocca AE, Miller GP, Edger PP, Buell CR, Hamberger B. Uncovering a miltiradiene biosynthetic gene cluster in the Lamiaceae reveals a dynamic evolutionary trajectory. Nat Commun 2023; 14:343. [PMID: 36670101 PMCID: PMC9860074 DOI: 10.1038/s41467-023-35845-1] [Citation(s) in RCA: 9] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/08/2022] [Accepted: 01/04/2023] [Indexed: 01/22/2023] Open
Abstract
The spatial organization of genes within plant genomes can drive evolution of specialized metabolic pathways. Terpenoids are important specialized metabolites in plants with diverse adaptive functions that enable environmental interactions. Here, we report the genome assemblies of Prunella vulgaris, Plectranthus barbatus, and Leonotis leonurus. We investigate the origin and subsequent evolution of a diterpenoid biosynthetic gene cluster (BGC) together with other seven species within the Lamiaceae (mint) family. Based on core genes found in the BGCs of all species examined across the Lamiaceae, we predict a simplified version of this cluster evolved in an early Lamiaceae ancestor. The current composition of the extant BGCs highlights the dynamic nature of its evolution. We elucidate the terpene backbones generated by the Callicarpa americana BGC enzymes, including miltiradiene and the terpene (+)-kaurene, and show oxidization activities of BGC cytochrome P450s. Our work reveals the fluid nature of BGC assembly and the importance of genome structure in contributing to the origin of metabolites.
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Affiliation(s)
- Abigail E Bryson
- Department of Biochemistry, Michigan State University, East Lansing, MI, USA
| | - Emily R Lanier
- Department of Biochemistry, Michigan State University, East Lansing, MI, USA
| | - Kin H Lau
- Department of Plant Biology, Michigan State University, East Lansing, MI, USA
- Bioinformatics and Biostatistics Core, Van Andel Institute, Grand Rapids, MI, USA
| | - John P Hamilton
- Department of Plant Biology, Michigan State University, East Lansing, MI, USA
- Center for Applied Genetic Technologies, University of Georgia, Athens, GA, USA
| | - Brieanne Vaillancourt
- Department of Plant Biology, Michigan State University, East Lansing, MI, USA
- Center for Applied Genetic Technologies, University of Georgia, Athens, GA, USA
| | - Davis Mathieu
- Department of Biochemistry, Michigan State University, East Lansing, MI, USA
| | - Alan E Yocca
- Department of Plant Biology, Michigan State University, East Lansing, MI, USA
- Department of Horticulture, Michigan State University, East Lansing, MI, USA
| | - Garret P Miller
- Department of Biochemistry, Michigan State University, East Lansing, MI, USA
| | - Patrick P Edger
- Department of Horticulture, Michigan State University, East Lansing, MI, USA
| | - C Robin Buell
- Department of Plant Biology, Michigan State University, East Lansing, MI, USA
- Plant Resilience Institute, Michigan State University, East Lansing, MI, USA
| | - Björn Hamberger
- Department of Biochemistry, Michigan State University, East Lansing, MI, USA.
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15
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Sakamaki Y, Maeda K, Nimura-Matsune K, Chibazakura T, Watanabe S. Characterization of a cyanobacterial rep protein with broad-host range and its utilization for expression vectors. Front Microbiol 2023; 14:1111979. [PMID: 37032853 PMCID: PMC10079941 DOI: 10.3389/fmicb.2023.1111979] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2022] [Accepted: 02/27/2023] [Indexed: 04/11/2023] Open
Abstract
Owing to their photosynthetic capabilities, cyanobacteria are regarded as ecologically friendly hosts for production of biomaterials. However, compared to other bacteria, tools for genetic engineering, especially expression vector systems, are limited. In this study, we characterized a Rep protein, exhibiting replication activity in multiple cyanobacteria and established an expression vector using this protein. Our comprehensive screening using a genomic library of Synechocystis sp. PCC 6803 revealed that a certain region encoding a Rep-related protein (here named Cyanobacterial Rep protein A2: CyRepA2) exhibits high autonomous replication activity in a heterologous host cyanobacterium, Synechococcus elongatus PCC 7942. A reporter assay using GFP showed that the expression vector pYS carrying CyRepA2 can be maintained in not only S. 6803 and S. 7942, but also Synechococcus sp. PCC 7002 and Anabaena sp. PCC 7120. In S. 7942, GFP expression in the pYS-based system was tightly regulated by IPTG, achieving 10-fold higher levels than in the chromosome-based system. Furthermore, pYS could be used together with the conventional vector pEX, which was constructed from an endogenous plasmid in S. 7942. The combination of pYS with other vectors is useful for genetic engineering, such as modifying metabolic pathways, and is expected to improve the performance of cyanobacteria as bioproduction chassis.
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Affiliation(s)
- Yutaka Sakamaki
- Department of Bioscience, Tokyo University of Agriculture, Tokyo, Japan
| | - Kaisei Maeda
- Department of Bioscience, Tokyo University of Agriculture, Tokyo, Japan
- Laboratory for Chemistry and Life Science, Institute of Innovative Research, Tokyo Institute of Technology, Yokohama, Japan
| | | | - Taku Chibazakura
- Department of Bioscience, Tokyo University of Agriculture, Tokyo, Japan
| | - Satoru Watanabe
- Department of Bioscience, Tokyo University of Agriculture, Tokyo, Japan
- *Correspondence: Satoru Watanabe,
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16
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Kumar N, Kar S, Shukla P. Role of regulatory pathways and multi-omics approaches for carbon capture and mitigation in cyanobacteria. BIORESOURCE TECHNOLOGY 2022; 366:128104. [PMID: 36257524 DOI: 10.1016/j.biortech.2022.128104] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/30/2022] [Revised: 10/05/2022] [Accepted: 10/07/2022] [Indexed: 06/16/2023]
Abstract
Cyanobacteria are known for their metabolic potential and carbon capture and sequestration capabilities. These cyanobacteria are not only an effective source for carbon minimization and resource mobilization into value-added products for biotechnological gains. The present review focuses on the detailed description of carbon capture mechanisms exerted by the various cyanobacterial strains, the role of important regulatory pathways, and their subsequent genes responsible for such mechanisms. Moreover, this review will also describe effectual mechanisms of central carbon metabolism like isoprene synthesis, ethylene production, MEP pathway, and the role of Glyoxylate shunt in the carbon sequestration mechanisms. This review also describes some interesting facets of using carbon assimilation mechanisms for valuable bio-products. The role of regulatory pathways and multi-omics approaches in cyanobacteria will not only be crucial towards improving carbon utilization but also will give new insights into utilizing cyanobacterial bioresource for carbon neutrality.
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Affiliation(s)
- Niwas Kumar
- Society for Research and Initiatives for Sustainable Technologies and Institutions, Navrangapura, Ahmedabad 380009, India
| | - Srabani Kar
- Enzyme Technology and Protein Bioinformatics Laboratory, School of Biotechnology, Institute of Science, Banaras Hindu University, Varanasi 221005, India
| | - Pratyoosh Shukla
- Enzyme Technology and Protein Bioinformatics Laboratory, School of Biotechnology, Institute of Science, Banaras Hindu University, Varanasi 221005, India.
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17
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Malihan‐Yap L, Grimm HC, Kourist R. Recent Advances in Cyanobacterial Biotransformations. CHEM-ING-TECH 2022. [DOI: 10.1002/cite.202200077] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Affiliation(s)
- Lenny Malihan‐Yap
- Graz University of Technology Institute of Molecular Biotechnology NAWI Graz 8010 Graz Austria
| | - Hanna C. Grimm
- Graz University of Technology Institute of Molecular Biotechnology NAWI Graz 8010 Graz Austria
| | - Robert Kourist
- Graz University of Technology Institute of Molecular Biotechnology NAWI Graz 8010 Graz Austria
- ACIB GmbH 8010 Graz Austria
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18
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Chen B, Cui M, Wang Y, Shi P, Wang H, Wang F. Recent advances in cellular optogenetics for photomedicine. Adv Drug Deliv Rev 2022; 188:114457. [PMID: 35843507 DOI: 10.1016/j.addr.2022.114457] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/09/2022] [Revised: 06/13/2022] [Accepted: 07/11/2022] [Indexed: 11/26/2022]
Abstract
Since the successful introduction of exogenous photosensitive proteins, channelrhodopsin, to neurons, optogenetics has enabled substantial understanding of profound brain function by selectively manipulating neural circuits. In an optogenetic system, optical stimulation can be precisely delivered to brain tissue to achieve regulation of cellular electrical activity with unprecedented spatio-temporal resolution in living organisms. In recent years, the development of various optical actuators and novel light-delivery techniques has greatly expanded the scope of optogenetics, enabling the control of other signal pathways in non-neuronal cells for different biomedical applications, such as phototherapy and immunotherapy. This review focuses on the recent advances in optogenetic regulation of cellular activities for photomedicine. We discuss emerging optogenetic tools and light-delivery platforms, along with a survey of optogenetic execution in mammalian and microbial cells.
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Affiliation(s)
- Bing Chen
- Department of Materials Science and Engineering, City University of Hong Kong, 83 Tat Chee Avenue, Kowloon, Hong Kong SAR, China; City University of Hong Kong Shenzhen Research Institute, Shenzhen 518057, China
| | - Meihui Cui
- School of Life Sciences, Tianjin University, Tianjin 300072, China
| | - Yuan Wang
- Department of Biomedical Engineering, City University of Hong Kong, 83 Tat Chee Avenue, Kowloon, Hong Kong SAR, China
| | - Peng Shi
- Department of Biomedical Engineering, City University of Hong Kong, 83 Tat Chee Avenue, Kowloon, Hong Kong SAR, China.
| | - Hanjie Wang
- School of Life Sciences, Tianjin University, Tianjin 300072, China.
| | - Feng Wang
- Department of Materials Science and Engineering, City University of Hong Kong, 83 Tat Chee Avenue, Kowloon, Hong Kong SAR, China; City University of Hong Kong Shenzhen Research Institute, Shenzhen 518057, China.
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19
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Vachiranuvathin P, Tharasirivat V, Hemnusornnanon T, Jantaro S. Native SodB Overexpression of Synechocystis sp. PCC 6803 Improves Cell Growth Under Alcohol Stresses Whereas Its Gpx2 Overexpression Impacts on Growth Recovery from Alcohol Stressors. Appl Biochem Biotechnol 2022; 194:5748-5766. [PMID: 35819692 DOI: 10.1007/s12010-022-04061-w] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 06/24/2022] [Indexed: 11/02/2022]
Abstract
To overcome the limited resistance to alcohol stress, genetically engineered Synechocystis sp. PCC 6803 strains with overexpressions of genes related with the ROS detoxification system (sodB and gpx2, which encode superoxide dismutase and glutathione peroxidase, respectively) were developed. Three engineered strains including a sodB-overexpressing strain (OE + S), a gpx2-overexpressing strain (OE + G), and a sodB/gpx2-overexpressing strain (OE + SG) grew similarly as wild-type control under normal condition. When compared to wild-type control, OE + S and OE + SG strains grew faster for 4 days under 2.0% (v/v) ethanol and 0.3% (v/v) n-butanol conditions, as well as having higher chlorophyll a levels. On the other hand, the prominent growth recovery of OE + G and OE + SG was noted within 4 days in normal BG11 medium after treating cells with high alcohol stresses for 1 h, in particular 15% ethanol and 2.5% n-butanol. Under 4 days of recovery from butanol stress, specific levels of intracellular pigments including chlorophyll a and carotenoids were dramatically increased in all modified strains. The overexpression of antioxidant genes then revealed a significant improvement of alcohol tolerance in Synechocystis sp. PCC 6803.
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Affiliation(s)
- Phuwanet Vachiranuvathin
- Laboratory of Cyanobacterial Biotechnology, Department of Biochemistry, Faculty of Science, Chulalongkorn University, Bangkok, 10330, Thailand
| | - Vetaka Tharasirivat
- Laboratory of Cyanobacterial Biotechnology, Department of Biochemistry, Faculty of Science, Chulalongkorn University, Bangkok, 10330, Thailand
| | - Thitaporn Hemnusornnanon
- Laboratory of Cyanobacterial Biotechnology, Department of Biochemistry, Faculty of Science, Chulalongkorn University, Bangkok, 10330, Thailand
| | - Saowarath Jantaro
- Laboratory of Cyanobacterial Biotechnology, Department of Biochemistry, Faculty of Science, Chulalongkorn University, Bangkok, 10330, Thailand.
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20
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Arnesen JA, Belmonte Del Ama A, Jayachandran S, Dahlin J, Rago D, Andersen AJC, Borodina I. Engineering of Yarrowia lipolytica for the production of plant triterpenoids: Asiatic, madecassic, and arjunolic acids. Metab Eng Commun 2022; 14:e00197. [PMID: 35433265 PMCID: PMC9011116 DOI: 10.1016/j.mec.2022.e00197] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/07/2022] [Revised: 03/23/2022] [Accepted: 03/24/2022] [Indexed: 12/13/2022] Open
Abstract
Several plant triterpenoids have valuable pharmaceutical properties, but their production and usage is limited since extraction from plants can burden natural resources, and result in low yields and purity. Here, we engineered oleaginous yeast Yarrowia lipolytica to produce three valuable plant triterpenoids (asiatic, madecassic, and arjunolic acids) by fermentation. First, we established the recombinant production of precursors, ursolic and oleanolic acids, by expressing plant enzymes in free or fused versions in a Y. lipolytica strain previously optimized for squalene production. Engineered strains produced up to 11.6 mg/g DCW ursolic acid or 10.2 mg/g DCW oleanolic acid. The biosynthetic pathway from ursolic acid was extended by expressing the Centella asiatica cytochrome P450 monoxygenases CaCYP716C11p, CaCYP714E19p, and CaCYP716E41p, resulting in the production of trace amounts of asiatic acid and 0.12 mg/g DCW madecassic acid. Expressing the same C. asiatica cytochromes P450 in oleanolic acid-producing strain resulted in the production of oleanane triterpenoids. Expression of CaCYP716C11p in the oleanolic acid-producing strain yielded 8.9 mg/g DCW maslinic acid. Further expression of a codon-optimized CaCYP714E19p resulted in 4.4 mg/g DCW arjunolic acid. Lastly, arjunolic acid production was increased to 9.1 mg/g DCW by swapping the N-terminal domain of CaCYP714E19p with the N-terminal domain from a Kalopanax septemlobus cytochrome P450. In summary, we have demonstrated the production of asiatic, madecassic, and arjunolic acids in a microbial cell factory. The strains and fermentation processes need to be further improved before the production of these molecules by fermentation can be industrialized.
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Affiliation(s)
- Jonathan Asmund Arnesen
- The Novo Nordisk Foundation Center for Biosustainability, Technical University of Denmark, Kemitorvet 220, 2800, Kgs. Lyngby, Denmark
| | - Arian Belmonte Del Ama
- The Novo Nordisk Foundation Center for Biosustainability, Technical University of Denmark, Kemitorvet 220, 2800, Kgs. Lyngby, Denmark
| | - Sidharth Jayachandran
- The Novo Nordisk Foundation Center for Biosustainability, Technical University of Denmark, Kemitorvet 220, 2800, Kgs. Lyngby, Denmark
| | - Jonathan Dahlin
- The Novo Nordisk Foundation Center for Biosustainability, Technical University of Denmark, Kemitorvet 220, 2800, Kgs. Lyngby, Denmark
| | - Daniela Rago
- The Novo Nordisk Foundation Center for Biosustainability, Technical University of Denmark, Kemitorvet 220, 2800, Kgs. Lyngby, Denmark
| | - Aaron John Christian Andersen
- Department of Biotechnology and Biomedicine, Technical University of Denmark, Søltofts plads 221, 2800, Kgs. Lyngby, Denmark
| | - Irina Borodina
- The Novo Nordisk Foundation Center for Biosustainability, Technical University of Denmark, Kemitorvet 220, 2800, Kgs. Lyngby, Denmark
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21
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Ju H, Zhang C, He S, Nan W, Lu W. Construction and optimization of Saccharomyces cerevisiae for synthesizing forskolin. Appl Microbiol Biotechnol 2022; 106:1933-1944. [PMID: 35235006 DOI: 10.1007/s00253-022-11819-z] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/18/2021] [Revised: 02/03/2022] [Accepted: 02/05/2022] [Indexed: 12/27/2022]
Abstract
Forskolin, one of the primary active metabolites of labdane-type diterpenoids, exhibits significant medicinal value, such as anticancer, antiasthmatic, and antihypertensive activities. In this study, we constructed a Saccharomyces cerevisiae cell factory that efficiently produced forskolin. First, a chassis strain that can accumulate 145.8 mg/L 13R-manoyl oxide (13R-MO), the critical precursor of forskolin, was constructed. Then, forskolin was produced by integrating CfCYP76AH15, CfCYP76AH11, CfCYP76AH16, ATR1, and CfACT1-8 into the 13R-MO chassis with a titer of 76.25 μg/L. We confirmed that cytochrome P450 enzymes (P450s) are the rate-limiting step by detecting intermediate metabolite accumulation. Forskolin production reached 759.42 μg/L by optimizing the adaptations between CfCYP76AHs, t66CfCPR, and t30AaCYB5. Moreover, multiple metabolic engineering strategies, including regulation of the target genes' copy numbers, amplification of the endoplasmic reticulum (ER) area, and cofactor metabolism enhancement, were implemented to enhance the metabolic flow to forskolin from 13R-MO, resulting in a final forskolin yield of 21.47 mg/L in shake flasks and 79.33 mg/L in a 5 L bioreactor. These promising results provide guidance for the synthesis of other natural terpenoids in S. cerevisiae, especially for those containing multiple P450s in their synthetic pathways. KEY POINTS: • The forskolin biosynthesis pathway was optimized from the perspective of system metabolism for the first time in S. cerevisiae. • The adaptation and optimization of CYP76AHs, t66CfCPR, and t30AaCYB5 promote forskolin accumulation, which can provide a reference for diterpenoids containing complex pathways, especially multiple P450s pathways. • The forskolin titer of 79.33 mg/L is the highest production currently reported and was achieved by fed-batch fermentation in a 5 L bioreactor.
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Affiliation(s)
- Haiyan Ju
- School of Chemical Engineering and Technology, Tianjin University, Tianjin, 300350, China
| | - Chuanbo Zhang
- School of Chemical Engineering and Technology, Tianjin University, Tianjin, 300350, China
| | - Shifan He
- School of Chemical Engineering and Technology, Tianjin University, Tianjin, 300350, China
| | - Weihua Nan
- School of Chemical Engineering and Technology, Tianjin University, Tianjin, 300350, China
| | - Wenyu Lu
- School of Chemical Engineering and Technology, Tianjin University, Tianjin, 300350, China.
- Key Laboratory of System Bioengineering (Tianjin University), Ministry of Education, Tianjin, 300350, China.
- SynBio Research Platform, Collaborative Innovation Center of Chemical Science and Engineering (Tianjin), Tianjin, 300350, China.
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22
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Sivaramakrishnan R, Incharoensakdi A. Overexpression of fatty acid synthesis genes in Synechocystis sp. PCC 6803 with disrupted glycogen synthesis increases lipid production with further enhancement under copper induced oxidative stress. CHEMOSPHERE 2022; 291:132755. [PMID: 34736940 DOI: 10.1016/j.chemosphere.2021.132755] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/01/2021] [Revised: 10/25/2021] [Accepted: 10/30/2021] [Indexed: 06/13/2023]
Abstract
In the present study, fatty acid synthesis genes such as alpha and beta subunits of acetyl CoA carboxylase (accA and accD) were overexpressed in the glgC (Glucose-1-phosphate adenylyltransferase) knockout Synechocystis sp. PCC 6803. The biomass and lipid contents were evaluated in both the wild type and the engineered strains after copper treatment. The maximum lipid production of 0.981 g/L with the productivity of 81.75 mg/L/d was obtained from the copper treated ΔglgC + A-OX strain, which showed a 3.3-fold increase compared to the untreated wild type with satisfactory biodiesel properties. After copper treatment the knockout strain improved the unsaturated fatty acids level contributing to the increase of the saturated and mono-unsaturated ratio with improvement of the fuel quality. Copper induced oxidative stress also improved the photosynthetic pigments in engineered strains leading to increased tolerance against oxidative stress in the engineered strains. The copper treatment increased the antioxidant enzyme activities in the engineered strains especially in ΔglgC + A-OX strain. The carbon flux to lipid synthesis was enhanced by the engineered strains particularly with the knockout-overexpression strains. The Synechocystis sp. PCC 6803 engineered with ΔglgC + A-OX showed high potential for fuel production after the copper treatment.
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Affiliation(s)
- Ramachandran Sivaramakrishnan
- Laboratory of Cyanobacterial Biotechnology, Department of Biochemistry, Faculty of Science, Chulalongkorn University, Bangkok, 10330, Thailand.
| | - Aran Incharoensakdi
- Laboratory of Cyanobacterial Biotechnology, Department of Biochemistry, Faculty of Science, Chulalongkorn University, Bangkok, 10330, Thailand; Academy of Science, Royal Society of Thailand, Bangkok, 10300, Thailand.
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Xie H, Lindblad P. Expressing 2-keto acid pathway enzymes significantly increases photosynthetic isobutanol production. Microb Cell Fact 2022; 21:17. [PMID: 35105340 PMCID: PMC8805274 DOI: 10.1186/s12934-022-01738-z] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/18/2021] [Accepted: 01/03/2022] [Indexed: 11/20/2022] Open
Abstract
Background Cyanobacteria, photosynthetic microorganisms, are promising green cell factories for chemical production, including biofuels. Isobutanol, a four-carbon alcohol, is considered as a superior candidate as a biofuel for its high energy density with suitable chemical and physical characteristics. The unicellular cyanobacterium Synechocystis PCC 6803 has been successfully engineered for photosynthetic isobutanol production from CO2 and solar energy in a direct process. Results Heterologous expression of α-ketoisovalerate decarboxylase (KivdS286T) is sufficient for isobutanol synthesis via the 2-keto acid pathway in Synechocystis. With additional expression of acetolactate synthase (AlsS), acetohydroxy-acid isomeroreductase (IlvC), dihydroxy-acid dehydratase (IlvD), and alcohol dehydrogenase (Slr1192OP), the Synechocystis strain HX42, with a functional 2-keto acid pathway, showed enhanced isobutanol production reaching 98 mg L−1 in short-term screening experiments. Through modulating kivdS286T copy numbers as well as the composition of the 5′-region, a final Synechocystis strain HX47 with three copies of kivdS286T showed a significantly improved isobutanol production of 144 mg L−1, an 177% increase compared to the previously reported best producing strain under identical conditions. Conclusions This work demonstrates the feasibility to express heterologous genes with a combination of self-replicating plasmid-based system and genome-based system in Synechocystis cells. Obtained isobutanol-producing Synechocystis strains form the base for further investigation of continuous, long-term-photosynthetic isobutanol production from solar energy and carbon dioxide. Graphic abstract ![]()
Supplementary Information The online version contains supplementary material available at 10.1186/s12934-022-01738-z.
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Affiliation(s)
- Hao Xie
- Microbial Chemistry, Department of Chemistry-Ångström Laboratory, Uppsala University, Box 523, 75120, Uppsala, Sweden
| | - Peter Lindblad
- Microbial Chemistry, Department of Chemistry-Ångström Laboratory, Uppsala University, Box 523, 75120, Uppsala, Sweden.
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Kukil K, Lindberg P. Expression of phenylalanine ammonia lyases in Synechocystis sp. PCC 6803 and subsequent improvements of sustainable production of phenylpropanoids. Microb Cell Fact 2022; 21:8. [PMID: 35012528 PMCID: PMC8750797 DOI: 10.1186/s12934-021-01735-8] [Citation(s) in RCA: 11] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/17/2021] [Accepted: 12/29/2021] [Indexed: 11/18/2022] Open
Abstract
Background Phenylpropanoids represent a diverse class of industrially important secondary metabolites, synthesized in plants from phenylalanine and tyrosine. Cyanobacteria have a great potential for sustainable production of phenylpropanoids directly from CO2, due to their photosynthetic lifestyle with a fast growth compared to plants and the ease of generating genetically engineered strains. This study focuses on photosynthetic production of the starting compounds of the phenylpropanoid pathway, trans-cinnamic acid and p-coumaric acid, in the unicellular cyanobacterium Synechocystis sp. PCC 6803 (Synechocystis). Results A selected set of phenylalanine ammonia lyase (PAL) enzymes from different organisms was overexpressed in Synechocystis, and the productivities of the resulting strains compared. To further improve the titer of target compounds, we evaluated the use of stronger expression cassettes for increasing PAL protein levels, as well as knock-out of the laccase gene slr1573, as this was previously reported to prevent degradation of the target compounds in the cell. Finally, to investigate the effect of growth conditions on the production of trans-cinnamic and p-coumaric acids from Synechocystis, cultivation conditions promoting rapid, high density growth were tested. Comparing the different PALs, the highest specific titer was achieved for the strain AtC, expressing PAL from Arabidopsis thaliana. A subsequent increase of protein level did not improve the productivity. Production of target compounds in strains where the slr1573 laccase had been knocked out was found to be lower compared to strains with wild type background, and the Δslr1573 strains exhibited a strong phenotype of slower growth rate and lower pigment content. Application of a high-density cultivation system for the growth of production strains allowed reaching the highest total titers of trans-cinnamic and p-coumaric acids reported so far, at around 0.8 and 0.4 g L−1, respectively, after 4 days. Conclusions Production of trans-cinnamic acid, unlike that of p-coumaric acid, is not limited by the protein level of heterologously expressed PAL in Synechocystis. High density cultivation led to higher titres of both products, while knocking out slr1573 did not have a positive effect on production. This work contributes to capability of exploiting the primary metabolism of cyanobacteria for sustainable production of plant phenylpropanoids. Supplementary Information The online version contains supplementary material available at 10.1186/s12934-021-01735-8.
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Affiliation(s)
- Kateryna Kukil
- Microbial Chemistry, Department of Chemistry - Ångström, Uppsala University, Box 523, SE 751 20, Uppsala, Sweden
| | - Pia Lindberg
- Microbial Chemistry, Department of Chemistry - Ångström, Uppsala University, Box 523, SE 751 20, Uppsala, Sweden.
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25
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Shinde S, Singapuri S, Jiang Z, Long B, Wilcox D, Klatt C, Jones JA, Yuan JS, Wang X. Thermodynamics contributes to high limonene productivity in cyanobacteria. Metab Eng Commun 2022; 14:e00193. [PMID: 35145855 PMCID: PMC8801761 DOI: 10.1016/j.mec.2022.e00193] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/03/2021] [Revised: 01/18/2022] [Accepted: 01/19/2022] [Indexed: 01/02/2023] Open
Abstract
Terpenoids are a large group of secondary metabolites with broad industrial applications. Engineering cyanobacteria is an attractive route for the sustainable production of commodity terpenoids. Currently, a major obstacle lies in the low productivity attained in engineered cyanobacterial strains. Traditional metabolic engineering to improve pathway kinetics has led to limited success in enhancing terpenoid productivity. In this study, we reveal thermodynamics as the main determinant for high limonene productivity in cyanobacteria. Through overexpressing the primary sigma factor, a higher photosynthetic rate was achieved in an engineered strain of Synechococcus elongatus PCC 7942. Computational modeling and wet lab analyses showed an increased flux toward both native carbon sink glycogen synthesis and the non-native limonene synthesis from photosynthate output. On the other hand, comparative proteomics showed decreased expression of terpene pathway enzymes, revealing their limited role in determining terpene flux. Lastly, growth optimization by enhancing photosynthesis has led to a limonene titer of 19 mg/L in 7 days with a maximum productivity of 4.3 mg/L/day. This study highlights the importance of enhancing photosynthesis and substrate input for the high productivity of secondary metabolic pathways, providing a new strategy for future terpenoid engineering in phototrophs. Pathway enzyme engineering marginally increases cyanobacterial terpene production. Sigma factor overexpression improves photosynthetic efficiency in cyanobacteria. Enhanced photosynthesis results in high limonene production in cyanobacteria. Enhanced photosynthesis provides high thermodynamic driving force for terpenes.
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Affiliation(s)
- Shrameeta Shinde
- Department of Microbiology, Miami University, Oxford, OH, 45056, USA
| | - Sonali Singapuri
- Department of Microbiology, Miami University, Oxford, OH, 45056, USA
| | - Zhenxiong Jiang
- Department of Microbiology, Miami University, Oxford, OH, 45056, USA
| | - Bin Long
- Synthetic and Systems Biology Innovation Hub, Department of Plant Pathology and Microbiology, Texas A&M University, College Station, TX, 77843, USA
| | - Danielle Wilcox
- Department of Microbiology, Miami University, Oxford, OH, 45056, USA
| | - Camille Klatt
- Department of Microbiology, Miami University, Oxford, OH, 45056, USA
| | - J. Andrew Jones
- Department of Chemical, Paper, and Biomedical Engineering, Miami University, Oxford, OH, 45056, USA
| | - Joshua S. Yuan
- Synthetic and Systems Biology Innovation Hub, Department of Plant Pathology and Microbiology, Texas A&M University, College Station, TX, 77843, USA
| | - Xin Wang
- Department of Microbiology, Miami University, Oxford, OH, 45056, USA
- Corresponding author.
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26
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The Molecular Toolset and Techniques Required to Build Cyanobacterial Cell Factories. ADVANCES IN BIOCHEMICAL ENGINEERING/BIOTECHNOLOGY 2022. [DOI: 10.1007/10_2022_210] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
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27
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Dookeran ZA, Nielsen DR. Systematic Engineering of Synechococcus elongatus UTEX 2973 for Photosynthetic Production of l-Lysine, Cadaverine, and Glutarate. ACS Synth Biol 2021; 10:3561-3575. [PMID: 34851612 DOI: 10.1021/acssynbio.1c00492] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Amino acids and related targets are typically produced by well-characterized heterotrophs including Corynebacterium glutamicum and Escherichia coli. Cyanobacteria offer an opportunity to supplant these sugar-intensive processes by instead directly utilizing atmospheric CO2 and sunlight. Synechococcus elongatus UTEX 2973 (hereafter UTEX 2973) is a particularly promising photoautotrophic platform due to its fast growth rate. Here, we first engineered UTEX 2973 to overproduce l-lysine (hereafter lysine), after which both cadaverine and glutarate production were achieved through further pathway engineering. To facilitate metabolic engineering, the relative activities of a subset of previously uncharacterized promoters were investigated, in each case, while also comparing the effects of both chromosomal (from neutral site NS3) and episomal (from pAM4788) expressions. Using these parts, lysine overproduction in UTEX 2973 was engineered by introducing a feedback-resistant copy of aspartate kinase (encoded by lysCfbr) and a lysine exporter (encoded by ybjE), both from E. coli. While chromosomal expression resulted in lysine production up to just 325.3 ± 14.8 mg/L after 120 h, this was then increased to 556.3 ± 62.3 mg/L via plasmid-based expression, also surpassing prior reports of photoautotrophic lysine bioproduction. Lastly, additional products of interest were then targeted by modularly extending the lysine pathway to glutarate and cadaverine, two 5-carbon, bioplastic monomers. By this approach, glutarate has so far been produced at final titers reaching 67.5 ± 2.2 mg/L by 96 h, whereas cadaverine has been produced at up to 55.3 ± 6.7 mg/L. Overcoming pathway and/or transport bottlenecks, meanwhile, will be important to improving upon these initial outputs.
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Affiliation(s)
- Zachary A. Dookeran
- Chemical Engineering, School for Engineering of Matter, Transport, and Energy, Arizona State University, P.O. Box 876106, Tempe, Arizona 85287-6106, United States
| | - David R. Nielsen
- Chemical Engineering, School for Engineering of Matter, Transport, and Energy, Arizona State University, P.O. Box 876106, Tempe, Arizona 85287-6106, United States
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28
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Taylor GM, Hitchcock A, Heap JT. Combinatorial assembly platform enabling engineering of genetically stable metabolic pathways in cyanobacteria. Nucleic Acids Res 2021; 49:e123. [PMID: 34554258 PMCID: PMC8643660 DOI: 10.1093/nar/gkab791] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/23/2021] [Revised: 08/18/2021] [Accepted: 09/02/2021] [Indexed: 11/13/2022] Open
Abstract
Cyanobacteria are simple, efficient, genetically-tractable photosynthetic microorganisms which in principle represent ideal biocatalysts for CO2 capture and conversion. However, in practice, genetic instability and low productivity are key, linked problems in engineered cyanobacteria. We took a massively parallel approach, generating and characterising libraries of synthetic promoters and RBSs for the cyanobacterium Synechocystis sp. PCC 6803, and assembling a sparse combinatorial library of millions of metabolic pathway-encoding construct variants. Genetic instability was observed for some variants, which is expected when variants cause metabolic burden. Surprisingly however, in a single combinatorial round without iterative optimisation, 80% of variants chosen at random and cultured photoautotrophically over many generations accumulated the target terpenoid lycopene from atmospheric CO2, apparently overcoming genetic instability. This large-scale parallel metabolic engineering of cyanobacteria provides a new platform for development of genetically stable cyanobacterial biocatalysts for sustainable light-driven production of valuable products directly from CO2, avoiding fossil carbon or competition with food production.
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Affiliation(s)
- George M Taylor
- Imperial College Centre for Synthetic Biology, Department of Life Sciences, Imperial College London, London SW7 2AZ, UK
| | - Andrew Hitchcock
- Department of Molecular Biology and Biotechnology, University of Sheffield, Firth Court, Western Bank, Sheffield S10 2TN, UK
| | - John T Heap
- Imperial College Centre for Synthetic Biology, Department of Life Sciences, Imperial College London, London SW7 2AZ, UK.,School of Life Sciences, The University of Nottingham, Biodiscovery Institute, University Park, Nottingham NG7 2RD, UK
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29
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Dietsch M, Behle A, Westhoff P, Axmann IM. Metabolic engineering of Synechocystis sp. PCC 6803 for the photoproduction of the sesquiterpene valencene. Metab Eng Commun 2021; 13:e00178. [PMID: 34466381 PMCID: PMC8382996 DOI: 10.1016/j.mec.2021.e00178] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/02/2021] [Revised: 07/05/2021] [Accepted: 07/22/2021] [Indexed: 11/05/2022] Open
Abstract
Cyanobacteria are extremely adaptable, fast-growing, solar-powered cell factories that, like plants, are able to convert carbon dioxide into sugar and oxygen and thereby produce a large number of important compounds. Due to their unique phototrophy-associated physiological properties, i.e. naturally occurring isoprenoid metabolic pathway, they represent a highly promising platform for terpenoid biosynthesis. Here, we implemented a carefully devised engineering strategy to boost the biosynthesis of commercially attractive plant sequiterpenes, in particular valencene. Sesquiterpenes are a diverse group of bioactive metabolites, mainly produced in higher plants, but with often low concentrations and expensive downstream extraction. In this work we successfully demonstrate a multi-component engineering approach towards the photosynthetic production of valencene in the cyanobacterium Synechocystis sp. PCC 6803. First, we improved the flux towards valencene by markerless genomic deletions of shc and sqs. Secondly, we downregulated the formation of carotenoids, which are essential for viability of the cell, using CRISPRi on crtE. Finally, we intended to increase the spatial proximity of the two enzymes, ispA and CnVS, involved in valencene formation by creating an operon construct, as well as a fusion protein. Combining the most successful strategies resulted in a valencene production of 19 mg/g DCW in Synechocystis. In this work, we have devised a useful platform for future engineering steps.
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Affiliation(s)
- Maximilian Dietsch
- Institute for Synthetic Microbiology, Department of Biology, Heinrich Heine University Düsseldorf, Düsseldorf, Germany
| | - Anna Behle
- Institute for Synthetic Microbiology, Department of Biology, Heinrich Heine University Düsseldorf, Düsseldorf, Germany
| | - Philipp Westhoff
- Plant Metabolism and Metabolomics Laboratory, Cluster of Excellence on Plant Sciences (CEPLAS), Heinrich Heine University Düsseldorf, D-40001, Düsseldorf, Germany
| | - Ilka M. Axmann
- Institute for Synthetic Microbiology, Department of Biology, Heinrich Heine University Düsseldorf, Düsseldorf, Germany
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30
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Eungrasamee K, Incharoensakdi A, Lindblad P, Jantaro S. Overexpression of lipA or glpD_RuBisCO in the Synechocystis sp. PCC 6803 Mutant Lacking the Aas Gene Enhances Free Fatty-Acid Secretion and Intracellular Lipid Accumulation. Int J Mol Sci 2021; 22:ijms222111468. [PMID: 34768898 PMCID: PMC8583886 DOI: 10.3390/ijms222111468] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/24/2021] [Revised: 10/16/2021] [Accepted: 10/21/2021] [Indexed: 11/16/2022] Open
Abstract
Although engineered cyanobacteria for the production of lipids and fatty acids (FAs) are intelligently used as sustainable biofuel resources, intracellularly overproduced FAs disturb cellular homeostasis and eventually generate lethal toxicity. In order to improve their production by enhancing FFAs secretion into a medium, we constructed three engineered Synechocystis 6803 strains including KA (a mutant lacking the aas gene), KAOL (KA overexpressing lipA, encoding lipase A in membrane lipid hydrolysis), and KAOGR (KA overexpressing quadruple glpD/rbcLXS, related to the CBB cycle). Certain contents of intracellular lipids and secreted FFAs of all engineered strains were higher than those of the wild type. Remarkably, the KAOL strain attained the highest level of secreted FFAs by about 21.9%w/DCW at day 5 of normal BG11 cultivation, with a higher growth rate and shorter doubling time. TEM images provided crucial evidence on the morphological changes of the KAOL strain, which accumulated abundant droplets on regions of thylakoid membranes throughout the cell when compared with wild type. On the other hand, BG11-N condition significantly induced contents of both intracellular lipids and secreted FFAs of the KAOL strain up to 37.2 and 24.5%w/DCW, respectively, within 5 days. Then, for the first time, we shone a spotlight onto the overexpression of lipA in the aas mutant of Synechocystis as another potential strategy to achieve higher FFAs secretion with sustainable growth.
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Affiliation(s)
- Kamonchanock Eungrasamee
- Laboratory of Cyanobacterial Biotechnology, Department of Biochemistry, Faculty of Science, Chulalongkorn University, Bangkok 10330, Thailand; (K.E.); (A.I.)
| | - Aran Incharoensakdi
- Laboratory of Cyanobacterial Biotechnology, Department of Biochemistry, Faculty of Science, Chulalongkorn University, Bangkok 10330, Thailand; (K.E.); (A.I.)
| | - Peter Lindblad
- Microbial Chemistry, Department of Chemistry–Ångström, Uppsala University, Box 523, SE-75120 Uppsala, Sweden;
| | - Saowarath Jantaro
- Laboratory of Cyanobacterial Biotechnology, Department of Biochemistry, Faculty of Science, Chulalongkorn University, Bangkok 10330, Thailand; (K.E.); (A.I.)
- Correspondence: ; Tel.: +66-(0)2-218-5431; Fax: +66-(0)2-218-5418
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Yadav I, Rautela A, Kumar S. Approaches in the photosynthetic production of sustainable fuels by cyanobacteria using tools of synthetic biology. World J Microbiol Biotechnol 2021; 37:201. [PMID: 34664124 DOI: 10.1007/s11274-021-03157-5] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/19/2021] [Accepted: 09/29/2021] [Indexed: 10/20/2022]
Abstract
Cyanobacteria, photosynthetic prokaryotic microorganisms having a simple genetic composition are the prospective photoautotrophic cell factories for the production of a wide range of biofuel molecules. The simple genetic composition of cyanobacteria allows effortless genetic manipulation which leads to increased research endeavors from the synthetic biology approach. Various unicellular model cyanobacterial strains like Synechocystis sp. PCC 6803 and Synechococcus elongatus PCC 7942 have been successfully engineered for biofuels generation. Improved development of synthetic biology tools, genetic modification methods and advancement in transformation techniques to construct a strain that can contain multiple foreign genes in a single operon have vastly expanded the functions that can be used for engineering photosynthetic cyanobacteria for the generation of various biofuel molecules. In this review, recent advancements and approaches in synthetic biology tools used for cyanobacterial genome editing have been discussed. Apart from this, cyanobacterial productions of various fuel molecules like isoprene, limonene, α-farnesene, squalene, alkanes, butanol, and fatty acids, which can be a substitute for petroleum and fossil fuels in the future, have been elaborated.
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Affiliation(s)
- Indrajeet Yadav
- School of Biochemical Engineering, IIT (BHU) Varanasi, Varanasi, Uttar Pradesh, 221005, India
| | - Akhil Rautela
- School of Biochemical Engineering, IIT (BHU) Varanasi, Varanasi, Uttar Pradesh, 221005, India
| | - Sanjay Kumar
- School of Biochemical Engineering, IIT (BHU) Varanasi, Varanasi, Uttar Pradesh, 221005, India.
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32
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Overexpression of glucose-6-phosphate isomerase in Synechocystis sp. PCC 6803 with disrupted glycogen synthesis pathway improves exopolysaccharides synthesis. ALGAL RES 2021. [DOI: 10.1016/j.algal.2021.102357] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
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33
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Sun Y, Calderini E, Kourist R. A Reconstructed Common Ancestor of the Fatty Acid Photo-decarboxylase Clade Shows Photo-decarboxylation Activity and Increased Thermostability. Chembiochem 2021; 22:1833-1840. [PMID: 33539041 PMCID: PMC8252050 DOI: 10.1002/cbic.202000851] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2020] [Revised: 02/04/2021] [Indexed: 12/22/2022]
Abstract
Light-dependent enzymes are a rare type of biocatalyst with high potential for research and biotechnology. A recently discovered fatty acid photo-decarboxylase from Chlorella variabilis NC64A (CvFAP) converts fatty acids to the corresponding hydrocarbons only when irradiated with blue light (400 to 520 nm). To expand the available catalytic diversity for fatty acid decarboxylation, we reconstructed possible ancestral decarboxylases from a set of 12 extant sequences that were classified under the fatty acid decarboxylases clade within the glucose-methanol choline (GMC) oxidoreductase family. One of the resurrected enzymes (ANC1) showed activity in the decarboxylation of fatty acids, showing that the clade indeed contains several photo-decarboxylases. ANC1 has a 15 °C higher melting temperature (Tm ) than the extant CvFAP. Its production yielded 12-fold more protein than this wild type decarboxylase, which offers practical advantages for the biochemical investigation of this photoenzyme. Homology modelling revealed amino acid substitutions to more hydrophilic residues at the surface and shorter flexible loops compared to the wild type. Using ancestral sequence reconstruction, we have expanded the existing pool of confirmed fatty acid photo-decarboxylases, providing access to a more robust catalyst for further development via directed evolution.
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Affiliation(s)
- Yue Sun
- Institute of Molecular BiotechnologyGraz University of TechnologyPetersgasse 148010GrazAustria
| | - Elia Calderini
- Institute of Molecular BiotechnologyGraz University of TechnologyPetersgasse 148010GrazAustria
| | - Robert Kourist
- Institute of Molecular BiotechnologyGraz University of TechnologyPetersgasse 148010GrazAustria
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Ju H, Zhang C, Lu W. Progress in heterologous biosynthesis of forskolin. J Ind Microbiol Biotechnol 2021; 48:kuab009. [PMID: 33928347 PMCID: PMC9113163 DOI: 10.1093/jimb/kuab009] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/04/2020] [Accepted: 12/07/2020] [Indexed: 11/14/2022]
Abstract
Forskolin, a class of labdane-type diterpenoid, has significant medicinal value in anticancer, antiasthmatic, antihypertensive, and heart-strengthening treatments. The main source of natural forskolin is its extraction from the cork tissue of the root of Coleus forskohlii. However, conventional modes of extraction pose several challenges. In recent years, the construction of microbial cell factories to produce medicinal natural products via synthetic biological methods has effectively solved the current problems and is a research hotspot in this field. This review summarizes the recent progress in the heterologous synthesis of forskolin via synthetic biological technology, analyzes the current challenges, and proposes corresponding strategies.
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Affiliation(s)
- Haiyan Ju
- School of Chemical Engineering and Technology, Tianjin
University, Tianjin 300350, P. R.
China
| | - Chuanbo Zhang
- School of Chemical Engineering and Technology, Tianjin
University, Tianjin 300350, P. R.
China
| | - Wenyu Lu
- School of Chemical Engineering and Technology, Tianjin
University, Tianjin 300350, P. R.
China
- Key Laboratory of System Bioengineering (Tianjin University),
Ministry of Education, Tianjin 300350, P. R. China
- SynBio Research Platform, Collaborative Innovation Center of
Chemical Science and Engineering (Tianjin), Tianjin
300350, P. R. China
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35
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Genetic, Genomics, and Responses to Stresses in Cyanobacteria: Biotechnological Implications. Genes (Basel) 2021; 12:genes12040500. [PMID: 33805386 PMCID: PMC8066212 DOI: 10.3390/genes12040500] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/26/2021] [Revised: 03/25/2021] [Accepted: 03/25/2021] [Indexed: 02/07/2023] Open
Abstract
Cyanobacteria are widely-diverse, environmentally crucial photosynthetic prokaryotes of great interests for basic and applied science. Work to date has focused mostly on the three non-nitrogen fixing unicellular species Synechocystis PCC 6803, Synechococcus PCC 7942, and Synechococcus PCC 7002, which have been selected for their genetic and physiological interests summarized in this review. Extensive "omics" data sets have been generated, and genome-scale models (GSM) have been developed for the rational engineering of these cyanobacteria for biotechnological purposes. We presently discuss what should be done to improve our understanding of the genotype-phenotype relationships of these models and generate robust and predictive models of their metabolism. Furthermore, we also emphasize that because Synechocystis PCC 6803, Synechococcus PCC 7942, and Synechococcus PCC 7002 represent only a limited part of the wide biodiversity of cyanobacteria, other species distantly related to these three models, should be studied. Finally, we highlight the need to strengthen the communication between academic researchers, who know well cyanobacteria and can engineer them for biotechnological purposes, but have a limited access to large photobioreactors, and industrial partners who attempt to use natural or engineered cyanobacteria to produce interesting chemicals at reasonable costs, but may lack knowledge on cyanobacterial physiology and metabolism.
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36
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Ma C, Zhang K, Zhang X, Liu G, Zhu T, Che Q, Li D, Zhang G. Heterologous expression and metabolic engineering tools for improving terpenoids production. Curr Opin Biotechnol 2021; 69:281-289. [PMID: 33770560 DOI: 10.1016/j.copbio.2021.02.008] [Citation(s) in RCA: 14] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2021] [Revised: 02/17/2021] [Accepted: 02/19/2021] [Indexed: 02/06/2023]
Abstract
Terpenoids, also referred to as isoprenoids, are the largest group of natural compounds which have contributed significantly to the pharmaceutical industry. The challenges in producing bioactive terpenoids from their original host or by organic synthesis methods spurred the endeavors of producing terpenoids in heterologous host. Modern advances utilizing synthetic biology and biological engineering tools have provided a variety of pharmaceutical terpenoids in large-scale and with diversified structures. In this review, we will summarize the progress in production of typical terpenoids skeletons using heterologous expression method assisted by metabolic engineering techniques, with the purpose of enlightening further efforts in developing advanced cell factories for producing terpenoid based pharmaceuticals.
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Affiliation(s)
- Chuanteng Ma
- Key Laboratory of Marine Drugs, Chinese Ministry of Education, School of Medicine and Pharmacy, Ocean University of China, Qingdao, People's Republic of China
| | - Kaijin Zhang
- Key Laboratory of Marine Drugs, Chinese Ministry of Education, School of Medicine and Pharmacy, Ocean University of China, Qingdao, People's Republic of China
| | - Xianyan Zhang
- Key Laboratory of Marine Drugs, Chinese Ministry of Education, School of Medicine and Pharmacy, Ocean University of China, Qingdao, People's Republic of China
| | - Guowei Liu
- Key Laboratory of Marine Drugs, Chinese Ministry of Education, School of Medicine and Pharmacy, Ocean University of China, Qingdao, People's Republic of China
| | - Tianjiao Zhu
- Key Laboratory of Marine Drugs, Chinese Ministry of Education, School of Medicine and Pharmacy, Ocean University of China, Qingdao, People's Republic of China
| | - Qian Che
- Key Laboratory of Marine Drugs, Chinese Ministry of Education, School of Medicine and Pharmacy, Ocean University of China, Qingdao, People's Republic of China
| | - Dehai Li
- Key Laboratory of Marine Drugs, Chinese Ministry of Education, School of Medicine and Pharmacy, Ocean University of China, Qingdao, People's Republic of China; Laboratory for Marine Drugs and Bioproducts, Pilot National Laboratory for Marine Science and Technology, Qingdao, People's Republic of China
| | - Guojian Zhang
- Key Laboratory of Marine Drugs, Chinese Ministry of Education, School of Medicine and Pharmacy, Ocean University of China, Qingdao, People's Republic of China; Laboratory for Marine Drugs and Bioproducts, Pilot National Laboratory for Marine Science and Technology, Qingdao, People's Republic of China.
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Kang MJ, Hong SJ, Yoo D, Cho BK, Lee H, Choi HK, Kim DM, Lee CG. Photosynthetic production of biodiesel in Synechocystis sp. PCC6803 transformed with insect or plant fatty acid methyltransferase. Bioprocess Biosyst Eng 2021; 44:1433-1439. [PMID: 33656615 DOI: 10.1007/s00449-021-02520-y] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/09/2020] [Accepted: 01/25/2021] [Indexed: 01/10/2023]
Abstract
Biodiesel contains methyl or ethyl esters of long-chain fatty acids and has recently attracted increasing attention. Microalgae have emerged as a sustainable biodiesel production system owing to their photosynthetic potential. However, the conversion of microalgal biomass to biodiesel requires high energy and is costly. This study aimed to overcome the high cost of the pretreatment process by generating cyanobacteria converting fatty acids to fatty acids methyl ester (FAME) in vivo by introducing the fatty acid methyl ester transferase (FAMT) gene. Two FAMT genes from Drosophila melanogaster and Arabidopsis thaliana were selected and their codons were optimized for insertion in the Synechocystis sp. PCC6803 genome through homologous recombination, respectively. FAMT mRNA and protein expression levels were confirmed through reverse-transcription PCR and western blot analysis, respectively. Furthermore, heterologous expression of the FAMT genes yielded FAME, which was analyzed by gas chromatography. We found that FAMT transformants can be further metabolically optimized and applied for commercial production of biodiesel.
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Affiliation(s)
- Mi-Jin Kang
- Department of Biological Engineering, Inha University, Incheon, 22212, Republic of Korea
| | - Seong-Joo Hong
- Department of Biological Engineering, Inha University, Incheon, 22212, Republic of Korea
| | - Danbi Yoo
- Department of Biological Engineering, Inha University, Incheon, 22212, Republic of Korea
| | - Byung-Kwan Cho
- Department of Biological Sciences, Korea Advanced Institute of Science and Technology, Daejeon, 34051, Republic of Korea
| | - Hookeun Lee
- College of Pharmacy, Gachon University, Incheon, 21936, Republic of Korea
| | - Hyung-Kyoon Choi
- College of Pharmacy, Chung-Ang University, Seoul, 06974, Republic of Korea
| | - Dong-Myung Kim
- Department of Fine Chemical Engineering and Applied Chemistry, Chungnam National University, Daejeon, 34134, Republic of Korea
| | - Choul-Gyun Lee
- Department of Biological Engineering, Inha University, Incheon, 22212, Republic of Korea.
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Durall C, Kukil K, Hawkes JA, Albergati A, Lindblad P, Lindberg P. Production of succinate by engineered strains of Synechocystis PCC 6803 overexpressing phosphoenolpyruvate carboxylase and a glyoxylate shunt. Microb Cell Fact 2021; 20:39. [PMID: 33557832 PMCID: PMC7871529 DOI: 10.1186/s12934-021-01529-y] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2020] [Accepted: 01/25/2021] [Indexed: 01/02/2023] Open
Abstract
BACKGROUND Cyanobacteria are promising hosts for the production of various industrially important compounds such as succinate. This study focuses on introduction of the glyoxylate shunt, which is naturally present in only a few cyanobacteria, into Synechocystis PCC 6803. In order to test its impact on cell metabolism, engineered strains were evaluated for succinate accumulation under conditions of light, darkness and anoxic darkness. Each condition was complemented by treatments with 2-thenoyltrifluoroacetone, an inhibitor of succinate dehydrogenase enzyme, and acetate, both in nitrogen replete and deplete medium. RESULTS We were able to introduce genes encoding the glyoxylate shunt, aceA and aceB, encoding isocitrate lyase and malate synthase respectively, into a strain of Synechocystis PCC 6803 engineered to overexpress phosphoenolpyruvate carboxylase. Our results show that complete expression of the glyoxylate shunt results in higher extracellular succinate accumulation compared to the wild type control strain after incubation of cells in darkness and anoxic darkness in the presence of nitrate. Addition of the inhibitor 2-thenoyltrifluoroacetone increased succinate titers in all the conditions tested when nitrate was available. Addition of acetate in the presence of the inhibitor further increased the succinate accumulation, resulting in high levels when phosphoenolpyruvate carboxylase was overexpressed, compared to control strain. However, the highest succinate titer was obtained after dark incubation of an engineered strain with a partial glyoxylate shunt overexpressing isocitrate lyase in addition to phosphoenolpyruvate carboxylase, with only 2-thenoyltrifluoroacetone supplementation to the medium. CONCLUSIONS Heterologous expression of the glyoxylate shunt with its central link to the tricarboxylic acid cycle (TCA) for acetate assimilation provides insight on the coordination of the carbon metabolism in the cell. Phosphoenolpyruvate carboxylase plays an important role in directing carbon flux towards the TCA cycle.
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Affiliation(s)
- Claudia Durall
- Microbial Chemistry, Department of Chemistry-Ångström, Uppsala University, Box 523, 751 20, Uppsala, Sweden
| | - Kateryna Kukil
- Microbial Chemistry, Department of Chemistry-Ångström, Uppsala University, Box 523, 751 20, Uppsala, Sweden
| | - Jeffrey A Hawkes
- Analytical Chemistry, Department of Chemistry-BMC, Uppsala University, Box 599, 751 20, Uppsala, Sweden
| | - Alessia Albergati
- Microbial Chemistry, Department of Chemistry-Ångström, Uppsala University, Box 523, 751 20, Uppsala, Sweden
| | - Peter Lindblad
- Microbial Chemistry, Department of Chemistry-Ångström, Uppsala University, Box 523, 751 20, Uppsala, Sweden
| | - Pia Lindberg
- Microbial Chemistry, Department of Chemistry-Ångström, Uppsala University, Box 523, 751 20, Uppsala, Sweden.
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Lin PC, Zhang F, Pakrasi HB. Enhanced limonene production in a fast-growing cyanobacterium through combinatorial metabolic engineering. Metab Eng Commun 2021; 12:e00164. [PMID: 33659180 PMCID: PMC7890178 DOI: 10.1016/j.mec.2021.e00164] [Citation(s) in RCA: 33] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/11/2020] [Revised: 01/12/2021] [Accepted: 01/19/2021] [Indexed: 12/14/2022] Open
Abstract
Terpenoids are a large and diverse group of natural products with commercial applications. Microbial production of terpenes is considered as a feasible approach for the stable supply of these complex hydrocarbons. Cyanobacteria, photosynthetic prokaryotes, are attractive hosts for sustainable bioproduction, because these autotrophs require only light and CO2 for growth. Despite cyanobacteria having been engineered to produce a variety of compounds, their productivities of terpenes are generally low. Further research is needed to determine the bottleneck reactions for enhancing terpene production in cyanobacteria. In this study, we engineered the fast-growing cyanobacterium Synechococcus elongatus UTEX 2973 to produce a commercially-used terpenoid, limonene. We identified a beneficial mutation in the gene encoding geranylgeranyl pyrophosphate synthase crtE, leading to a 2.5-fold increase in limonene production. The engineered strain produced 16.4 mg L−1 of limonene at a rate of 8.2 mg L−1 day−1, which is 8-fold higher than limonene productivities previously reported in other cyanobacterial species. Furthermore, we employed a combinatorial metabolic engineering approach to optimize genes involved in the upstream pathway of limonene biosynthesis. By modulating the expression of genes encoding the enzymes in the MEP pathway and the geranyl pyrophosphate synthase, we showed that optimization of the expression level is critical to enhance limonene production in cyanobacteria. Engineering of the fast growing cyanobacterium Synechococcus elongatus UTEX 2973 for limonene production. Identification of a beneficial mutation with 2.5-fold increase in limonene productivity. Pathway optimization for limonene biosynthesis.
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Affiliation(s)
- Po-Cheng Lin
- Department of Energy, Environmental & Chemical Engineering, Washington University, St. Louis, MO, 63130, USA
| | - Fuzhong Zhang
- Department of Energy, Environmental & Chemical Engineering, Washington University, St. Louis, MO, 63130, USA
| | - Himadri B Pakrasi
- Department of Biology, Washington University, St. Louis, MO, 63130, USA
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Metabolic Engineering and Synthetic Biology of Cyanobacteria for Carbon Capture and Utilization. BIOTECHNOL BIOPROC E 2020. [DOI: 10.1007/s12257-019-0447-1] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
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Raghavan AR, Salim K, Yadav VG. Optogenetic Control of Heterologous Metabolism in E. coli. ACS Synth Biol 2020; 9:2291-2300. [PMID: 32786352 DOI: 10.1021/acssynbio.9b00454] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
Multiobjective optimization of microbial chassis for the production of xenobiotic compounds requires the implementation of metabolic control strategies that permit dynamic distribution of cellular resources between biomass and product formation. We addressed this need in a previous study by engineering the T7 RNA polymerase to be thermally responsive. The modified polymerase is activated only after the temperature of the host cell falls below 18 °C, and Escherichia coli cells that employ the protein to transcribe the heterologous lycopene biosynthetic pathway exhibit impressive improvements in productivity. We have expanded our toolbox of metabolic switches in the current study by engineering a version of the T7 RNA polymerase that drives the transition between biomass and product formation upon stimulation with red light. The engineered polymerase is expressed as two distinct polypeptide chains. Each chain comprises one of two photoactive components from Arabidopsis thaliana, phytochrome B (PhyB) and phytochrome-integrating factor 3 (PIF3), as well as the N- or C-terminus domains of both, the vacuolar ATPase subunit (VMA) intein of Saccharomyces cerevisiae and the polymerase. Red light drives photodimerization of PhyB and PIF3, which then brings together the N- and C-terminus domains of the VMA intein. Trans-splicing of the intein follows suit and produces an active form of the polymerase that subsequently transcribes any sequence that is under the control of a T7 promoter. The photodimerization also involves a third element, the cyanobacterial chromophore phycocyanobilin (PCB), which too is expressed heterologously by E. coli. We deployed this version of the T7 RNA polymerase to control the production of lycopene in E. coli and observed tight control of pathway expression. We tested a variety of expression configurations to identify one that imposes the lowest metabolic burden on the strain, and we subsequently optimized key parameters such as the source, moment, and duration of photostimulation. We also identified targets for future refinement of the circuit. In summary, our work is a significant advance for the field and greatly expands on previous work by other groups that have used optogenetic circuits to control heterologous metabolism in prokaryotic hosts.
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Affiliation(s)
- Adhithi R. Raghavan
- Department of Chemical and Biological Engineering & School of Biomedical Engineering, The University of British Columbia, Vancouver, V6T 1Z3, Canada
| | - Kevin Salim
- Department of Chemical and Biological Engineering & School of Biomedical Engineering, The University of British Columbia, Vancouver, V6T 1Z3, Canada
| | - Vikramaditya G. Yadav
- Department of Chemical and Biological Engineering & School of Biomedical Engineering, The University of British Columbia, Vancouver, V6T 1Z3, Canada
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Liu J, Wu X, Yao M, Xiao W, Zha J. Chassis engineering for microbial production of chemicals: from natural microbes to synthetic organisms. Curr Opin Biotechnol 2020; 66:105-112. [PMID: 32738762 DOI: 10.1016/j.copbio.2020.06.013] [Citation(s) in RCA: 17] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/15/2020] [Revised: 06/21/2020] [Accepted: 06/21/2020] [Indexed: 12/13/2022]
Abstract
Chassis provides a setting for the expression of heterologous pathway genes, which often requires extensive engineering to achieve complete functions. Traditionally, chassis engineering relies on gene deletion/overexpression for the regulation of precursor/cofactor supply and product transportation, which has generated thousands of high-performance strains. With the development of synthetic biology, chassis modifications have expanded to the synthesis of artificial cellular machineries, creating synthetic cells for the biosynthesis of bioproducts. In this review, we will discuss the development of chassis engineering technologies, termed the first-generation and second-generation technologies, and their applications in the creation of chassis for the production of valued-added chemicals, with an emphasis on synthetic chassis and their applications and potential. The development of chassis engineering technologies will advance rational design and construction of customized chassis for the manufacturing of target bioproducts.
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Affiliation(s)
- Jingyi Liu
- School of Food and Biological Engineering, Shaanxi University of Science and Technology, Xi'an, Shaanxi 710021, China
| | - Xia Wu
- School of Food and Biological Engineering, Shaanxi University of Science and Technology, Xi'an, Shaanxi 710021, China
| | - Mingdong Yao
- Frontier Science Center for Synthetic Biology and Key Laboratory of Systems Bioengineering (Ministry of Education), School of Chemical Engineering and Technology, Tianjin University, Tianjin 300072, China; SynBio Research Platform, Collaborative Innovation Center of Chemical Science and Engineering, Tianjin 300072, China; Frontier Technology Research Institute, Tianjin University, Tianjin 301700, China
| | - Wenhai Xiao
- Frontier Science Center for Synthetic Biology and Key Laboratory of Systems Bioengineering (Ministry of Education), School of Chemical Engineering and Technology, Tianjin University, Tianjin 300072, China; SynBio Research Platform, Collaborative Innovation Center of Chemical Science and Engineering, Tianjin 300072, China.
| | - Jian Zha
- School of Food and Biological Engineering, Shaanxi University of Science and Technology, Xi'an, Shaanxi 710021, China.
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Combining Random Mutagenesis and Metabolic Engineering for Enhanced Tryptophan Production in Synechocystis sp. Strain PCC 6803. Appl Environ Microbiol 2020; 86:AEM.02816-19. [PMID: 32144109 DOI: 10.1128/aem.02816-19] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/03/2019] [Accepted: 02/27/2020] [Indexed: 01/08/2023] Open
Abstract
Tryptophan (Trp) is an essential aromatic amino acid that has value as an animal feed supplement, as the amount found in plant-based sources is insufficient. An alternative to production by engineered microbial fermentation is to have tryptophan biosynthesized by a photosynthetic microorganism that could replace or supplement both the plant and industrially used microbes. We selected Synechocystis sp. strain PCC 6803, a model cyanobacterium, as the host and studied metabolic engineering and random mutagenesis approaches. Previous work on engineering heterotrophic microbes for improved Trp titers has targeted allosteric feedback regulation in enzymes 3-deoxy-d-arabinoheptulosonate 7-phosphate synthase (DAHPS) and anthranilate synthase (AS) as major bottlenecks in the shikimate pathway. In this work, the genes encoding feedback-resistant enzymes from Escherichia coli, aroGfbr and trpEfbr , were overexpressed in the host wild-type (WT) strain. Separately, the WT strain was subjected to random mutagenesis and selection using an amino acid analog to isolate tryptophan-overproducing strains. The randomly mutagenized strains were sequenced in order to identify the mutations that resulted in the desirable phenotypes. Interestingly, the tryptophan overproducers had mutations in the gene encoding chorismate mutase (CM), which catalyzes the conversion of chorismate to prephenate. The best tryptophan overproducer from random mutagenesis was selected as a host for metabolic engineering where aroGfbr and trpEfbr were overexpressed. The best strain developed produced 212 ± 23 mg/liter of tryptophan after 10 days of photoautotrophic growth under 3% (vol/vol) CO2 We demonstrated that a combination of random mutagenesis and metabolic engineering was superior to either individual approach.IMPORTANCE Aromatic amino acids such as tryptophan are primarily used as additives in the animal feed industry and are typically produced using genetically engineered heterotrophic organisms such as Escherichia coli This involves a two-step process, where the substrate such as molasses is first obtained from plants followed by fermentation by heterotrophic organisms. We have engineered photoautotrophic cyanobacterial strains by a combination of random mutagenesis and metabolic engineering. These strains grow on CO2 as the sole carbon source and utilize light as the sole energy source to produce tryptophan, thus converting the two-step process into a single step. Our results show that combining random mutagenesis and metabolic engineering was superior to either approach alone. This study also builds a foundation for further engineering of cyanobacteria for industrial tryptophan production.
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Dienst D, Wichmann J, Mantovani O, Rodrigues JS, Lindberg P. High density cultivation for efficient sesquiterpenoid biosynthesis in Synechocystis sp. PCC 6803. Sci Rep 2020; 10:5932. [PMID: 32246065 PMCID: PMC7125158 DOI: 10.1038/s41598-020-62681-w] [Citation(s) in RCA: 31] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/15/2019] [Accepted: 03/05/2020] [Indexed: 12/23/2022] Open
Abstract
Cyanobacteria and microalgae are attractive photoautotrophic host systems for climate-friendly production of fuels and other value-added biochemicals. However, for economic applications further development and implementation of efficient and sustainable cultivation strategies are essential. Here, we present a comparative study on cyanobacterial sesquiterpenoid biosynthesis in Synechocystis sp. PCC 6803 using a commercial lab-scale High Density Cultivation (HDC) platform in the presence of dodecane as in-situ extractant. Operating in a two-step semi-batch mode over a period of eight days, volumetric yields of (E)-α-bisabolene were more than two orders of magnitude higher than previously reported for cyanobacteria, with final titers of 179.4 ± 20.7 mg * L−1. Likewise, yields of the sesquiterpene alcohols (−)-patchoulol and (−)-α-bisabolol were many times higher than under reference conditions, with final titers of 17.3 ± 1.85 mg * L−1 and 96.3 ± 2.2 mg * L−1, respectively. While specific productivity was compromised particularly for (E)-α-bisabolene in the HDC system during phases of high biomass accumulation rates, volumetric productivity enhancements during linear growth at high densities were more pronounced for (E)-α-bisabolene than for the hydroxylated terpenoids. Together, this study provides additional insights into cell density-related process characteristics, introducing HDC as highly efficient strategy for phototrophic terpenoid production in cyanobacteria.
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Affiliation(s)
- Dennis Dienst
- Department of Chemistry - Ångström, Uppsala University, Box 523, Uppsala, 75120, Sweden
| | - Julian Wichmann
- Faculty of Biology - Center for Biotechnology, Bielefeld University, Bielefeld, Germany
| | - Oliver Mantovani
- Department of Chemistry - Ångström, Uppsala University, Box 523, Uppsala, 75120, Sweden
| | - João S Rodrigues
- Department of Chemistry - Ångström, Uppsala University, Box 523, Uppsala, 75120, Sweden
| | - Pia Lindberg
- Department of Chemistry - Ångström, Uppsala University, Box 523, Uppsala, 75120, Sweden.
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Synechocystis sp. PCC 6803 overexpressing genes involved in CBB cycle and free fatty acid cycling enhances the significant levels of intracellular lipids and secreted free fatty acids. Sci Rep 2020; 10:4515. [PMID: 32161307 PMCID: PMC7066134 DOI: 10.1038/s41598-020-61100-4] [Citation(s) in RCA: 16] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2019] [Accepted: 02/19/2020] [Indexed: 12/17/2022] Open
Abstract
The integrative aspect on carbon fixation and lipid production is firstly implemented in cyanobacterium Synechocystis sp. PCC 6803 using metabolic engineering approach. Genes related to Calvin–Benson–Bassham (CBB) cycle including rbcLXS and glpD and free fatty acid recycling including aas encoding acyl-ACP synthetase were practically manipulated in single, double and triple overexpressions via single homologous recombination. The significantly increased growth rate and intracellular pigment contents were evident in glpD-overexpressing (OG) strain among all strains studied under normal growth condition. The triple aas_glpD_rbcLXS-overexpressing (OAGR) strain notably gave the highest contents of both intracellular lipids and extracellular free fatty acids (FFAs) of about 35.9 and 9.6% w/DCW, respectively, when compared to other strains at day 5 of cultivation. However, the highest intracellular lipid titer and production rate were observed in OA strain at day 5 (228.7 mg/L and 45.7 mg/L/day, respectively) and OG strain at day 10 (358.3 mg/L and 35.8 mg/L/day, respectively) due to their higher growth. For fatty acid (FA) compositions, the main saturated fatty acid of palmitic acid (C16:0) was dominantly found in both intracellular lipid and secreted FFAs fractions. Notably, intracellular FA proportion of myristic acid (C14:0) was induced in all engineered strains whereas the increase of stearic acid (C18:0) composition was found in extracellular FFAs fraction. Altogether, these overexpressing strains efficiently produced higher lipid production via homeostasis balance on both its lipid synthesis and FFAs secretion.
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Introduction of a green algal squalene synthase enhances squalene accumulation in a strain of Synechocystis sp. PCC 6803. Metab Eng Commun 2020; 10:e00125. [PMID: 32123662 PMCID: PMC7038009 DOI: 10.1016/j.mec.2020.e00125] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2019] [Revised: 12/28/2019] [Accepted: 02/03/2020] [Indexed: 11/21/2022] Open
Abstract
Squalene is a triterpene which is produced as a precursor for a wide range of terpenoid compounds in many organisms. It has commercial use in food and cosmetics but could also be used as a feedstock for production of chemicals and fuels, if generated sustainably on a large scale. We have engineered a cyanobacterium, Synechocystis sp. PCC 6803, for production of squalene from CO2. In this organism, squalene is produced via the methylerythritol-phosphate (MEP) pathway for terpenoid biosynthesis, and consumed by the enzyme squalene hopene cyclase (Shc) for generation of hopanoids. The gene encoding Shc in Synechocystis was inactivated (Δshc) by insertion of a gene encoding a squalene synthase from the green alga Botryococcus braunii, under control of an inducible promoter. We could demonstrate elevated squalene generation in cells where the algal enzyme was induced. Heterologous overexpression of genes upstream in the MEP pathway further enhanced the production of squalene, to a level three times higher than the Δshc background strain. During growth in flat panel bioreactors, a squalene titer of 5.1 mg/L of culture was reached.
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Durall C, Lindberg P, Yu J, Lindblad P. Increased ethylene production by overexpressing phosphoenolpyruvate carboxylase in the cyanobacterium Synechocystis PCC 6803. BIOTECHNOLOGY FOR BIOFUELS 2020; 13:16. [PMID: 32010220 PMCID: PMC6988332 DOI: 10.1186/s13068-020-1653-y] [Citation(s) in RCA: 17] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/11/2019] [Accepted: 01/09/2020] [Indexed: 05/06/2023]
Abstract
BACKGROUND Cyanobacteria can be metabolically engineered to convert CO2 to fuels and chemicals such as ethylene. A major challenge in such efforts is to optimize carbon fixation and partition towards target molecules. RESULTS The efe gene encoding an ethylene-forming enzyme was introduced into a strain of the cyanobacterium Synechocystis PCC 6803 with increased phosphoenolpyruvate carboxylase (PEPc) levels. The resulting engineered strain (CD-P) showed significantly increased ethylene production (10.5 ± 3.1 µg mL-1 OD-1 day-1) compared to the control strain (6.4 ± 1.4 µg mL-1 OD-1 day-1). Interestingly, extra copies of the native pepc or the heterologous expression of PEPc from the cyanobacterium Synechococcus PCC 7002 (Synechococcus) in the CD-P, increased ethylene production (19.2 ± 1.3 and 18.3 ± 3.3 µg mL-1 OD-1 day-1, respectively) when the cells were treated with the acetyl-CoA carboxylase inhibitor, cycloxydim. A heterologous expression of phosphoenolpyruvate synthase (PPSA) from Synechococcus in the CD-P also increased ethylene production (16.77 ± 4.48 µg mL-1 OD-1 day-1) showing differences in the regulation of the native and the PPSA from Synechococcus in Synechocystis. CONCLUSIONS This work demonstrates that genetic rewiring of cyanobacterial central carbon metabolism can enhance carbon supply to the TCA cycle and thereby further increase ethylene production.
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Affiliation(s)
- Claudia Durall
- Microbial Chemistry, Department of Chemistry-Ångström, Uppsala University, P.O. Box 523, 751 20 Uppsala, Sweden
| | - Pia Lindberg
- Microbial Chemistry, Department of Chemistry-Ångström, Uppsala University, P.O. Box 523, 751 20 Uppsala, Sweden
| | - Jianping Yu
- Biosciences Center, National Renewable Energy Laboratory, Golden, CO USA
| | - Peter Lindblad
- Microbial Chemistry, Department of Chemistry-Ångström, Uppsala University, P.O. Box 523, 751 20 Uppsala, Sweden
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Metabolic engineering of Synechocystis sp. PCC 6803 for the production of aromatic amino acids and derived phenylpropanoids. Metab Eng 2020; 57:129-139. [DOI: 10.1016/j.ymben.2019.11.002] [Citation(s) in RCA: 29] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/01/2019] [Revised: 10/14/2019] [Accepted: 11/08/2019] [Indexed: 11/22/2022]
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Hasunuma T, Takaki A, Matsuda M, Kato Y, Vavricka CJ, Kondo A. Single-Stage Astaxanthin Production Enhances the Nonmevalonate Pathway and Photosynthetic Central Metabolism in Synechococcus sp. PCC 7002. ACS Synth Biol 2019; 8:2701-2709. [PMID: 31653173 DOI: 10.1021/acssynbio.9b00280] [Citation(s) in RCA: 21] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
The natural pigment astaxanthin is widely used in aquaculture, pharmaceutical, nutraceutical, and cosmetic industries due to superior antioxidant properties. The green alga Haematococcus pluvialis is currently used for commercial production of astaxanthin pigment. However, slow growing H. pluvialis requires a complex two-stage stress-induced process with high light intensity leading to increased contamination risks. In contrast, the fast-growing euryhaline cyanobacterium Synechococcus sp. PCC 7002 (Synechococcus 7002) is able to reach high density under stress-free phototrophic conditions, and is therefore a promising metabolic engineering platform for astaxanthin production. In the present study, genes encoding β-carotene hydroxylase and β-carotene ketolase, from the marine bacterium Brevundimonas sp. SD212, are integrated into the endogenous plasmid of Synechococcus 7002, and then expressed to biosynthesize astaxanthin. Although Synechococcus 7002 does not inherently produce astaxanthin, the recombinant ZW strain yields 3 mg/g dry cell weight astaxanthin from CO2 as the sole carbon source, with significantly higher astaxanthin content than previous cyanobacteria reports. Synechococcus 7002 astaxanthin productivity reached 3.35 mg/L/day after just 2 days in a continuous autotrophic process, which is comparable to the best H. pluvialis astaxanthin productivities when factoring in growth times. Metabolomics analysis reveals increases in fractions of hexose-, pentose-, and triose phosphates along with intermediates involved in the nonmevalonate pathway. Dynamic metabolomics analysis of 13C labeled metabolites clearly indicates flux enhancements in the Calvin cycle and glycolysis resulting from the overexpression of astaxanthin biosynthetic genes. This study suggests that cyanobacteria may enhance central metabolism as well as the nonmevalonate pathway in an attempt to replenish depleted pigments such as β-carotene and zeaxanthin.
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Affiliation(s)
- Tomohisa Hasunuma
- Engineering Biology Research Center, Kobe University, 1-1 Rokkodai, Nada, Kobe 657-8501, Japan
- Graduate School of Science, Technology and Innovation, Kobe University, 1-1 Rokkodai, Nada, Kobe 657-8501, Japan
| | - Ayako Takaki
- Engineering Biology Research Center, Kobe University, 1-1 Rokkodai, Nada, Kobe 657-8501, Japan
| | - Mami Matsuda
- Engineering Biology Research Center, Kobe University, 1-1 Rokkodai, Nada, Kobe 657-8501, Japan
- Graduate School of Science, Technology and Innovation, Kobe University, 1-1 Rokkodai, Nada, Kobe 657-8501, Japan
| | - Yuichi Kato
- Engineering Biology Research Center, Kobe University, 1-1 Rokkodai, Nada, Kobe 657-8501, Japan
- Graduate School of Science, Technology and Innovation, Kobe University, 1-1 Rokkodai, Nada, Kobe 657-8501, Japan
| | - Christopher J. Vavricka
- Graduate School of Science, Technology and Innovation, Kobe University, 1-1 Rokkodai, Nada, Kobe 657-8501, Japan
| | - Akihiko Kondo
- Engineering Biology Research Center, Kobe University, 1-1 Rokkodai, Nada, Kobe 657-8501, Japan
- Graduate School of Science, Technology and Innovation, Kobe University, 1-1 Rokkodai, Nada, Kobe 657-8501, Japan
- Biomass Engineering Program, RIKEN, 1-7-22 Suehiro,
Tsurumi, Yokohama, Kanagawa 230-0045, Japan
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Knoot CJ, Khatri Y, Hohlman RM, Sherman DH, Pakrasi HB. Engineered Production of Hapalindole Alkaloids in the Cyanobacterium Synechococcus sp. UTEX 2973. ACS Synth Biol 2019; 8:1941-1951. [PMID: 31284716 DOI: 10.1021/acssynbio.9b00229] [Citation(s) in RCA: 21] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
Cyanobacteria produce numerous valuable bioactive secondary metabolites (natural products) including alkaloids, isoprenoids, nonribosomal peptides, and polyketides. However, the genomic organization of the biosynthetic gene clusters, complex gene expression patterns, and low compound yields synthesized by the native producers currently limits access to the vast majority of these valuable molecules for detailed studies. Molecular cloning and expression of such clusters in heterotrophic hosts is often precarious owing to genetic and biochemical incompatibilities. Production of such biomolecules in photoautotrophic hosts analogous to the native producers is an attractive alternative that has been under-explored. Here, we describe engineering of the fast-growing cyanobacterium Synechococcus elongatus UTEX 2973 to produce key compounds of the hapalindole family of indole-isonitrile alkaloids. Engineering of the 42-kbp "fam" hapalindole pathway from the cyanobacterium Fischerella ambigua UTEX 1903 into S2973 was accomplished by rationally reconstructing six to seven core biosynthetic genes into synthetic operons. The resulting Synechococcus strains afforded controllable production of indole-isonitrile biosynthetic intermediates and hapalindoles H and 12-epi-hapalindole U at a titer of 0.75-3 mg/L. Exchanging genes encoding fam cyclase enzymes in the synthetic operons was employed to control the stereochemistry of the resulting product. Establishing a robust expression system provides a facile route to scalable levels of similar natural and new forms of bioactive hapalindole derivatives and its structural relatives (e.g., fischerindoles, welwitindolinones). Moreover, this versatile expression system represents a promising tool for exploring other functional characteristics of orphan gene products that mediate the remarkable biosynthesis of this important family of natural products.
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Affiliation(s)
- Cory J. Knoot
- Department of Biology, Washington University, St. Louis, Missouri 63130, United States
| | - Yogan Khatri
- Life Sciences Institute, University of Michigan, Ann Arbor, Michigan 48109, United States
| | - Robert M. Hohlman
- Life Sciences Institute, University of Michigan, Ann Arbor, Michigan 48109, United States
| | - David H. Sherman
- Life Sciences Institute, University of Michigan, Ann Arbor, Michigan 48109, United States
| | - Himadri B. Pakrasi
- Department of Biology, Washington University, St. Louis, Missouri 63130, United States
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