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Cheng L, Zhang Z, Zhu D, Luo Q, Lu X. Glucosylglycerol phosphorylase, a potential novel pathway of microbial glucosylglycerol catabolism. Appl Microbiol Biotechnol 2024; 108:214. [PMID: 38363425 PMCID: PMC10873239 DOI: 10.1007/s00253-024-13035-3] [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: 11/08/2023] [Revised: 01/11/2024] [Accepted: 01/26/2024] [Indexed: 02/17/2024]
Abstract
Glucosylglycerol (GG) is a natural compatible solute that can be synthesized by many cyanobacteria and a few heterotrophic bacteria under high salinity conditions. In cyanobacteria, GG is synthesized by GG-phosphate synthase and GG-phosphate phosphatase, and a hydrolase GGHA catalyzes its degradation. In heterotrophic bacteria (such as some Marinobacter species), a fused form of GG-phosphate phosphatase and GG-phosphate synthase is present, but the cyanobacteria-like degradation pathway is not available. Instead, a phosphorylase GGP, of which the coding gene is located adjacent to the gene that encodes the GG-synthesizing enzyme, is supposed to perform the GG degradation function. In the present study, a GGP homolog from the salt-tolerant M. salinexigens ZYF650T was characterized. The recombinant GGP catalyzed GG decomposition via a two-step process of phosphorolysis and hydrolysis in vitro and exhibited high substrate specificity toward GG. The activity of GGP was enhanced by inorganic salts at low concentrations but significantly inhibited by increasing salt concentrations. While the investigation on the physiological role of GGP in M. salinexigens ZYF650T was limited due to the failed induction of GG production, the heterologous expression of ggp in the living cells of the GG-producing cyanobacterium Synechocystis sp. PCC 6803 significantly reduced the salt-induced GG accumulation. Together, these data suggested that GGP may represent a novel pathway of microbial GG catabolism. KEY POINTS: • GGP catalyzes GG degradation by a process of phosphorolysis and hydrolysis • GGP-catalyzed GG degradation is different from GGHA-based GG degradation • GGP represents a potential novel pathway of microbial GG catabolism.
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Affiliation(s)
- Lin Cheng
- College of Chemical Engineering and Materials Sciences, Tianjin University of Science & Technology, Tianjin, 300457, China
- Key Laboratory of Biofuels, Qingdao Institute of Bioenergy and Bioprocess Technology, Chinese Academy of Sciences, Songling Rd 189, Qingdao, 266101, China
| | - Zhichao Zhang
- Key Laboratory of Biofuels, Qingdao Institute of Bioenergy and Bioprocess Technology, Chinese Academy of Sciences, Songling Rd 189, Qingdao, 266101, China
- Shandong Energy Institute, Songling Rd 189, Qingdao, 266101, China
- Qingdao New Energy Shandong Laboratory, Songling Rd 189, Qingdao, 266101, China
| | - Daling Zhu
- College of Chemical Engineering and Materials Sciences, Tianjin University of Science & Technology, Tianjin, 300457, China.
| | - Quan Luo
- Key Laboratory of Biofuels, Qingdao Institute of Bioenergy and Bioprocess Technology, Chinese Academy of Sciences, Songling Rd 189, Qingdao, 266101, China.
- Shandong Energy Institute, Songling Rd 189, Qingdao, 266101, China.
- Qingdao New Energy Shandong Laboratory, Songling Rd 189, Qingdao, 266101, China.
| | - Xuefeng Lu
- Key Laboratory of Biofuels, Qingdao Institute of Bioenergy and Bioprocess Technology, Chinese Academy of Sciences, Songling Rd 189, Qingdao, 266101, China
- Shandong Energy Institute, Songling Rd 189, Qingdao, 266101, China
- Qingdao New Energy Shandong Laboratory, Songling Rd 189, Qingdao, 266101, China
- Marine Biology and Biotechnology Laboratory, Qingdao National Laboratory for Marine Science and Technology, Wenhai Rd 168, Qingdao, 266237, China
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2
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Wang B, Zuniga C, Guarnieri MT, Zengler K, Betenbaugh M, Young JD. Metabolic engineering of Synechococcus elongatus 7942 for enhanced sucrose biosynthesis. Metab Eng 2023; 80:12-24. [PMID: 37678664 DOI: 10.1016/j.ymben.2023.09.002] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/02/2023] [Revised: 07/28/2023] [Accepted: 09/03/2023] [Indexed: 09/09/2023]
Abstract
The capability of cyanobacteria to produce sucrose from CO2 and light has a remarkable societal and biotechnological impact since sucrose can serve as a carbon and energy source for a variety of heterotrophic organisms and can be converted into value-added products. However, most metabolic engineering efforts have focused on understanding local pathway alterations that drive sucrose biosynthesis and secretion in cyanobacteria rather than analyzing the global flux re-routing that occurs following induction of sucrose production by salt stress. Here, we investigated global metabolic flux alterations in a sucrose-secreting (cscB-overexpressing) strain relative to its wild-type Synechococcus elongatus 7942 parental strain. We used targeted metabolomics, 13C metabolic flux analysis (MFA), and genome-scale modeling (GSM) as complementary approaches to elucidate differences in cellular resource allocation by quantifying metabolic profiles of three cyanobacterial cultures - wild-type S. elongatus 7942 without salt stress (WT), wild-type with salt stress (WT/NaCl), and the cscB-overexpressing strain with salt stress (cscB/NaCl) - all under photoautotrophic conditions. We quantified the substantial rewiring of metabolic fluxes in WT/NaCl and cscB/NaCl cultures relative to WT and identified a metabolic bottleneck limiting carbon fixation and sucrose biosynthesis. This bottleneck was subsequently mitigated through heterologous overexpression of glyceraldehyde-3-phosphate dehydrogenase in an engineered sucrose-secreting strain. Our study also demonstrates that combining 13C-MFA and GSM is a useful strategy to both extend the coverage of MFA beyond central metabolism and to improve the accuracy of flux predictions provided by GSM.
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Affiliation(s)
- Bo Wang
- Department of Chemical and Biomolecular Engineering, Vanderbilt University, Nashville, TN, 37235, USA
| | - Cristal Zuniga
- Department of Pediatrics, University of California, San Diego, CA, 92093, USA; Department of Biology, San Diego State University, San Diego, CA, 92182, USA
| | - Michael T Guarnieri
- Biosciences Center, National Renewable Energy Laboratory, Golden, CO, 80401, USA
| | - Karsten Zengler
- Department of Pediatrics, University of California, San Diego, CA, 92093, USA; Department of Bioengineering, University of California, San Diego, CA, 92093, USA; Center for Microbiome Innovation, University of California, San Diego, CA, 92093, USA
| | - Michael Betenbaugh
- Department of Chemical and Biomolecular Engineering, Johns Hopkins University, Baltimore, MD, 21218, USA
| | - Jamey D Young
- Department of Chemical and Biomolecular Engineering, Vanderbilt University, Nashville, TN, 37235, USA; Department of Molecular Physiology and Biophysics, Vanderbilt University, Nashville, TN, 37235, USA.
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3
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Chen Z, Shen Y, Wang R, Li S, Jia Y. Expression and characterization of a protease-resistant β-d-fructofuranosidase BbFFase9 gene suitable for preparing invert sugars from soybean meal. Heliyon 2023; 9:e19889. [PMID: 37809427 PMCID: PMC10559283 DOI: 10.1016/j.heliyon.2023.e19889] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/09/2023] [Revised: 09/03/2023] [Accepted: 09/05/2023] [Indexed: 10/10/2023] Open
Abstract
A novel gene (BbFFase9), with an ORF of 1557 bp that encodes β-d-fructofuranosidase from Bifidobacteriaceae bacterium, was cloned and expressed in Escherichia coli. The recombinant protein (BbFFase9) was successfully purified and showed a single band with a molecular mass of 66.2 kDa. This was confirmed as a β-d-fructofuranosidase and exhibited a high specific activity of 209.2 U/mg. Although BbFFase9 was a soluble protein, it exhibited excellent tolerance to proteases such as pepsin, trypsin, acidic protease, neutral protease and Flavourzyme®, indicating its potential applicability in different fields. BbFFase9 exhibited typical invertase activity, and highly catalyzed the hydrolysis of the α1↔2β glycosidic linkage in molecules containing fructosyl moieties but with no detectable fructosyltransferase activity. It was optimally active at pH 6.5 and 50 °C and stable between pH 6.0 and 9.0 at a temperature of up to 45 °C for 30 min BbFFase9 could also effectively hydrolyze galacto-oligosaccharides, which are a flatulence factor in soybean meal, thus releasing new types of product such as melibiose and mannotriose, or degrading them into invert sugars, the sweeter fructose and glucose. This study is the first to report the application of this type of β-d-fructofuranosidase.
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Affiliation(s)
- Zhou Chen
- Lab of Enzyme Engineering, School of Food and Health, Beijing Technology and Business University, Beijing, 100048, China
| | - Yimei Shen
- Lab of Enzyme Engineering, School of Food and Health, Beijing Technology and Business University, Beijing, 100048, China
| | - Run Wang
- Lab of Enzyme Engineering, School of Food and Health, Beijing Technology and Business University, Beijing, 100048, China
| | - Siting Li
- Lab of Enzyme Engineering, School of Food and Health, Beijing Technology and Business University, Beijing, 100048, China
| | - Yingmin Jia
- Lab of Enzyme Engineering, School of Food and Health, Beijing Technology and Business University, Beijing, 100048, China
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4
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Zhang S, Sun J, Feng D, Sun H, Cui J, Zeng X, Wu Y, Luan G, Lu X. Unlocking the potentials of cyanobacterial photosynthesis for directly converting carbon dioxide into glucose. Nat Commun 2023; 14:3425. [PMID: 37296173 PMCID: PMC10256809 DOI: 10.1038/s41467-023-39222-w] [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: 02/07/2023] [Accepted: 06/02/2023] [Indexed: 06/12/2023] Open
Abstract
Glucose is the most abundant monosaccharide, serving as an essential energy source for cells in all domains of life and as an important feedstock for the biorefinery industry. The plant-biomass-sugar route dominates the current glucose supply, while the direct conversion of carbon dioxide into glucose through photosynthesis is not well studied. Here, we show that the potential of Synechococcus elongatus PCC 7942 for photosynthetic glucose production can be unlocked by preventing native glucokinase activity. Knocking out two glucokinase genes causes intracellular accumulation of glucose and promotes the formation of a spontaneous mutation in the genome, which eventually leads to glucose secretion. Without heterologous catalysis or transportation genes, glucokinase deficiency and spontaneous genomic mutation lead to a glucose secretion of 1.5 g/L, which is further increased to 5 g/L through metabolic and cultivation engineering. These findings underline the cyanobacterial metabolism plasticities and demonstrate their applications for supporting the direct photosynthetic production of glucose.
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Affiliation(s)
- Shanshan Zhang
- Key Laboratory of Biofuels, Qingdao Institute of Bioenergy and Bioprocess Technology, Chinese Academy of Sciences, No. 189 Songling Road, Qingdao, Shandong, 266101, China
- Shandong Energy Institute, No. 189 Songling Road, Qingdao, Shandong, 266101, China
- Qingdao New Energy Shandong Laboratory, Qingdao, Shandong, 266101, China
- College of Life Science, University of Chinese Academy of Sciences, 100049, Beijing, China
| | - Jiahui Sun
- Key Laboratory of Biofuels, Qingdao Institute of Bioenergy and Bioprocess Technology, Chinese Academy of Sciences, No. 189 Songling Road, Qingdao, Shandong, 266101, China
- Shandong Energy Institute, No. 189 Songling Road, Qingdao, Shandong, 266101, China
- Qingdao New Energy Shandong Laboratory, Qingdao, Shandong, 266101, China
- College of Life Science, University of Chinese Academy of Sciences, 100049, Beijing, China
| | - Dandan Feng
- Key Laboratory of Biofuels, Qingdao Institute of Bioenergy and Bioprocess Technology, Chinese Academy of Sciences, No. 189 Songling Road, Qingdao, Shandong, 266101, China
- Shandong Energy Institute, No. 189 Songling Road, Qingdao, Shandong, 266101, China
- Qingdao New Energy Shandong Laboratory, Qingdao, Shandong, 266101, China
| | - Huili Sun
- Key Laboratory of Biofuels, Qingdao Institute of Bioenergy and Bioprocess Technology, Chinese Academy of Sciences, No. 189 Songling Road, Qingdao, Shandong, 266101, China
- Shandong Energy Institute, No. 189 Songling Road, Qingdao, Shandong, 266101, China
- Qingdao New Energy Shandong Laboratory, Qingdao, Shandong, 266101, China
- College of Life Science, University of Chinese Academy of Sciences, 100049, Beijing, China
| | - Jinyu Cui
- Key Laboratory of Biofuels, Qingdao Institute of Bioenergy and Bioprocess Technology, Chinese Academy of Sciences, No. 189 Songling Road, Qingdao, Shandong, 266101, China
- Shandong Energy Institute, No. 189 Songling Road, Qingdao, Shandong, 266101, China
- Qingdao New Energy Shandong Laboratory, Qingdao, Shandong, 266101, China
| | - Xuexia Zeng
- Key Laboratory of Biofuels, Qingdao Institute of Bioenergy and Bioprocess Technology, Chinese Academy of Sciences, No. 189 Songling Road, Qingdao, Shandong, 266101, China
- Shandong Energy Institute, No. 189 Songling Road, Qingdao, Shandong, 266101, China
- Qingdao New Energy Shandong Laboratory, Qingdao, Shandong, 266101, China
| | - Yannan Wu
- Key Laboratory of Biofuels, Qingdao Institute of Bioenergy and Bioprocess Technology, Chinese Academy of Sciences, No. 189 Songling Road, Qingdao, Shandong, 266101, China
- Shandong Energy Institute, No. 189 Songling Road, Qingdao, Shandong, 266101, China
- Qingdao New Energy Shandong Laboratory, Qingdao, Shandong, 266101, China
| | - Guodong Luan
- Key Laboratory of Biofuels, Qingdao Institute of Bioenergy and Bioprocess Technology, Chinese Academy of Sciences, No. 189 Songling Road, Qingdao, Shandong, 266101, China.
- Shandong Energy Institute, No. 189 Songling Road, Qingdao, Shandong, 266101, China.
- Qingdao New Energy Shandong Laboratory, Qingdao, Shandong, 266101, China.
- College of Life Science, University of Chinese Academy of Sciences, 100049, Beijing, China.
- Dalian National Laboratory for Clean Energy, Dalian, Liaoning, 116023, China.
| | - Xuefeng Lu
- Key Laboratory of Biofuels, Qingdao Institute of Bioenergy and Bioprocess Technology, Chinese Academy of Sciences, No. 189 Songling Road, Qingdao, Shandong, 266101, China.
- Shandong Energy Institute, No. 189 Songling Road, Qingdao, Shandong, 266101, China.
- Qingdao New Energy Shandong Laboratory, Qingdao, Shandong, 266101, China.
- College of Life Science, University of Chinese Academy of Sciences, 100049, Beijing, China.
- Dalian National Laboratory for Clean Energy, Dalian, Liaoning, 116023, China.
- Laboratory for Marine Biology and Biotechnology, Qingdao National Laboratory for Marine Science and Technology, Qingdao, Shandong, 266237, China.
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Nieves-Morión M, Camargo S, Bardi S, Ruiz MT, Flores E, Foster RA. Heterologous expression of genes from a cyanobacterial endosymbiont highlights substrate exchanges with its diatom host. PNAS NEXUS 2023; 2:pgad194. [PMID: 37383020 PMCID: PMC10299089 DOI: 10.1093/pnasnexus/pgad194] [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: 02/09/2023] [Accepted: 06/02/2023] [Indexed: 06/30/2023]
Abstract
A few genera of diatoms are widespread and thrive in low-nutrient waters of the open ocean due to their close association with N2-fixing, filamentous heterocyst-forming cyanobacteria. In one of these symbioses, the symbiont, Richelia euintracellularis, has penetrated the cell envelope of the host, Hemiaulus hauckii, and lives inside the host cytoplasm. How the partners interact, including how the symbiont sustains high rates of N2 fixation, is unstudied. Since R. euintracellularis has evaded isolation, heterologous expression of genes in model laboratory organisms was performed to identify the function of proteins from the endosymbiont. Gene complementation of a cyanobacterial invertase mutant and expression of the protein in Escherichia coli showed that R. euintracellularis HH01 possesses a neutral invertase that splits sucrose producing glucose and fructose. Several solute-binding proteins (SBPs) of ABC transporters encoded in the genome of R. euintracellularis HH01 were expressed in E. coli, and their substrates were characterized. The selected SBPs directly linked the host as the source of several substrates, e.g. sugars (sucrose and galactose), amino acids (glutamate and phenylalanine), and a polyamine (spermidine), to support the cyanobacterial symbiont. Finally, transcripts of genes encoding the invertase and SBPs were consistently detected in wild populations of H. hauckii collected from multiple stations and depths in the western tropical North Atlantic. Our results support the idea that the diatom host provides the endosymbiotic cyanobacterium with organic carbon to fuel N2 fixation. This knowledge is key to understanding the physiology of the globally significant H. hauckii-R. euintracellularis symbiosis.
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Affiliation(s)
- Mercedes Nieves-Morión
- Department of Ecology, Environment and Plant Sciences, Stockholm University, Stockholm SE-106 91, Sweden
- Instituto de Bioquímica Vegetal y Fotosíntesis, CSIC and Universidad de Sevilla, Seville E-41092, Spain
| | - Sergio Camargo
- Instituto de Bioquímica Vegetal y Fotosíntesis, CSIC and Universidad de Sevilla, Seville E-41092, Spain
| | - Sepehr Bardi
- Department of Ecology, Environment and Plant Sciences, Stockholm University, Stockholm SE-106 91, Sweden
| | - María Teresa Ruiz
- Instituto de Bioquímica Vegetal y Fotosíntesis, CSIC and Universidad de Sevilla, Seville E-41092, Spain
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Cantrell M, Cano M, Sebesta J, Paddock T, Xiong W, Chou KJ, Yu J. Manipulation of glycogen and sucrose synthesis increases photosynthetic productivity in cyanobacteria. Front Microbiol 2023; 14:1124274. [PMID: 37275163 PMCID: PMC10233058 DOI: 10.3389/fmicb.2023.1124274] [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: 12/14/2022] [Accepted: 05/05/2023] [Indexed: 06/07/2023] Open
Abstract
Photosynthetic productivity is limited by low energy conversion efficiency in naturally evolved photosynthetic organisms, via multiple mechanisms that are not fully understood. Here we show evidence that extends recent findings that cyanobacteria use "futile" cycles in the synthesis and degradation of carbon compounds to dissipate ATP. Reduction of the glycogen cycle or the sucrose cycle in the model cyanobacterium Synechocystis 6803 led to redirection of cellular energy toward faster growth under simulated outdoor light conditions in photobioreactors that was accompanied by higher energy charge [concentration ratio of ATP/(ATP + ADP)]. Such manipulation of energy metabolism may have potential in engineering microalgal chassis cells to increase productivity of biomass or target metabolites.
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Chen Z, Shen Y, Xu J. A Strategy for Rapid Acquisition of the β-D-Fructofuranosidase Gene through Chemical Synthesis and New Function of Its Encoded Enzyme to Improve Gel Properties during Yogurt Processing. Foods 2023; 12:foods12081704. [PMID: 37107499 PMCID: PMC10137638 DOI: 10.3390/foods12081704] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/06/2023] [Revised: 04/02/2023] [Accepted: 04/10/2023] [Indexed: 04/29/2023] Open
Abstract
A chemical gene synthesis strategy was developed in order to obtain β-D-fructofuranosidase, and a novel gene, AlFFase3, was characterized from Aspergillus luchuensis and expressed in Escherichia coli. The recombinant protein was purified, showing a molecular mass of 68.0 kDa on SDS-PAGE, and displaying a specific activity towards sucrose of up to 771.2 U mg-1, indicating its exceptional enzymatic capacity. AlFFase3 exhibited stability between pH 5.5 and 7.5, with maximal activity at pH 6.5 and 40 °C. Impressively, AlFFase3, as a soluble protein, was resistant to digestion by various common proteases, including Flavourzyme, acidic protease, pepsin, neutral protease, Proteinase K, alkaline proteinase, and trypsin. AlFFase3 also demonstrated significant transfructosylation activity, with a yield of various fructooligosaccharides up to 67%, higher than almost all other reports. Furthermore, we demonstrated that the addition of AlFFase3 enhanced the growth of probiotics in yogurt, thereby increasing its nutritional value. AlFFase3 also improved the formation of yogurt gel, reducing the gel formation time and lowering the elasticity while increasing its viscosity, thereby improving the palatability of yogurt and reducing production costs.
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Affiliation(s)
- Zhou Chen
- Beijing Technology and Business University, Beijing 100048, China
| | - Yimei Shen
- Beijing Technology and Business University, Beijing 100048, China
| | - Jiangqi Xu
- Beijing Technology and Business University, Beijing 100048, China
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Chen Z, Shen Y, Xu J. Efficient Degradation for Raffinose and Stachyose of a β-D-Fructofuranosidase and Its New Function to Improve Gel Properties of Coagulated Fermented-Soymilk. Gels 2023; 9:gels9040345. [PMID: 37102957 PMCID: PMC10137817 DOI: 10.3390/gels9040345] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/16/2023] [Revised: 04/02/2023] [Accepted: 04/13/2023] [Indexed: 04/28/2023] Open
Abstract
A novel β-D-fructofuranosidase gene was identified via database mining from Leptothrix cholodnii. The gene was chemically synthesized and expressed in Escherichia coli, resulting in the production of a highly efficient enzyme known as LcFFase1s. The enzyme exhibited optimal activity at pH 6.5 and a temperature of 50 °C while maintaining stability at pH 5.5-8.0 and a temperature below 50 °C. Furthermore, LcFFase1s exhibited remarkable resistance to commercial proteases and various metal ions that could interfere with its activity. This study also revealed a new hydrolysis function of LcFFase1s, which could completely hydrolyze 2% raffinose and stachyose within 8 h and 24 h, respectively, effectively reducing the flatulence factor in legumes. This discovery expands the potential applications of LcFFase1s. Additionally, the incorporation of LcFFase1s significantly reduced the particle size of coagulated fermented-soymilk gel, resulting in a smoother texture while maintaining the gel hardness and viscosity formed during fermentation. This represents the first report of β-D-fructofuranosidase enhancing coagulated fermented-soymilk gel properties, highlighting promising possibilities for future applications of LcFFase1s. Overall, the exceptional enzymatic properties and unique functions of LcFFase1s render it a valuable tool for numerous applications.
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Affiliation(s)
- Zhou Chen
- School of Food and Health, Beijing Technology and Business University, Beijing 100048, China
| | - Yimei Shen
- School of Food and Health, Beijing Technology and Business University, Beijing 100048, China
| | - Jiangqi Xu
- School of Light Industry, Beijing Technology and Business University, Beijing 100048, China
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Santos-Merino M, Yun L, Ducat DC. Cyanobacteria as cell factories for the photosynthetic production of sucrose. Front Microbiol 2023; 14:1126032. [PMID: 36865782 PMCID: PMC9971976 DOI: 10.3389/fmicb.2023.1126032] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/17/2022] [Accepted: 01/24/2023] [Indexed: 02/16/2023] Open
Abstract
Biofuels and other biologically manufactured sustainable goods are growing in popularity and demand. Carbohydrate feedstocks required for industrial fermentation processes have traditionally been supplied by plant biomass, but the large quantities required to produce replacement commodity products may prevent the long-term feasibility of this approach without alternative strategies to produce sugar feedstocks. Cyanobacteria are under consideration as potential candidates for sustainable production of carbohydrate feedstocks, with potentially lower land and water requirements relative to plants. Several cyanobacterial strains have been genetically engineered to export significant quantities of sugars, especially sucrose. Sucrose is not only naturally synthesized and accumulated by cyanobacteria as a compatible solute to tolerate high salt environments, but also an easily fermentable disaccharide used by many heterotrophic bacteria as a carbon source. In this review, we provide a comprehensive summary of the current knowledge of the endogenous cyanobacterial sucrose synthesis and degradation pathways. We also summarize genetic modifications that have been found to increase sucrose production and secretion. Finally, we consider the current state of synthetic microbial consortia that rely on sugar-secreting cyanobacterial strains, which are co-cultivated alongside heterotrophic microbes able to directly convert the sugars into higher-value compounds (e.g., polyhydroxybutyrates, 3-hydroxypropionic acid, or dyes) in a single-pot reaction. We summarize recent advances reported in such cyanobacteria/heterotroph co-cultivation strategies and provide a perspective on future developments that are likely required to realize their bioindustrial potential.
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Affiliation(s)
- María Santos-Merino
- MSU-DOE Plant Research Laboratory, Michigan State University, East Lansing, MI, United States
| | - Lisa Yun
- MSU-DOE Plant Research Laboratory, Michigan State University, East Lansing, MI, United States
- Department of Biochemistry and Molecular Biology, Michigan State University, East Lansing, MI, United States
| | - Daniel C. Ducat
- MSU-DOE Plant Research Laboratory, Michigan State University, East Lansing, MI, United States
- Department of Biochemistry and Molecular Biology, Michigan State University, East Lansing, MI, United States
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10
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Gao H, Manishimwe C, Yang L, Wang H, Jiang Y, Jiang W, Zhang W, Xin F, Jiang M. Applications of synthetic light-driven microbial consortia for biochemicals production. BIORESOURCE TECHNOLOGY 2022; 351:126954. [PMID: 35288267 DOI: 10.1016/j.biortech.2022.126954] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/03/2022] [Revised: 03/01/2022] [Accepted: 03/03/2022] [Indexed: 06/14/2023]
Abstract
Synthetic microbial consortia provide a versatile and efficient platform for biochemicals production through the labor division. Especially, microbial communities composed of phototrophs and heterotrophs offer a promising alternative, as they can directly convert carbon dioxide (CO2) into chemicals. Within this system, photoautotrophic microbes can convert CO2 into organic carbon for microbial growth and metabolites synthesis by the heterotrophic partners. In return, heterotrophs can provide additional CO2 to support the growth of photoautotrophic microbes. However, the unmatched growing conditions, low stability and production efficiency of synthetic microbial consortia hinder their further applications. Thus, design and construction of mutualistic and stable synthetic light-driven microbial consortia are urgently needed. In this review, the progress of synthetic light-driven microbial consortia for chemicals production was comprehensively summarized. In addition, space-efficient synthetic light-driven microbial consortia in hydrogel system were reviewed. Perspectives on orderly distribution of light-driven microbial consortia associated with 3D printing technology in biomanufacturing were also addressed.
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Affiliation(s)
- Hao Gao
- College of Biotechnology and Pharmaceutical Engineering, State Key Laboratory of Materials-Oriented Chemical Engineering, Nanjing Tech University, Nanjing 211816, PR China
| | - Clarisse Manishimwe
- College of Biotechnology and Pharmaceutical Engineering, State Key Laboratory of Materials-Oriented Chemical Engineering, Nanjing Tech University, Nanjing 211816, PR China
| | - Lu Yang
- College of Biotechnology and Pharmaceutical Engineering, State Key Laboratory of Materials-Oriented Chemical Engineering, Nanjing Tech University, Nanjing 211816, PR China
| | - Hanxiao Wang
- College of Biotechnology and Pharmaceutical Engineering, State Key Laboratory of Materials-Oriented Chemical Engineering, Nanjing Tech University, Nanjing 211816, PR China
| | - Yujia Jiang
- College of Biotechnology and Pharmaceutical Engineering, State Key Laboratory of Materials-Oriented Chemical Engineering, Nanjing Tech University, Nanjing 211816, PR China
| | - Wankui Jiang
- College of Biotechnology and Pharmaceutical Engineering, State Key Laboratory of Materials-Oriented Chemical Engineering, Nanjing Tech University, Nanjing 211816, PR China
| | - Wenming Zhang
- College of Biotechnology and Pharmaceutical Engineering, State Key Laboratory of Materials-Oriented Chemical Engineering, Nanjing Tech University, Nanjing 211816, PR China; Jiangsu National Synergetic Innovation Center for Advanced Materials (SICAM), Nanjing Tech University, Nanjing 211816, PR China
| | - Fengxue Xin
- College of Biotechnology and Pharmaceutical Engineering, State Key Laboratory of Materials-Oriented Chemical Engineering, Nanjing Tech University, Nanjing 211816, PR China; Jiangsu National Synergetic Innovation Center for Advanced Materials (SICAM), Nanjing Tech University, Nanjing 211816, PR China.
| | - Min Jiang
- College of Biotechnology and Pharmaceutical Engineering, State Key Laboratory of Materials-Oriented Chemical Engineering, Nanjing Tech University, Nanjing 211816, PR China; Jiangsu National Synergetic Innovation Center for Advanced Materials (SICAM), Nanjing Tech University, Nanjing 211816, PR China
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11
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Zhuang X, Zhang Y, Xiao AF, Zhang A, Fang B. Applications of Synthetic Biotechnology on Carbon Neutrality Research: A Review on Electrically Driven Microbial and Enzyme Engineering. Front Bioeng Biotechnol 2022; 10:826008. [PMID: 35145960 PMCID: PMC8822124 DOI: 10.3389/fbioe.2022.826008] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2021] [Accepted: 01/04/2022] [Indexed: 12/26/2022] Open
Abstract
With the advancement of science, technology, and productivity, the rapid development of industrial production, transportation, and the exploitation of fossil fuels has gradually led to the accumulation of greenhouse gases and deterioration of global warming. Carbon neutrality is a balance between absorption and emissions achieved by minimizing carbon dioxide (CO2) emissions from human social productive activity through a series of initiatives, including energy substitution and energy efficiency improvement. Then CO2 was offset through forest carbon sequestration and captured at last. Therefore, efficiently reducing CO2 emissions and enhancing CO2 capture are a matter of great urgency. Because many species have the natural CO2 capture properties, more and more scientists focus their attention on developing the biological carbon sequestration technique and further combine with synthetic biotechnology and electricity. In this article, the advances of the synthetic biotechnology method for the most promising organisms were reviewed, such as cyanobacteria, Escherichia coli, and yeast, in which the metabolic pathways were reconstructed to enhance the efficiency of CO2 capture and product synthesis. Furthermore, the electrically driven microbial and enzyme engineering processes are also summarized, in which the critical role and principle of electricity in the process of CO2 capture are canvassed. This review provides detailed summary and analysis of CO2 capture through synthetic biotechnology, which also pave the way for implementing electrically driven combined strategies.
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Affiliation(s)
- Xiaoyan Zhuang
- College of Food and Biology Engineering, Jimei University, Xiamen, China
| | - Yonghui Zhang
- College of Food and Biology Engineering, Jimei University, Xiamen, China
| | - An-Feng Xiao
- College of Food and Biology Engineering, Jimei University, Xiamen, China
| | - Aihui Zhang
- Department of Chemical and Biochemical Engineering, College of Chemistry and Chemical Engineering, Xiamen University, Xiamen, China
- *Correspondence: Aihui Zhang, ; Baishan Fang,
| | - Baishan Fang
- College of Food and Biology Engineering, Jimei University, Xiamen, China
- Department of Chemical and Biochemical Engineering, College of Chemistry and Chemical Engineering, Xiamen University, Xiamen, China
- *Correspondence: Aihui Zhang, ; Baishan Fang,
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12
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Liu J, Cheng J, Huang M, Shen C, Xu K, Xiao Y, Pan W, Fang Z. Identification of an Invertase With High Specific Activity for Raffinose Hydrolysis and Its Application in Soymilk Treatment. Front Microbiol 2021; 12:646801. [PMID: 33897661 PMCID: PMC8060482 DOI: 10.3389/fmicb.2021.646801] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/28/2020] [Accepted: 03/15/2021] [Indexed: 11/23/2022] Open
Abstract
The hydrolyzation of raffinose into melibiose by using invertases under mild conditions improves the nutritional value of soybean products. However, this strategy has received little attention because a suitable invertase remains lacking. In this study, a novel invertase named InvDz13 was screened and purified from Microbacterium trichothecenolyticum and characterized. InvDz13 was one of the invertases with the highest specific activity toward raffinose. Specifically, it had a specific activity of 229 U/mg toward raffinose at pH 6.5 and 35°C. InvDz13 retained more than 80% of its maximum activity at pH 5.5–7.5 and 25–40°C and was resistant to or stimulated by most cations that presented in soymilk. In soymilk treated with InvDz13 under mild conditions, melibiose concentration increased from 3.1 ± 0.2 to 6.1 ± 0.1 mM due to raffinose hydrolyzation by InvDz13. Furthermore, the prebiotic property of InvDz13-treated soymilk was investigated via in vitro fermentation by human gut microbiota. Results showed that InvDz13 treatment increased the proportion of the beneficial bacteria Bifidobacterium and Lactobacillus by 1.6- and 3.7-fold, respectively. By contrast, the populations of Escherichia and Collinsella decreased by 1.8- and 11.7-fold, respectively. Thus, our results proved that the enzymatic hydrolysis of raffinose in soymilk with InvDz13 was practicable and might be an alternative approach to improving the nutritional value of soymilk.
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Affiliation(s)
- Juanjuan Liu
- School of Life Sciences, Anhui University, Hefei, China.,Anhui Key Laboratory of Modern Biomanufacturing, Hefei, China.,Anhui Provincial Engineering Technology Research Center of Microorganisms and Biocatalysis, Hefei, China
| | - Jing Cheng
- School of Life Sciences, Anhui University, Hefei, China.,Anhui Key Laboratory of Modern Biomanufacturing, Hefei, China.,Anhui Provincial Engineering Technology Research Center of Microorganisms and Biocatalysis, Hefei, China
| | - Min Huang
- School of Life Sciences, Anhui University, Hefei, China.,Anhui Key Laboratory of Modern Biomanufacturing, Hefei, China.,Anhui Provincial Engineering Technology Research Center of Microorganisms and Biocatalysis, Hefei, China
| | - Chen Shen
- School of Life Sciences, Anhui University, Hefei, China.,Anhui Key Laboratory of Modern Biomanufacturing, Hefei, China.,Anhui Provincial Engineering Technology Research Center of Microorganisms and Biocatalysis, Hefei, China
| | - Ke Xu
- Anhui RenRenFu Bean Co., Ltd., Hefei, China
| | - Yazhong Xiao
- School of Life Sciences, Anhui University, Hefei, China.,Anhui Key Laboratory of Modern Biomanufacturing, Hefei, China.,Anhui Provincial Engineering Technology Research Center of Microorganisms and Biocatalysis, Hefei, China
| | - Wenjuan Pan
- School of Life Sciences, Anhui University, Hefei, China.,Anhui Key Laboratory of Modern Biomanufacturing, Hefei, China
| | - Zemin Fang
- School of Life Sciences, Anhui University, Hefei, China.,Anhui Key Laboratory of Modern Biomanufacturing, Hefei, China.,Anhui Provincial Engineering Technology Research Center of Microorganisms and Biocatalysis, Hefei, China
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13
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Current knowledge and recent advances in understanding metabolism of the model cyanobacterium Synechocystis sp. PCC 6803. Biosci Rep 2021; 40:222317. [PMID: 32149336 PMCID: PMC7133116 DOI: 10.1042/bsr20193325] [Citation(s) in RCA: 31] [Impact Index Per Article: 10.3] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/27/2020] [Revised: 03/05/2020] [Accepted: 03/06/2020] [Indexed: 02/06/2023] Open
Abstract
Cyanobacteria are key organisms in the global ecosystem, useful models for studying metabolic and physiological processes conserved in photosynthetic organisms, and potential renewable platforms for production of chemicals. Characterizing cyanobacterial metabolism and physiology is key to understanding their role in the environment and unlocking their potential for biotechnology applications. Many aspects of cyanobacterial biology differ from heterotrophic bacteria. For example, most cyanobacteria incorporate a series of internal thylakoid membranes where both oxygenic photosynthesis and respiration occur, while CO2 fixation takes place in specialized compartments termed carboxysomes. In this review, we provide a comprehensive summary of our knowledge on cyanobacterial physiology and the pathways in Synechocystis sp. PCC 6803 (Synechocystis) involved in biosynthesis of sugar-based metabolites, amino acids, nucleotides, lipids, cofactors, vitamins, isoprenoids, pigments and cell wall components, in addition to the proteins involved in metabolite transport. While some pathways are conserved between model cyanobacteria, such as Synechocystis, and model heterotrophic bacteria like Escherichia coli, many enzymes and/or pathways involved in the biosynthesis of key metabolites in cyanobacteria have not been completely characterized. These include pathways required for biosynthesis of chorismate and membrane lipids, nucleotides, several amino acids, vitamins and cofactors, and isoprenoids such as plastoquinone, carotenoids, and tocopherols. Moreover, our understanding of photorespiration, lipopolysaccharide assembly and transport, and degradation of lipids, sucrose, most vitamins and amino acids, and haem, is incomplete. We discuss tools that may aid our understanding of cyanobacterial metabolism, notably CyanoSource, a barcoded library of targeted Synechocystis mutants, which will significantly accelerate characterization of individual proteins.
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14
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Uchiyama J, Ito Y, Matsuhashi A, Ichikawa Y, Sambe M, Kitayama S, Yoshino Y, Moriyama A, Kohga H, Ogawa S, Ohta H. Characterization of Sll1558 in environmental stress tolerance of Synechocystis sp. PCC 6803. PHOTOSYNTHESIS RESEARCH 2020; 146:165-174. [PMID: 32424464 DOI: 10.1007/s11120-020-00759-2] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/28/2019] [Accepted: 05/11/2020] [Indexed: 06/11/2023]
Abstract
So far, the molecular mechanisms underlying the acidic-stress responses of plants are complicated and only fragmentally understood. Here, we investigated the mechanisms responsible for acidic-stress acclimation. Previously, DNA microarray analysis identified the sll1558 gene in Synechocystis sp. PCC 6803 (hereafter called Synechocystis 6803) to be upregulated following short-term acid treatment (1 h at pH 3.0). The sll1558 gene encodes uridine diphosphate-glucose pyrophosphorylase (UDP-glucose pyrophosphorylase), which catalyzes the conversion of glucose-1-phosphate into UDP-glucose. We constructed mutant cells for this gene and analyzed their phenotype. The sll1558 gene did not completely segregate in sll1558 mutant cells; thus, Sll1558 is essential for the survival of Synechocystis 6803. Besides, the partially disrupted sll1558 mutant cells were highly sensitive to acidic stress (pH 6.0) as well as other stress conditions (high salt, high osmolality, high/low temperature, and ultraviolet-B stress); the number of sll1558 transcripts increased under these conditions. UDP-glucose is used for the synthesis of various materials, such as glycolipids. From the membrane lipid composition analysis, digalactosyldiacylglycerol decreased and phosphatidylglycerol increased in the partially disrupted sll1558 mutant cells under acidic stress. These results suggest that sll1558 is important not only for the survival of Synechocystis 6803, but also for tolerance under various stress conditions.
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Affiliation(s)
- Junji Uchiyama
- Department of Biology, Faculty of Science, Tokyo University of Science, Shinjuku-ku, Tokyo, 162-8601, Japan.
- Graduate School of Mathematics and Science Education, Tokyo University of Science, Shinjuku-ku, Tokyo, 162-8601, Japan.
| | - Yutaro Ito
- Department of Biological Science and Technology, Tokyo University of Science, Katsushika-ku, Tokyo, 125-8585, Japan
| | - Ayumi Matsuhashi
- Graduate School of Mathematics and Science Education, Tokyo University of Science, Shinjuku-ku, Tokyo, 162-8601, Japan
| | - Yuta Ichikawa
- Graduate School of Mathematics and Science Education, Tokyo University of Science, Shinjuku-ku, Tokyo, 162-8601, Japan
| | - Mamoru Sambe
- Graduate School of Mathematics and Science Education, Tokyo University of Science, Shinjuku-ku, Tokyo, 162-8601, Japan
| | - Shuichi Kitayama
- Graduate School of Mathematics and Science Education, Tokyo University of Science, Shinjuku-ku, Tokyo, 162-8601, Japan
| | - Yuka Yoshino
- Graduate School of Mathematics and Science Education, Tokyo University of Science, Shinjuku-ku, Tokyo, 162-8601, Japan
| | - Atushi Moriyama
- Graduate School of Mathematics and Science Education, Tokyo University of Science, Shinjuku-ku, Tokyo, 162-8601, Japan
| | - Hidetaka Kohga
- Graduate School of Mathematics and Science Education, Tokyo University of Science, Shinjuku-ku, Tokyo, 162-8601, Japan
| | - Satoru Ogawa
- Laboratory of Electron Microscopy, School of Medicine, Mie University, Tsu, Mie, 514-8507, Japan
| | - Hisataka Ohta
- Department of Biology, Faculty of Science, Tokyo University of Science, Shinjuku-ku, Tokyo, 162-8601, Japan
- Graduate School of Mathematics and Science Education, Tokyo University of Science, Shinjuku-ku, Tokyo, 162-8601, Japan
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15
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Liu D, Liberton M, Hendry JI, Aminian-Dehkordi J, Maranas CD, Pakrasi HB. Engineering biology approaches for food and nutrient production by cyanobacteria. Curr Opin Biotechnol 2020; 67:1-6. [PMID: 33129046 DOI: 10.1016/j.copbio.2020.09.011] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/18/2020] [Revised: 09/13/2020] [Accepted: 09/21/2020] [Indexed: 01/10/2023]
Abstract
As photoautotrophic organisms, cyanobacteria capture and store solar energy in the form of biomass. Cyanobacterial biomass has been an important component of diet and nutrition in several regions for centuries. Synthetic biology strategies are currently being applied to increase the yield and productivity of cyanobacterial biomass by optimizing solar energy utilization and CO2 fixation rates for carbon storage. Likewise, engineering cyanobacteria as cellular factories to synthesize carbohydrates, amino acids, proteins, lipids and fatty acids is providing an attractive way to sustainably produce food and nutrients for human consumption. In this review, we have summarized recent progress in both aspects and prospective trends under development.
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Affiliation(s)
- Deng Liu
- Department of Biology, Washington University, St. Louis, MO 63130, USA
| | - Michelle Liberton
- Department of Biology, Washington University, St. Louis, MO 63130, USA
| | - John I Hendry
- Department of Chemical Engineering, The Pennsylvania State University, University Park, PA 16802, USA
| | - Javad Aminian-Dehkordi
- Department of Chemical Engineering, The Pennsylvania State University, University Park, PA 16802, USA
| | - Costas D Maranas
- Department of Chemical Engineering, The Pennsylvania State University, University Park, PA 16802, USA
| | - Himadri B Pakrasi
- Department of Biology, Washington University, St. Louis, MO 63130, USA.
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16
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Assil-Companioni L, Büchsenschütz HC, Solymosi D, Dyczmons-Nowaczyk NG, Bauer KKF, Wallner S, Macheroux P, Allahverdiyeva Y, Nowaczyk MM, Kourist R. Engineering of NADPH Supply Boosts Photosynthesis-Driven Biotransformations. ACS Catal 2020; 10:11864-11877. [PMID: 33101760 PMCID: PMC7574619 DOI: 10.1021/acscatal.0c02601] [Citation(s) in RCA: 25] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/13/2020] [Revised: 09/04/2020] [Indexed: 02/08/2023]
Abstract
![]()
Light-driven biocatalysis
in recombinant cyanobacteria provides
highly atom-efficient cofactor regeneration via photosynthesis,
thereby remediating constraints associated with sacrificial cosubstrates.
However, despite the remarkable specific activities of photobiocatalysts,
self-shading at moderate-high cell densities limits efficient space-time-yields
of heterologous enzymatic reactions. Moreover, efficient integration
of an artificial electron sink into the tightly regulated network
of cyanobacterial electron pathways can be highly challenging. Here,
we used C=C bond reduction of 2-methylmaleimide by the NADPH-dependent
ene-reductase YqjM as a model reaction for light-dependent biotransformations.
Time-resolved NADPH fluorescence spectroscopy allowed direct monitoring
of in-cell YqjM activity and revealed differences in NADPH steady-state
levels and oxidation kinetics between different genetic constructs.
This effect correlates with specific activities of whole-cells, which
demonstrated conversions of >99%. Further channelling of electrons
toward heterologous YqjM by inactivation of the flavodiiron proteins
(Flv1/Flv3) led to a 2-fold improvement in specific activity at moderate
cell densities, thereby elucidating the possibility of accelerating
light-driven biotransformations by the removal of natural competing
electron sinks. In the best case, an initial product formation rate
of 18.3 mmol h–1 L–1 was reached,
allowing the complete conversion of a 60 mM substrate solution within
4 h.
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Affiliation(s)
- Leen Assil-Companioni
- Institute of Molecular Biotechnology, Graz University of Technology, Petersgasse 14, 8010 Graz, Austria
- ACIB GmbH, Petersgasse 14, 8010 Graz, Austria
| | - Hanna C. Büchsenschütz
- Institute of Molecular Biotechnology, Graz University of Technology, Petersgasse 14, 8010 Graz, Austria
| | - Dániel Solymosi
- Molecular Plant Biology unit, Department of Biochemistry, Faculty of Science and Engineering, University of Turku, Turku 20014, Finland
| | - Nina G. Dyczmons-Nowaczyk
- Department of Plant Biochemistry, Faculty of Biology & Biotechnology, Ruhr University Bochum, 44780 Bochum, Germany
| | - Kristin K. F. Bauer
- Institute of Molecular Biotechnology, Graz University of Technology, Petersgasse 14, 8010 Graz, Austria
| | - Silvia Wallner
- Institute of Biochemistry, Graz University of Technology, Petersgasse 10, 8010 Graz, Austria
| | - Peter Macheroux
- Institute of Biochemistry, Graz University of Technology, Petersgasse 10, 8010 Graz, Austria
| | - Yagut Allahverdiyeva
- Molecular Plant Biology unit, Department of Biochemistry, Faculty of Science and Engineering, University of Turku, Turku 20014, Finland
| | - Marc M. Nowaczyk
- Department of Plant Biochemistry, Faculty of Biology & Biotechnology, Ruhr University Bochum, 44780 Bochum, Germany
| | - Robert Kourist
- Institute of Molecular Biotechnology, Graz University of Technology, Petersgasse 14, 8010 Graz, Austria
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17
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Freshwater Cyanobacterium Synechococcus elongatus PCC 7942 Adapts to an Environment with Salt Stress via Ion-Induced Enzymatic Balance of Compatible Solutes. Appl Environ Microbiol 2020; 86:AEM.02904-19. [PMID: 31953341 DOI: 10.1128/aem.02904-19] [Citation(s) in RCA: 21] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/12/2019] [Accepted: 01/12/2020] [Indexed: 11/20/2022] Open
Abstract
Salinity is one of the most important abiotic factors in various natural habitats of microbes. Cyanobacteria are the most widely distributed family of photosynthetic microorganisms in environments with fluctuating salinity. In response to salt stress, many cyanobacteria de novo synthesize compatible solutes to maintain osmotic balance in the cell. However, the regulation of intracellular accumulation of these compounds is still not well understood. The freshwater cyanobacterium Synechococcus elongatus PCC 7942 (Syn7942) exclusively accumulates sucrose as a compatible solute upon salt stress and is thus an ideal model microorganism for studying the metabolism of compatible solute dynamics. Here, we focused on elucidating the regulatory mechanisms involved in salt-induced sucrose accumulation in Syn7942. Using a series of physiological and biochemical experiments, we showed that the ionic effect of salt stress plays an important role in inducing sucrose synthesis, whereby elevated ion concentration directly activates the sucrose-synthesizing enzyme sucrose-phosphate synthase and simultaneously inhibits the sucrose-degrading enzyme invertase, resulting in a rapid sucrose accumulation. Thus, we propose a novel mechanism for cyanobacterial adaption to salt stress and fluctuating salinity, i.e., the ion-induced synergistic modulation of the enzymes synthesizing and degrading compatible solutes. These findings greatly enhance our current understanding of microbial adaptation to salt.IMPORTANCE Most microbes de novo synthesize compatible solutes for adaptation to salt stress or fluctuating salinity environments. However, to date, one of the core questions involved in these physiological processes, i.e., the regulation of salt-induced compatible solute biosynthesis, is still not well understood. Here, this issue was systematically investigated by employing the model freshwater cyanobacterium Synechococcus elongatus PCC 7942. A novel mechanism for cyanobacterial adaption to salt stress and fluctuating salinity, i.e., the ion-induced synergistic modulation of key synthesizing and degrading enzymes of compatible solutes, is proposed. Because the ion-induced activation/inhibition of enzymes is a fast and efficient process, it may represent a common strategy of microbes for adaptation to environments with fluctuating salinity.
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Sanz Smachetti ME, Coronel CD, Salerno GL, Curatti L. Sucrose-to-ethanol microalgae-based platform using seawater. ALGAL RES 2020. [DOI: 10.1016/j.algal.2019.101733] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023]
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19
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Thiel K, Patrikainen P, Nagy C, Fitzpatrick D, Pope N, Aro EM, Kallio P. Redirecting photosynthetic electron flux in the cyanobacterium Synechocystis sp. PCC 6803 by the deletion of flavodiiron protein Flv3. Microb Cell Fact 2019; 18:189. [PMID: 31690310 PMCID: PMC6833302 DOI: 10.1186/s12934-019-1238-2] [Citation(s) in RCA: 22] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/17/2019] [Accepted: 10/23/2019] [Indexed: 01/20/2023] Open
Abstract
Background Oxygen-evolving photoautotrophic organisms, like cyanobacteria, protect their photosynthetic machinery by a number of regulatory mechanisms, including alternative electron transfer pathways. Despite the importance in modulating the electron flux distribution between the photosystems, alternative electron transfer routes may compete with the solar-driven production of CO2-derived target chemicals in biotechnological systems under development. This work focused on engineered cyanobacterial Synechocystis sp. PCC 6803 strains, to explore possibilities to rescue excited electrons that would normally be lost to molecular oxygen by an alternative acceptor flavodiiron protein Flv1/3—an enzyme that is natively associated with transfer of electrons from PSI to O2, as part of an acclimation strategy towards varying environmental conditions. Results The effects of Flv1/3 inactivation by flv3 deletion were studied in respect to three alternative end-products, sucrose, polyhydroxybutyrate and glycogen, while the photosynthetic gas fluxes were monitored by Membrane Inlet Mass Spectrometry (MIMS) to acquire information on cellular carbon uptake, and the production and consumption of O2. The results demonstrated that a significant proportion of the excited electrons derived from photosynthetic water cleavage was lost to molecular oxygen via Flv1/3 in cells grown under high CO2, especially under high light intensities. In flv3 deletion strains these electrons could be re-routed to increase the relative metabolic flux towards the monitored target products, but the carbon distribution and the overall efficiency were determined by the light conditions and the genetic composition of the respective pathways. At the same time, the total photosynthetic capacity of the Δflv3 strains was systematically reduced, and accompanied by upregulation of oxidative glycolytic metabolism in respect to controls with the native Flv1/3 background. Conclusions The observed metabolic changes and respective production profiles were proposedly linked with the lack of Flv1/3-mediated electron transfer, and the associated decrease in the intracellular ATP/NADPH ratio, which is bound to affect the metabolic carbon partitioning in the flv3-deficient cells. While the deletion of flv3 could offer a strategy for enhancing the photosynthetic production of desired chemicals in cyanobacteria under specified conditions, the engineered target pathways have to be carefully selected to align with the intracellular redox balance of the cells.
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Affiliation(s)
- Kati Thiel
- Molecular Plant Biology, Department of Biochemistry, University of Turku, 20014, Turun Yliopisto, Finland
| | - Pekka Patrikainen
- Molecular Plant Biology, Department of Biochemistry, University of Turku, 20014, Turun Yliopisto, Finland
| | - Csaba Nagy
- Molecular Plant Biology, Department of Biochemistry, University of Turku, 20014, Turun Yliopisto, Finland
| | - Duncan Fitzpatrick
- Molecular Plant Biology, Department of Biochemistry, University of Turku, 20014, Turun Yliopisto, Finland
| | - Nicolas Pope
- Department of Future Technologies, University of Turku, 20014, Turun Yliopisto, Finland
| | - Eva-Mari Aro
- Molecular Plant Biology, Department of Biochemistry, University of Turku, 20014, Turun Yliopisto, Finland
| | - Pauli Kallio
- Molecular Plant Biology, Department of Biochemistry, University of Turku, 20014, Turun Yliopisto, Finland. .,, Itäinen Pitkäkatu 4 C, 20520, Turku, Finland.
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20
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Kirsch F, Klähn S, Hagemann M. Salt-Regulated Accumulation of the Compatible Solutes Sucrose and Glucosylglycerol in Cyanobacteria and Its Biotechnological Potential. Front Microbiol 2019; 10:2139. [PMID: 31572343 PMCID: PMC6753628 DOI: 10.3389/fmicb.2019.02139] [Citation(s) in RCA: 40] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/02/2019] [Accepted: 08/30/2019] [Indexed: 12/11/2022] Open
Abstract
Cyanobacteria are prokaryotes that can assimilate inorganic carbon via oxygenic photosynthesis, which results in the formation of organic compounds essentially from CO2, water, and light. Increasing concerns regarding the increase in atmospheric CO2 due to fossil energy usage fueled the idea of a photosynthesis-driven and CO2-neutral, i.e., cyanobacteria-based biotechnology. The ability of various cyanobacteria to tolerate high and/or fluctuating salinities attenuates the requirement of freshwater for their cultivation, which makes these organisms even more interesting regarding a sustainable utilization of natural resources. However, those applications require a detailed knowledge of the processes involved in salt acclimation. Here, we review the current state of our knowledge on the regulation of compatible solute accumulation in cyanobacteria. The model organism Synechocystis sp. PCC 6803 responds to increasing salinities mainly by the accumulation of glucosylglycerol (GG) and sucrose. After exposure toward increased salt concentrations, the accumulation of the main compatible solute GG is achieved by de novo synthesis. The key target of regulation is the enzyme GG-phosphate synthase (GgpS) and involves transcriptional, posttranscriptional, and biochemical mechanisms. Recently, the GG-degrading enzyme GG hydrolase A (GghA) was identified, which is particularly important for GG degradation during exposure to decreasing salinities. The inversely ion-regulated activities of GgpS and GghA could represent the main model for effectively tuning GG steady state levels according to external salinities. Similar to GG, the intracellular amount of sucrose is also salt-regulated and seems to be determined by the balance of sucrose synthesis via sucrose-phosphate synthase (Sps) and its degradation via invertase (Inv). In addition to their role as stress protectants, both compatible solutes also represent promising targets for biotechnology. Hence, the increasing knowledge on the regulation of compatible solute accumulation not only improves our understanding of the stress physiology of cyanobacteria but will also support their future biotechnological applications.
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Affiliation(s)
- Friedrich Kirsch
- Department of Plant Physiology, Institute for Biosciences, University of Rostock, Rostock, Germany
| | - Stephan Klähn
- Department of Solar Materials, Helmholtz-Centre for Environmental Research-UFZ, Leipzig, Germany
| | - Martin Hagemann
- Department of Plant Physiology, Institute for Biosciences, University of Rostock, Rostock, Germany
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21
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Qiao C, Zhang M, Luo Q, Lu X. Identification of two two-component signal transduction mutants with enhanced sucrose biosynthesis in Synechococcus elongatus PCC 7942. J Basic Microbiol 2019; 59:465-476. [PMID: 30802333 DOI: 10.1002/jobm.201800676] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/05/2018] [Revised: 01/13/2019] [Accepted: 01/25/2019] [Indexed: 12/19/2022]
Abstract
Metabolic engineering of the freshwater cyanobacterium Synechococcus elongatus PCC 7942 (Syn7942), synthesizing sucrose as the only compatible solute upon salt stress, has greatly improved its sucrose productivity. However, the signaling and regulatory mechanisms of this physiological process are still unknown. To know more about these aspects, a library of inactivation mutants for all 44 predicted signal transduction genes of Syn7942 was constructed. By evaluating sucrose production, two two-component signal transduction mutants Δ1125 and Δ1404, in which Synpcc7942_1125 and Synpcc7942_1404 was inactivated, respectively, were identified. They exhibited stably enhanced sucrose production, but the growth and the expression of sps encoding sucrose-phosphate synthase under salt stress were not affected, indicating that the corresponding signal transduction proteins do not regulate salt-induced sucrose synthesis by directly regulating sps expression. Moreover, the glycogen accumulation was enhanced in Δ1125 and Δ1404, and the salt stress-intensified photodamage of these mutants was also found to be relieved. These results indicated that the basic cell metabolisms such as glycogen metabolism and photosynthesis of the mutants were affected by gene inactivation, which might further affect salt-induced sucrose synthesis. Further studies on gene functions and signaling pathways or networks of Synpcc7942_1125 and Synpcc7942_1404 would reveal more details about the molecular bases for the observed phenotypes of Δ1125 and Δ1404.
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Affiliation(s)
- Cuncun Qiao
- Key Laboratory of Biofuels, Qingdao Institute of Bioenergy and Bioprocess Technology, Chinese Academy of Sciences, Qingdao, China.,Shandong Provincial Key Laboratory of Synthetic Biology, Qingdao Institute of Bioenergy and Bioprocess Technology, Chinese Academy of Sciences, Qingdao, China.,University of Chinese Academy of Sciences, Beijing, China
| | - Mingyi Zhang
- Key Laboratory of Biofuels, Qingdao Institute of Bioenergy and Bioprocess Technology, Chinese Academy of Sciences, Qingdao, China.,University of Chinese Academy of Sciences, Beijing, China.,Shandong Provincial Key Laboratory of Energy Genetics, Qingdao Institute of Bioenergy and Bioprocess Technology, Chinese Academy of Sciences, Qingdao, China
| | - Quan Luo
- Key Laboratory of Biofuels, Qingdao Institute of Bioenergy and Bioprocess Technology, Chinese Academy of Sciences, Qingdao, China.,Shandong Provincial Key Laboratory of Energy Genetics, Qingdao Institute of Bioenergy and Bioprocess Technology, Chinese Academy of Sciences, Qingdao, China
| | - Xuefeng Lu
- Key Laboratory of Biofuels, Qingdao Institute of Bioenergy and Bioprocess Technology, Chinese Academy of Sciences, Qingdao, China.,Shandong Provincial Key Laboratory of Synthetic Biology, Qingdao Institute of Bioenergy and Bioprocess Technology, Chinese Academy of Sciences, Qingdao, China.,Marine Biology and Biotechnology Laboratory, Qingdao National Laboratory for Marine Science and Technology, Aoshanwei, Qingdao, China
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Sanz Smachetti ME, Perez Cenci M, Salerno GL, Curatti L. Ethanol and protein production from minimally processed biomass of a genetically-modified cyanobacterium over-accumulating sucrose. ACTA ACUST UNITED AC 2019. [DOI: 10.1016/j.biteb.2019.01.019] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
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