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Brink DP, Mierke F, Norbeck J, Siewers V, Andlid T. Expanding the genetic toolbox of Rhodotorula toruloides by identification and validation of six novel promoters induced or repressed under nitrogen starvation. Microb Cell Fact 2023; 22:160. [PMID: 37598166 PMCID: PMC10440040 DOI: 10.1186/s12934-023-02175-2] [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: 05/02/2023] [Accepted: 08/09/2023] [Indexed: 08/21/2023] Open
Abstract
BACKGROUND The non-conventional yeast Rhodotorula toruloides is an emerging host organism in biotechnology by merit of its natural capacity to accumulate high levels of carotenoids and intracellular storage lipids from a variety of carbon sources. While the number of genetic engineering strategies that employ R. toruloides is increasing, the lack of genetic tools available for modification of this yeast is still limiting strain development. For instance, several strong, constitutive R. toruloides promoters have been characterized, but to date, only five inducible promoters have been identified. Although nitrogen-limited cultivation conditions are commonly used to induce lipid accumulation in this yeast, no promoters regulated by nitrogen starvation have been described for R. toruloides. RESULTS In this study, we used a combination of genomics and transcriptomics methods to identify novel R. toruloides promoter sequences that are either inducible or repressible by nitrogen starvation. RNA sequencing was used to assess gene expression in the recently isolated strain R. toruloides BOT-A2 during exponential growth and during nitrogen starvation, when cultivated with either glucose or xylose as the carbon source. The genome of BOT-A2 was sequenced using a combination of long- and short-read sequencing and annotated with support of the RNAseq data. Differential expression analysis was used to identify genes with a |log2 fold change|≥ 2 when comparing their expression during nitrogen depletion to that during exponential growth. The promoter regions from 16 of these genes were evaluated for their ability to drive the expression of a fluorescent reporter gene. Three promoters that were clearly upregulated under nitrogen starvation and three that were downregulated were selected and further characterized. One promoter, derived from gene RTBOTA2_003877, was found to function like an on-off switch, as it was only upregulated under full nitrogen depletion and downregulated in the presence of the nitrogen source. CONCLUSIONS Six new R. toruloides promoters that were either upregulated or downregulated under nitrogen-starvation were identified. These substantially contribute to the available promoters when engineering this organism and are foreseen to be particularly useful for future engineering strategies requiring specific regulation of target genes in accordance with nitrogen availability.
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Affiliation(s)
- Daniel P Brink
- Systems and Synthetic Biology, Department of Life Sciences, Chalmers University of Technology, Gothenburg, Sweden
- Applied Microbiology, Department of Chemistry, Lund University, Lund, Sweden
| | - Friederike Mierke
- Systems and Synthetic Biology, Department of Life Sciences, Chalmers University of Technology, Gothenburg, Sweden
- Food and Nutrition Science, Department of Life Sciences, Chalmers University of Technology, Gothenburg, Sweden
| | - Joakim Norbeck
- Systems and Synthetic Biology, Department of Life Sciences, Chalmers University of Technology, Gothenburg, Sweden
| | - Verena Siewers
- Systems and Synthetic Biology, Department of Life Sciences, Chalmers University of Technology, Gothenburg, Sweden.
- The Novo Nordisk Foundation Center for Biosustainability, Technical University of Denmark, Lyngby, Denmark.
| | - Thomas Andlid
- Food and Nutrition Science, Department of Life Sciences, Chalmers University of Technology, Gothenburg, Sweden
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2
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Adamczyk PA, Coradetti ST, Gladden JM. Non-canonical D-xylose and L-arabinose metabolism via D-arabitol in the oleaginous yeast Rhodosporidium toruloides. Microb Cell Fact 2023; 22:145. [PMID: 37537595 PMCID: PMC10398940 DOI: 10.1186/s12934-023-02126-x] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/20/2023] [Accepted: 06/17/2023] [Indexed: 08/05/2023] Open
Abstract
R. toruloides is an oleaginous yeast, with diverse metabolic capacities and high tolerance for inhibitory compounds abundant in plant biomass hydrolysates. While R. toruloides grows on several pentose sugars and alcohols, further engineering of the native pathway is required for efficient conversion of biomass-derived sugars to higher value bioproducts. A previous high-throughput study inferred that R. toruloides possesses a non-canonical L-arabinose and D-xylose metabolism proceeding through D-arabitol and D-ribulose. In this study, we present a combination of genetic and metabolite data that refine and extend that model. Chiral separations definitively illustrate that D-arabitol is the enantiomer that accumulates under pentose metabolism. Deletion of putative D-arabitol-2-dehydrogenase (RTO4_9990) results in > 75% conversion of D-xylose to D-arabitol, and is growth-complemented on pentoses by heterologous xylulose kinase expression. Deletion of putative D-ribulose kinase (RTO4_14368) arrests all growth on any pentose tested. Analysis of several pentose dehydrogenase mutants elucidates a complex pathway with multiple enzymes mediating multiple different reactions in differing combinations, from which we also inferred a putative L-ribulose utilization pathway. Our results suggest that we have identified enzymes responsible for the majority of pathway flux, with additional unknown enzymes providing accessory activity at multiple steps. Further biochemical characterization of the enzymes described here will enable a more complete and quantitative understanding of R. toruloides pentose metabolism. These findings add to a growing understanding of the diversity and complexity of microbial pentose metabolism.
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Affiliation(s)
- Paul A Adamczyk
- Agile Biofoundry, Emeryville, CA, USA
- Sandia National Laboratories, Livermore, CA, USA
| | - Samuel T Coradetti
- Agile Biofoundry, Emeryville, CA, USA
- Sandia National Laboratories, Livermore, CA, USA
- United States Department of Agriculture, Agricultural Research Service, Ithaca, NY, USA
| | - John M Gladden
- Agile Biofoundry, Emeryville, CA, USA.
- Sandia National Laboratories, Livermore, CA, USA.
- Joint BioEnergy Institute, Emeryville, CA, USA.
- Sandia National Laboratories, DOE Agile Biofoundry, 5885 Hollis Street, Fourth Floor, Emeryville, CA, 94608, USA.
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3
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Yu Y, Shi S. Development and Perspective of Rhodotorula toruloides as an Efficient Cell Factory. JOURNAL OF AGRICULTURAL AND FOOD CHEMISTRY 2023; 71:1802-1819. [PMID: 36688927 DOI: 10.1021/acs.jafc.2c07361] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/17/2023]
Abstract
Rhodotorula toruloides is receiving significant attention as a novel cell factory because of its high production of lipids and carotenoids, fast growth and high cell density, as well as the ability to utilize a wide variety of substrates. These attractive traits of R. toruloides make it possible to become a low-cost producer that can be engineered for the production of various fuels and chemicals. However, the lack of understanding and genetic engineering tools impedes its metabolic engineering applications. A number of research efforts have been devoted to filling these gaps. This review focuses on recent developments in genetic engineering tools, advances in systems biology for improved understandings, and emerging engineered strains for metabolic engineering applications. Finally, future trends and barriers in developing R. toruloides as a cell factory are also discussed.
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Affiliation(s)
- Yi Yu
- Beijing Advanced Innovation Center for Soft Matter Science and Engineering, College of Life Science and Technology, Beijing University of Chemical Technology, Beijing 100029, China
| | - Shuobo Shi
- Beijing Advanced Innovation Center for Soft Matter Science and Engineering, College of Life Science and Technology, Beijing University of Chemical Technology, Beijing 100029, China
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4
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Peltonen KE, Richard P. Identification of a D-galacturonate reductase efficiently using NADH as a cofactor. BIOTECHNOLOGY REPORTS 2022; 35:e00744. [PMID: 35711324 PMCID: PMC9192788 DOI: 10.1016/j.btre.2022.e00744] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 03/15/2022] [Revised: 05/23/2022] [Accepted: 05/31/2022] [Indexed: 11/29/2022]
Abstract
D-galacturonate reductase EC 1.1.1.365 uses NADH efficiently. Identification of the D-galacturonate reductase gene in Euglena gracilis. A useful tool for the engineering of a pathway for efficient fermentation of D-galacturonic acid.
D-galacturonate reductases are catalysing the reversible reduction of D-galacturonate to L-galactonate using NAD(P)H as a cofactor. The enzymes are part of two different pathways. One pathway is the fungal pathway for the catabolism of the main compound of pectin, D-galacturonate. The other pathway is a a pathway in plants for L-ascorbic acid synthesis. The previously described naturally occurring enzymes preferably use NADPH as a cofactor. Although certain D-galacturonate reductases, such as the reductases from Aspergillus niger or Euglena gracilis also accept NADH, their activity is significantly higher with NADPH. We identified in E. gracilis a gene, called gaa1, coding for a D-galacturonate reductase with similar activities with NADH and NADPH. It is potentially useful for the metabolic engineering of microbes to make use of pectin rich biomass.
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5
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Zhao Y, Song B, Li J, Zhang J. Rhodotorula toruloides: an ideal microbial cell factory to produce oleochemicals, carotenoids, and other products. World J Microbiol Biotechnol 2021; 38:13. [PMID: 34873661 DOI: 10.1007/s11274-021-03201-4] [Citation(s) in RCA: 17] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/11/2021] [Accepted: 11/29/2021] [Indexed: 12/20/2022]
Abstract
Requirement of clean energy sources urges us to find substitutes for fossil fuels. Microorganisms provide an option to produce feedstock for biofuel production by utilizing inexpensive, renewable biomass. Rhodotorula toruloides (Rhodosporidium toruloides), a non-conventional oleaginous yeast, can accumulate intracellular lipids (single cell oil, SCO) more than 70% of its cell dry weight. At present, the SCO-based biodiesel is not a price-competitive fuel to the petroleum diesel. Many efforts are made to cut the cost of SCO by strengthening the performance of genetically modified R. toruloides strains and by valorization of low-cost biomass, including crude glycerol, lignocellulosic hydrolysates, food and agro waste, wastewater, and volatile fatty acids. Besides, optimization of fermentation and SCO recovery processes are carefully studied as well. Recently, new R. toruloides strains are developed via metabolic engineering and synthetic biology methods to produce value-added chemicals, such as sesquiterpenes, fatty acid esters, fatty alcohols, carotenoids, and building block chemicals. This review summarizes recent advances in the main aspects of R. toruloides studies, namely, construction of strains with new traits, valorization of low-cost biomass, process detection and optimization, and product recovery. In general, R. toruloides is a promising microbial cell factory for production of biochemicals.
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Affiliation(s)
- Yu Zhao
- Center for Molecular Metabolism, Nanjing University of Science & Technology, 200 Xiaolingwei Street, Nanjing, 210094, China.,Key Laboratory of Metabolic Engineering and Biosynthesis Technology of Ministry of Industry and Information Technology, Nanjing University of Science and Technology, 200 Xiaolingwei Street, Nanjing, 210094, China
| | - Baocai Song
- Center for Molecular Metabolism, Nanjing University of Science & Technology, 200 Xiaolingwei Street, Nanjing, 210094, China.,Key Laboratory of Metabolic Engineering and Biosynthesis Technology of Ministry of Industry and Information Technology, Nanjing University of Science and Technology, 200 Xiaolingwei Street, Nanjing, 210094, China
| | - Jing Li
- Center for Molecular Metabolism, Nanjing University of Science & Technology, 200 Xiaolingwei Street, Nanjing, 210094, China. .,Key Laboratory of Metabolic Engineering and Biosynthesis Technology of Ministry of Industry and Information Technology, Nanjing University of Science and Technology, 200 Xiaolingwei Street, Nanjing, 210094, China.
| | - Jianfa Zhang
- Center for Molecular Metabolism, Nanjing University of Science & Technology, 200 Xiaolingwei Street, Nanjing, 210094, China.,Key Laboratory of Metabolic Engineering and Biosynthesis Technology of Ministry of Industry and Information Technology, Nanjing University of Science and Technology, 200 Xiaolingwei Street, Nanjing, 210094, China
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6
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Lad BC, Coleman SM, Alper HS. Microbial valorization of underutilized and nonconventional waste streams. J Ind Microbiol Biotechnol 2021; 49:6371101. [PMID: 34529075 PMCID: PMC9118980 DOI: 10.1093/jimb/kuab056] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/13/2021] [Accepted: 09/14/2021] [Indexed: 12/12/2022]
Abstract
The growing burden of waste disposal coupled with natural resource scarcity has renewed interest in the remediation, valorization, and/or repurposing of waste. Traditional approaches such as composting, anaerobic digestion, use in fertilizers or animal feed, or incineration for energy production extract very little value out of these waste streams. In contrast, waste valorization into fuels and other biochemicals via microbial fermentation is an area of growing interest. In this review, we discuss microbial valorization of nonconventional, aqueous waste streams such as food processing effluents, wastewater streams, and other industrial wastes. We categorize these waste streams as carbohydrate-rich food wastes, lipid-rich wastes, and other industrial wastes. Recent advances in microbial valorization of these nonconventional waste streams are highlighted, along with a discussion of the specific challenges and opportunities associated with impurities, nitrogen content, toxicity, and low productivity.
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Affiliation(s)
- Beena C Lad
- Department of Molecular Biosciences, The University of Texas at Austin, 100 East 24th Street Stop A5000, Austin, TX 78712 USA
| | - Sarah M Coleman
- McKetta Department of Chemical Engineering, The University of Texas at Austin, 200 E Dean Keeton St. Stop C0400, Austin, TX 78712 USA
| | - Hal S Alper
- McKetta Department of Chemical Engineering, The University of Texas at Austin, 200 E Dean Keeton St. Stop C0400, Austin, TX 78712 USA.,Institute for Cellular and Molecular Biology, The University of Texas at Austin, 2500 Speedway Avenue, Austin, Texas 78712 USA
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7
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Developing Functional Genomics Platforms for Fungi. mSystems 2021; 6:e0073021. [PMID: 34427501 PMCID: PMC8407244 DOI: 10.1128/msystems.00730-21] [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] [Indexed: 11/20/2022] Open
Abstract
Fungi are responsible for diseases that result in the deaths of over a million individuals each year and devastating crop infestations that threaten global food supplies. However, outside of a select few model organisms, the majority of fungal genes are uncharacterized. The roles of these genes in the biology of the organism, pathogenesis, and mediating interactions with the environment and other microbes are unknown. Historically, fungal gene characterization has primarily relied on classical genetic screens. However, advances in sequencing technology have enabled more rapid methods of gene functional characterization. Large-scale transcriptional profiling projects are one solution to generating hypotheses about fungal gene function. Together with other 'omics techniques and newer tools that enable massively parallel mutant screens, knowledge of fungal gene function will be substantially improved. Understanding the function of fungal genes will be instrumental in increasing global food security, protecting ecosystems, and improving health outcomes.
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8
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Oliveira J, Antunes M, Godinho CP, Teixeira MC, Sá-Correia I, Monteiro PT. From a genome assembly to full regulatory network prediction: the case study of Rhodotorula toruloides putative Haa1-regulon. BMC Bioinformatics 2021; 22:399. [PMID: 34376148 PMCID: PMC8353774 DOI: 10.1186/s12859-021-04312-3] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/07/2020] [Accepted: 07/30/2021] [Indexed: 12/19/2022] Open
Abstract
Numerous genomes are sequenced and made available to the community through the NCBI portal. However, and, unlike what happens for gene function annotation, annotation of promoter sequences and the underlying prediction of regulatory associations is mostly unavailable, severely limiting the ability to interpret genome sequences in a functional genomics perspective. Here we present an approach where one can download a genome of interest from NCBI in the GenBank Flat File (.gbff) format and, with a minimum set of commands, have all the information parsed, organized and made available through the platform web interface. Also, the new genomes are compared with a given genome of reference in search of homologous genes, shared regulatory elements and predicted transcription associations. We present this approach within the context of Community YEASTRACT of the YEASTRACT + portal, thus benefiting from immediate access to all the comparative genomics queries offered in the YEASTRACT + portal. Besides the yeast community, other communities can install the platform independently, without any constraints. In this work, we exemplify the usefulness of the presented tool, within Community YEASTRACT, in constructing a dedicated database and analysing the genome of the highly promising oleaginous red yeast species Rhodotorula toruloides currently poorly studied at the genome and transcriptome levels and with limited genome editing tools. Regulatory prediction is based on the conservation of promoter sequences and available regulatory networks. The case-study examined is focused on the Haa1 transcription factor—a key regulator of yeast resistance to acetic acid, an important inhibitor of industrial bioconversion of lignocellulosic hydrolysates. The new tool described here led to the prediction of a RtHaa1 regulon with expected impact in the optimization of R. toruloides robustness for lignocellulosic and pectin-rich residue biorefinery processes.
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Affiliation(s)
| | - Miguel Antunes
- iBB - Institute for Bioengineering and Biosciences/ i4HB - Associate Laboratory Institute for Health and Bioeconomy, Instituto Superior Técnico, Universidade de Lisboa, Lisbon, Portugal.,Department of Bioengineering, Instituto Superior Técnico, Universidade de Lisboa, Lisbon, Portugal
| | - Claudia P Godinho
- iBB - Institute for Bioengineering and Biosciences/ i4HB - Associate Laboratory Institute for Health and Bioeconomy, Instituto Superior Técnico, Universidade de Lisboa, Lisbon, Portugal
| | - Miguel C Teixeira
- iBB - Institute for Bioengineering and Biosciences/ i4HB - Associate Laboratory Institute for Health and Bioeconomy, Instituto Superior Técnico, Universidade de Lisboa, Lisbon, Portugal.,Department of Bioengineering, Instituto Superior Técnico, Universidade de Lisboa, Lisbon, Portugal
| | - Isabel Sá-Correia
- iBB - Institute for Bioengineering and Biosciences/ i4HB - Associate Laboratory Institute for Health and Bioeconomy, Instituto Superior Técnico, Universidade de Lisboa, Lisbon, Portugal.,Department of Bioengineering, Instituto Superior Técnico, Universidade de Lisboa, Lisbon, Portugal
| | - Pedro T Monteiro
- INESC-ID, Lisbon, Portugal. .,Department of Computer Science and Engineering, Instituto Superior Técnico (IST), Universidade de Lisboa, Lisbon, Portugal.
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9
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Martins LC, Palma M, Angelov A, Nevoigt E, Liebl W, Sá-Correia I. Complete Utilization of the Major Carbon Sources Present in Sugar Beet Pulp Hydrolysates by the Oleaginous Red Yeasts Rhodotorula toruloides and R. mucilaginosa. J Fungi (Basel) 2021; 7:jof7030215. [PMID: 33802726 PMCID: PMC8002571 DOI: 10.3390/jof7030215] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/22/2021] [Revised: 03/13/2021] [Accepted: 03/15/2021] [Indexed: 12/12/2022] Open
Abstract
Agro-industrial residues are low-cost carbon sources (C-sources) for microbial growth and production of value-added bioproducts. Among the agro-industrial residues available, those rich in pectin are generated in high amounts worldwide from the sugar industry or the industrial processing of fruits and vegetables. Sugar beet pulp (SBP) hydrolysates contain predominantly the neutral sugars d-glucose, l-arabinose and d-galactose, and the acidic sugar d-galacturonic acid. Acetic acid is also present at significant concentrations since the d-galacturonic acid residues are acetylated. In this study, we have examined and optimized the performance of a Rhodotorula mucilaginosa strain, isolated from SBP and identified at the molecular level during this work. This study was extended to another oleaginous red yeast species, R. toruloides, envisaging the full utilization of the C-sources from SBP hydrolysate (at pH 5.0). The dual role of acetic acid as a carbon and energy source and as a growth and metabolism inhibitor was examined. Acetic acid prevented the catabolism of d-galacturonic acid and l-arabinose after the complete use of the other C-sources. However, d-glucose and acetic acid were simultaneously and efficiently metabolized, followed by d-galactose. SBP hydrolysate supplementation with amino acids was crucial to allow d-galacturonic acid and l-arabinose catabolism. SBP valorization through the production of lipids and carotenoids by Rhodotorula strains, supported by complete catabolism of the major C-sources present, looks promising for industrial implementation.
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Affiliation(s)
- Luís C. Martins
- iBB—Institute for Bioengineering and Biosciences/i4HB—Associate Laboratory Institute for Health and Bioeconomy, Instituto Superior Técnico, Universidade de Lisboa, 1049-001 Lisbon, Portugal; (L.C.M.); (M.P.)
- Department of Bioengineering, Instituto Superior Técnico, Universidade de Lisboa, 1049-001 Lisbon, Portugal
| | - Margarida Palma
- iBB—Institute for Bioengineering and Biosciences/i4HB—Associate Laboratory Institute for Health and Bioeconomy, Instituto Superior Técnico, Universidade de Lisboa, 1049-001 Lisbon, Portugal; (L.C.M.); (M.P.)
- Department of Bioengineering, Instituto Superior Técnico, Universidade de Lisboa, 1049-001 Lisbon, Portugal
| | - Angel Angelov
- TUM School of Life Sciences, Technical University of Munich, 85354 Freising, Germany; (A.A.); (W.L.)
| | - Elke Nevoigt
- Department of Life Sciences and Chemistry, Jacobs University Bremen GmbH, Campus Ring 1, 28759 Bremen, Germany;
| | - Wolfgang Liebl
- TUM School of Life Sciences, Technical University of Munich, 85354 Freising, Germany; (A.A.); (W.L.)
| | - Isabel Sá-Correia
- iBB—Institute for Bioengineering and Biosciences/i4HB—Associate Laboratory Institute for Health and Bioeconomy, Instituto Superior Técnico, Universidade de Lisboa, 1049-001 Lisbon, Portugal; (L.C.M.); (M.P.)
- Department of Bioengineering, Instituto Superior Técnico, Universidade de Lisboa, 1049-001 Lisbon, Portugal
- Correspondence:
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10
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Jeong D, Park H, Jang BK, Ju Y, Shin MH, Oh EJ, Lee EJ, Kim SR. Recent advances in the biological valorization of citrus peel waste into fuels and chemicals. BIORESOURCE TECHNOLOGY 2021; 323:124603. [PMID: 33406467 DOI: 10.1016/j.biortech.2020.124603] [Citation(s) in RCA: 33] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/31/2020] [Revised: 12/18/2020] [Accepted: 12/20/2020] [Indexed: 06/12/2023]
Abstract
In the quest to reduce global food loss and waste, fruit processing wastes, particularly citrus peel waste (CPW), have emerged as a promising and sustainable option for biorefinery without competing with human foods and animal feeds. CPW is largely produced and, as recent studies suggest, has the industrial potential of biological valorization into fuels and chemicals. In this review, the promising aspects of CPW as an alternative biomass were highlighted, focusing on its low lignin content. In addition, specific technical difficulties in fermenting CPW are described, highlighting that citrus peel is high in pectin that consist of non-fermentable sugars, mainly galacturonic acid. Last, recent advances in the metabolic engineering of yeast and other microbial strains that ferment CPW-derived sugars to produce value-added products, such as ethanol and mucic acid, are summarized. For industrially viable CPW-based biorefinery, more studies are needed to improve fermentation efficiency and to diversify product profiles.
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Affiliation(s)
- Deokyeol Jeong
- School of Food Science and Biotechnology, Kyungpook National University, Daegu 41566, South Korea
| | - Heeyoung Park
- School of Food Science and Biotechnology, Kyungpook National University, Daegu 41566, South Korea
| | - Byeong-Kwan Jang
- School of Food Science and Biotechnology, Kyungpook National University, Daegu 41566, South Korea
| | - YeBin Ju
- School of Food Science and Biotechnology, Kyungpook National University, Daegu 41566, South Korea
| | - Min Hye Shin
- Research Institute of Agriculture and Life Sciences, Seoul National University, Seoul 08826, South Korea
| | - Eun Joong Oh
- Department of Food Science, Purdue University, West Lafayette, IN 47907, USA
| | - Eun Jung Lee
- Department of Chemical Engineering, School of Applied Chemical Engineering, Kyungpook National University, Daegu, South Korea
| | - Soo Rin Kim
- School of Food Science and Biotechnology, Kyungpook National University, Daegu 41566, South Korea.
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11
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Lee JW, Yook S, Koh H, Rao CV, Jin YS. Engineering xylose metabolism in yeasts to produce biofuels and chemicals. Curr Opin Biotechnol 2020; 67:15-25. [PMID: 33246131 DOI: 10.1016/j.copbio.2020.10.012] [Citation(s) in RCA: 23] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/17/2020] [Revised: 10/18/2020] [Accepted: 10/25/2020] [Indexed: 10/22/2022]
Abstract
Xylose is the second most abundant sugar in lignocellulosic biomass. Efficient and rapid xylose utilization is essential for the economic bioconversion of lignocellulosic biomass into value-added products. Building on previous pathway engineering efforts to enable xylose fermentation in Saccharomyces cerevisiae, recent work has focused on reprogramming regulatory networks to enhance xylose utilization by engineered S. cerevisiae. Also, potential benefits of using xylose for the production of various value-added products have been demonstrated. With increasing needs of lipid-derived bioproducts, activation and enhancement of xylose metabolism in oleaginous yeasts have been attempted. This review highlights recent progress of metabolic engineering to achieve efficient and rapid xylose utilization by S. cerevisiae and oleaginous yeasts, such as Yarrowia lipolytica, Rhodosporidium toruloides, and Lipomyces starkeyi.
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Affiliation(s)
- Jae Won Lee
- Department of Food Science and Human Nutrition, University of Illinois at Urbana-Champaign, Urbana, IL 61801, USA; Carl R. Woese Institute for Genomic Biology, University of Illinois at Urbana-Champaign, Urbana, IL 61801, USA
| | - Sangdo Yook
- Department of Food Science and Human Nutrition, University of Illinois at Urbana-Champaign, Urbana, IL 61801, USA; Carl R. Woese Institute for Genomic Biology, University of Illinois at Urbana-Champaign, Urbana, IL 61801, USA
| | - Hyungi Koh
- Carl R. Woese Institute for Genomic Biology, University of Illinois at Urbana-Champaign, Urbana, IL 61801, USA
| | - Christopher V Rao
- Carl R. Woese Institute for Genomic Biology, University of Illinois at Urbana-Champaign, Urbana, IL 61801, USA; Department of Chemical and Biomolecular Engineering, University of Illinois at Urbana-Champaign, Urbana, IL 61801, USA
| | - Yong-Su Jin
- Department of Food Science and Human Nutrition, University of Illinois at Urbana-Champaign, Urbana, IL 61801, USA; Carl R. Woese Institute for Genomic Biology, University of Illinois at Urbana-Champaign, Urbana, IL 61801, USA.
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12
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Engineering cofactor supply and NADH-dependent D-galacturonic acid reductases for redox-balanced production of L-galactonate in Saccharomyces cerevisiae. Sci Rep 2020; 10:19021. [PMID: 33149263 PMCID: PMC7642425 DOI: 10.1038/s41598-020-75926-5] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/06/2020] [Accepted: 10/20/2020] [Indexed: 12/15/2022] Open
Abstract
D-Galacturonic acid (GalA) is the major constituent of pectin-rich biomass, an abundant and underutilized agricultural byproduct. By one reductive step catalyzed by GalA reductases, GalA is converted to the polyhydroxy acid L-galactonate (GalOA), the first intermediate of the fungal GalA catabolic pathway, which also has interesting properties for potential applications as an additive to nutrients and cosmetics. Previous attempts to establish the production of GalOA or the full GalA catabolic pathway in Saccharomyces cerevisiae proved challenging, presumably due to the inefficient supply of NADPH, the preferred cofactor of GalA reductases. Here, we tested this hypothesis by coupling the reduction of GalA to the oxidation of the sugar alcohol sorbitol that has a higher reduction state compared to glucose and thereby yields the necessary redox cofactors. By choosing a suitable sorbitol dehydrogenase, we designed yeast strains in which the sorbitol metabolism yields a "surplus" of either NADPH or NADH. By biotransformation experiments in controlled bioreactors, we demonstrate a nearly complete conversion of consumed GalA into GalOA and a highly efficient utilization of the co-substrate sorbitol in providing NADPH. Furthermore, we performed structure-guided mutagenesis of GalA reductases to change their cofactor preference from NADPH towards NADH and demonstrated their functionality by the production of GalOA in combination with the NADH-yielding sorbitol metabolism. Moreover, the engineered enzymes enabled a doubling of GalOA yields when glucose was used as a co-substrate. This significantly expands the possibilities for metabolic engineering of GalOA production and valorization of pectin-rich biomass in general.
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Thieme N, Panitz JC, Held C, Lewandowski B, Schwarz WH, Liebl W, Zverlov V. Milling byproducts are an economically viable substrate for butanol production using clostridial ABE fermentation. Appl Microbiol Biotechnol 2020; 104:8679-8689. [PMID: 32915256 PMCID: PMC7502454 DOI: 10.1007/s00253-020-10882-8] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/19/2020] [Revised: 08/14/2020] [Accepted: 09/02/2020] [Indexed: 12/14/2022]
Abstract
Butanol is a platform chemical that is utilized in a wide range of industrial products and is considered a suitable replacement or additive to liquid fuels. So far, it is mainly produced through petrochemical routes. Alternative production routes, for example through biorefinery, are under investigation but are currently not at a market competitive level. Possible alternatives, such as acetone-butanol-ethanol (ABE) fermentation by solventogenic clostridia are not market-ready to this day either, because of their low butanol titer and the high costs of feedstocks. Here, we analyzed wheat middlings and wheat red dog, two wheat milling byproducts available in large quantities, as substrates for clostridial ABE fermentation. We could identify ten strains that exhibited good butanol yields on wheat red dog. Two of the best ABE producing strains, Clostridium beijerinckii NCIMB 8052 and Clostridium diolis DSM 15410, were used to optimize a laboratory-scale fermentation process. In addition, enzymatic pretreatment of both milling byproducts significantly enhanced ABE production rates of the strains C. beijerinckii NCIMB 8052 and C. diolis DSM 15410. Finally, a profitability analysis was performed for small- to mid-scale ABE fermentation plants that utilize enzymatically pretreated wheat red dog as substrate. The estimations show that such a plant could be commercially successful.Key points• Wheat milling byproducts are suitable substrates for clostridial ABE fermentation.• Enzymatic pretreatment of wheat red dog and middlings increases ABE yield.• ABE fermentation plants using wheat red dog as substrate are economically viable. Graphical abstract.
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Affiliation(s)
- Nils Thieme
- Technical University of Munich, Emil-Ramann-Str. 4, 85354, Freising, Germany
| | - Johanna C Panitz
- Technical University of Munich, Emil-Ramann-Str. 4, 85354, Freising, Germany
- Technical University of Munich, Weihenstephaner Berg 3, 85354, Freising, Germany
| | - Claudia Held
- Technical University of Munich, Emil-Ramann-Str. 4, 85354, Freising, Germany
- TDK Electronics AG, Rosenheimer Str. 141e, 81671, Munich, Germany
| | - Birgit Lewandowski
- Fritzmeier Umwelttechnik GmbH & Co KG, Dorfstraße 7, 85653, Aying, Germany
- Electrochaea GmbH, Semmelweisstrasse 3, 82152, Planegg, Germany
| | - Wolfgang H Schwarz
- Technical University of Munich, Emil-Ramann-Str. 4, 85354, Freising, Germany
- aspratis GmbH, Huebnerstrasse 11, 80637, Munich, Germany
| | - Wolfgang Liebl
- Technical University of Munich, Emil-Ramann-Str. 4, 85354, Freising, Germany
| | - Vladimir Zverlov
- Technical University of Munich, Emil-Ramann-Str. 4, 85354, Freising, Germany.
- Institute of Molecular Genetics, RAS, Kurchatov Sq 2, 123128, Moscow, Russia.
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Wen Z, Zhang S, Odoh CK, Jin M, Zhao ZK. Rhodosporidium toruloides - A potential red yeast chassis for lipids and beyond. FEMS Yeast Res 2020; 20:foaa038. [PMID: 32614407 PMCID: PMC7334043 DOI: 10.1093/femsyr/foaa038] [Citation(s) in RCA: 62] [Impact Index Per Article: 15.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/10/2020] [Accepted: 06/12/2020] [Indexed: 12/19/2022] Open
Abstract
The red yeast Rhodosporidium toruloides naturally produces microbial lipids and carotenoids. In the past decade or so, many studies demonstrated R. toruloides as a promising platform for lipid production owing to its diverse substrate appetites, robust stress resistance and other favorable features. Also, significant progresses have been made in genome sequencing, multi-omic analysis and genome-scale modeling, thus illuminating the molecular basis behind its physiology, metabolism and response to environmental stresses. At the same time, genetic parts and tools are continuously being developed to manipulate this distinctive organism. Engineered R. toruloides strains are emerging for enhanced production of conventional lipids, functional lipids as well as other interesting metabolites. This review updates those progresses and highlights future directions for advanced biotechnological applications.
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Affiliation(s)
- Zhiqiang Wen
- School of Environmental and Biological Engineering, Nanjing University of Science & Technology, 200 Xiaolingwei St, Nanjing 210094, China
| | - Sufang Zhang
- Laboratory of Biotechnology, Dalian Institute of Chemical Physics, CAS, 457 Zhongshan Rd, Dalian 116023, China
| | - Chuks Kenneth Odoh
- Laboratory of Biotechnology, Dalian Institute of Chemical Physics, CAS, 457 Zhongshan Rd, Dalian 116023, China
| | - Mingjie Jin
- School of Environmental and Biological Engineering, Nanjing University of Science & Technology, 200 Xiaolingwei St, Nanjing 210094, China
| | - Zongbao K Zhao
- Laboratory of Biotechnology, Dalian Institute of Chemical Physics, CAS, 457 Zhongshan Rd, Dalian 116023, China
- Dalian Key Laboratory of Energy Biotechnology, Dalian Institute of Chemical Physics, CAS, 457 Zhongshan Rd, Dalian 116023, China
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Martins LC, Monteiro CC, Semedo PM, Sá-Correia I. Valorisation of pectin-rich agro-industrial residues by yeasts: potential and challenges. Appl Microbiol Biotechnol 2020; 104:6527-6547. [PMID: 32474799 PMCID: PMC7347521 DOI: 10.1007/s00253-020-10697-7] [Citation(s) in RCA: 26] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/20/2020] [Revised: 05/08/2020] [Accepted: 05/19/2020] [Indexed: 01/29/2023]
Abstract
Pectin-rich agro-industrial residues are feedstocks with potential for sustainable biorefineries. They are generated in high amounts worldwide from the industrial processing of fruits and vegetables. The challenges posed to the industrial implementation of efficient bioprocesses are however manyfold and thoroughly discussed in this review paper, mainly at the biological level. The most important yeast cell factory platform for advanced biorefineries is currently Saccharomyces cerevisiae, but this yeast species cannot naturally catabolise the main sugars present in pectin-rich agro-industrial residues hydrolysates, in particular d-galacturonic acid and l-arabinose. However, there are non-Saccharomyces species (non-conventional yeasts) considered advantageous alternatives whenever they can express highly interesting metabolic pathways, natively assimilate a wider range of carbon sources or exhibit higher tolerance to relevant bioprocess-related stresses. For this reason, the interest in non-conventional yeasts for biomass-based biorefineries is gaining momentum. This review paper focuses on the valorisation of pectin-rich residues by exploring the potential of yeasts that exhibit vast metabolic versatility for the efficient use of the carbon substrates present in their hydrolysates and high robustness to cope with the multiple stresses encountered. The major challenges and the progresses made related with the isolation, selection, sugar catabolism, metabolic engineering and use of non-conventional yeasts and S. cerevisiae-derived strains for the bioconversion of pectin-rich residue hydrolysates are discussed. The reported examples of value-added products synthesised by different yeasts using pectin-rich residues are reviewed.Key Points • Review of the challenges and progresses made on the bioconversion of pectin-rich residues by yeasts. • Catabolic pathways for the main carbon sources present in pectin-rich residues hydrolysates. • Multiple stresses with potential to affect bioconversion productivity. • Yeast metabolic engineering to improve pectin-rich residues bioconversion. |
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Affiliation(s)
- Luís C Martins
- iBB - Institute for Bioengineering and Biosciences, Instituto Superior Técnico, Universidade de Lisboa, Lisbon, Portugal
- Department of Bioengineering, Instituto Superior Técnico, Universidade de Lisboa, Lisbon, Portugal
| | - Catarina C Monteiro
- iBB - Institute for Bioengineering and Biosciences, Instituto Superior Técnico, Universidade de Lisboa, Lisbon, Portugal
| | - Paula M Semedo
- iBB - Institute for Bioengineering and Biosciences, Instituto Superior Técnico, Universidade de Lisboa, Lisbon, Portugal
| | - Isabel Sá-Correia
- iBB - Institute for Bioengineering and Biosciences, Instituto Superior Técnico, Universidade de Lisboa, Lisbon, Portugal.
- Department of Bioengineering, Instituto Superior Técnico, Universidade de Lisboa, Lisbon, Portugal.
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