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Andrade Silva CAD, Oka ML, da Silva PGP, Honma JM, Leite RSR, Fonseca GG. Physiological evaluation of yeast strains under anaerobic conditions using glucose, fructose, or sucrose as the carbon source. J Biosci Bioeng 2024; 137:420-428. [PMID: 38493064 DOI: 10.1016/j.jbiosc.2024.02.003] [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: 07/27/2023] [Revised: 01/26/2024] [Accepted: 02/14/2024] [Indexed: 03/18/2024]
Abstract
The aim of this study was to evaluate the physiology of 13 yeast strains by assessing their kinetic parameters under anaerobic conditions. They included Saccharomyces cerevisiae CAT-1 and 12 isolated yeasts from different regions in Brazil. The study aimed to enhance understanding of the metabolism of these strains for more effective applications. Measurements included quantification of sugars, ethanol, glycerol, and organic acids. Various kinetic parameters were analyzed, such as specific substrate utilization rate (qS), maximum specific growth rate (μmax), doubling time, biomass yield, product yield, maximum cell concentration, ethanol productivity (PEth), biomass productivity, and CO2 concentration. S. cerevisiae CAT-1 exhibited the highest values in glucose for μmax (0.35 h-1), qS (3.06 h-1), and PEth (0.69 gEth L-1 h-1). Candida parapsilosis Recol 37 did not fully consume the substrate. In fructose, S. cerevisiae CAT-1 stood out with higher values for μmax (0.25 h-1), qS (2.24 h-1), and PEth (0.60 gEth L-1 h-1). Meyerozyma guilliermondii Recol 09 and C. parapsilosis Recol 37 had prolonged fermentation times and residual substrate. In sucrose, only S. cerevisiae CAT-1, S. cerevisiae BB9, and Pichia kudriavzevii Recol 39 consumed all the substrate, displaying higher PEth (0.72, 0.51, and 0.44 gEth L-1 h-1, respectively) compared to other carbon sources.
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Affiliation(s)
- Cinthia Aparecida de Andrade Silva
- Center for Studies in Natural Resources, State University of Mato Grosso do Sul, Dourados, MS, Brazil; Laboratory of Bioengineering, Faculty of Biological and Environmental Sciences, Federal University of Grande Dourados, Dourados, MS, Brazil
| | - Marta Ligia Oka
- Laboratory of Bioengineering, Faculty of Biological and Environmental Sciences, Federal University of Grande Dourados, Dourados, MS, Brazil
| | - Pedro Garcia Pereira da Silva
- Laboratory of Bioengineering, Faculty of Biological and Environmental Sciences, Federal University of Grande Dourados, Dourados, MS, Brazil
| | - Janaina Mayumi Honma
- Laboratory of Bioengineering, Faculty of Biological and Environmental Sciences, Federal University of Grande Dourados, Dourados, MS, Brazil
| | - Rodrigo Simões Ribeiro Leite
- Laboratory of Enzymology and Fermentation Processes, Faculty of Biological and Environmental Sciences, Federal University of Grande Dourados, Dourados, MS, Brazil
| | - Gustavo Graciano Fonseca
- Faculty of Natural Resource Sciences, School of Health, Business and Science, University of Akureyri, Akureyri, Iceland.
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Christensen KE, Duarte A, Ma Z, Edwards JL, Brem RB. Dissecting an ancient stress resistance trait syndrome in the compost yeast Kluyveromyces marxianus. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.12.21.572915. [PMID: 38187519 PMCID: PMC10769334 DOI: 10.1101/2023.12.21.572915] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/09/2024]
Abstract
In the search to understand how evolution builds new traits, ancient events are often the hardest to dissect. Species-unique traits pose a particular challenge for geneticists-cases in which a character arose long ago and, in the modern day, is conserved within a species, distinguishing it from reproductively isolated relatives. In this work, we have developed the budding yeast genus Kluyveromyces as a model for mechanistic dissection of trait variation across species boundaries. Phenotypic profiling revealed robust heat and chemical-stress tolerance phenotypes that distinguished the compost yeast K. marxianus from the rest of the clade. We used culture-based, transcriptomic, and genetic approaches to characterize the metabolic requirements of the K. marxianus trait syndrome. We then generated a population-genomic resource for K. marxianus and harnessed it in molecular-evolution analyses, which found hundreds of housekeeping genes with evidence for adaptive protein variation unique to this species. Our data support a model in which, in the distant past, K. marxianus underwent a vastly complex remodeling of its proteome to achieve stress resistance. Such a polygenic architecture, involving nucleotide-level allelic variation on a massive scale, is consistent with theoretical models of the mechanisms of long-term adaptation, and suggests principles of broad relevance for interspecies trait genetics.
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Affiliation(s)
- Kaylee E. Christensen
- Department of Plant and Microbial Biology, University of California, Berkeley, Berkeley, CA, 94720
| | - Abel Duarte
- Department of Plant and Microbial Biology, University of California, Berkeley, Berkeley, CA, 94720
| | - Zhenzhen Ma
- Department of Plant and Microbial Biology, University of California, Berkeley, Berkeley, CA, 94720
- Current address: Department of Biology, Stanford University, Stanford, CA, 94305
| | - Judith L. Edwards
- Department of Plant and Microbial Biology, University of California, Berkeley, Berkeley, CA, 94720
| | - Rachel B. Brem
- Department of Plant and Microbial Biology, University of California, Berkeley, Berkeley, CA, 94720
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3
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Qiu Y, Lei P, Wang R, Sun L, Luo Z, Li S, Xu H. Kluyveromyces as promising yeast cell factories for industrial bioproduction: From bio-functional design to applications. Biotechnol Adv 2023; 64:108125. [PMID: 36870581 DOI: 10.1016/j.biotechadv.2023.108125] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/08/2022] [Revised: 02/26/2023] [Accepted: 02/27/2023] [Indexed: 03/06/2023]
Abstract
As the two most widely used Kluyveromyces yeast, Kluyveromyces marxianus and K. lactis have gained increasing attention as microbial chassis in biocatalysts, biomanufacturing and the utilization of low-cost raw materials owing to their high suitability to these applications. However, due to slow progress in the development of molecular genetic manipulation tools and synthetic biology strategies, Kluyveromyces yeast cell factories as biological manufacturing platforms have not been fully developed. In this review, we provide a comprehensive overview of the attractive characteristics and applications of Kluyveromyces cell factories, with special emphasis on the development of molecular genetic manipulation tools and systems engineering strategies for synthetic biology. In addition, future avenues in the development of Kluyveromyces cell factories for the utilization of simple carbon compounds as substrates, the dynamic regulation of metabolic pathways, and for rapid directed evolution of robust strains are proposed. We expect that more synthetic systems, synthetic biology tools and metabolic engineering strategies will adapt to and optimize for Kluyveromyces cell factories to achieve green biofabrication of multiple products with higher efficiency.
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Affiliation(s)
- Yibin Qiu
- College of Food Science and Light Industry, Nanjing Tech University, Nanjing 211816, PR China; State Key Laboratory of Materials-Oriented Chemical Engineering, Nanjing Tech University, Nanjing 211816, PR China
| | - Peng Lei
- College of Food Science and Light Industry, Nanjing Tech University, Nanjing 211816, PR China; State Key Laboratory of Materials-Oriented Chemical Engineering, Nanjing Tech University, Nanjing 211816, PR China
| | - Rui Wang
- College of Food Science and Light Industry, Nanjing Tech University, Nanjing 211816, PR China; State Key Laboratory of Materials-Oriented Chemical Engineering, Nanjing Tech University, Nanjing 211816, PR China
| | - Liang Sun
- College of Food Science and Light Industry, Nanjing Tech University, Nanjing 211816, PR China; State Key Laboratory of Materials-Oriented Chemical Engineering, Nanjing Tech University, Nanjing 211816, PR China
| | - Zhengshan Luo
- College of Food Science and Light Industry, Nanjing Tech University, Nanjing 211816, PR China; State Key Laboratory of Materials-Oriented Chemical Engineering, Nanjing Tech University, Nanjing 211816, PR China
| | - Sha Li
- College of Food Science and Light Industry, Nanjing Tech University, Nanjing 211816, PR China; State Key Laboratory of Materials-Oriented Chemical Engineering, Nanjing Tech University, Nanjing 211816, PR China.
| | - Hong Xu
- College of Food Science and Light Industry, Nanjing Tech University, Nanjing 211816, PR China; State Key Laboratory of Materials-Oriented Chemical Engineering, Nanjing Tech University, Nanjing 211816, PR China.
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4
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Jin Z, Vighi A, Dong Y, Bureau JA, Ignea C. Engineering membrane architecture for biotechnological applications. Biotechnol Adv 2023; 64:108118. [PMID: 36773706 DOI: 10.1016/j.biotechadv.2023.108118] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2022] [Revised: 02/02/2023] [Accepted: 02/06/2023] [Indexed: 02/12/2023]
Abstract
Cellular membranes, predominantly described as a dynamic bilayer, are composed of different lipids, transmembrane proteins, and carbohydrates. Most research on biological membranes focuses on the identification, characterization, and mechanistic aspects of their different components. These studies provide a fundamental understanding of membrane structure, function, and dynamics, establishing a basis for the development of membrane engineering strategies. To date, approaches in this field concentrate on membrane adaptation to harsh conditions during industrial fermentation, which can be caused by temperature, osmotic, or organic solvent stress. With advances in the field of metabolic engineering and synthetic biology, recent breakthroughs include proof of concept microbial production of essential medicines, such as cannabinoids and vinblastine. However, long pathways, low yields, and host adaptation continue to pose challenges to the efficient scale up production of many important compounds. The lipid bilayer is profoundly linked to the activity of heterologous membrane-bound enzymes and transport of metabolites. Therefore, strategies for improving enzyme performance, facilitating pathway reconstruction, and enabling storage of products to increase the yields directly involve cellular membranes. At the forefront of membrane engineering research are re-emerging approaches in lipid research and synthetic biology that manipulate membrane size and composition and target lipid profiles across species. This review summarizes engineering strategies applied to cellular membranes and discusses the challenges and future perspectives, particularly with regards to their applications in host engineering and bioproduction.
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Affiliation(s)
- Zimo Jin
- Department of Bioengineering, McGill University, Montreal, Quebec H3A 0E9, Canada
| | - Asia Vighi
- Department of Bioengineering, McGill University, Montreal, Quebec H3A 0E9, Canada
| | - Yueming Dong
- Department of Bioengineering, McGill University, Montreal, Quebec H3A 0E9, Canada
| | | | - Codruta Ignea
- Department of Bioengineering, McGill University, Montreal, Quebec H3A 0E9, Canada.
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Xu X, Zhang W, You C, Fan C, Ji W, Park JT, Kwak J, Chen H, Zhang YHPJ, Ma Y. Biosynthesis of artificial starch and microbial protein from agricultural residue. Sci Bull (Beijing) 2023; 68:214-223. [PMID: 36641289 DOI: 10.1016/j.scib.2023.01.006] [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: 11/26/2022] [Revised: 12/30/2022] [Accepted: 01/04/2023] [Indexed: 01/09/2023]
Abstract
Growing populations and climate change pose great challenges to food security. Humankind is confronting a serious question: how will we feed the world in the near future? This study presents an out-of-the-box solution involving the highly efficient biosynthesis of artificial starch and microbial proteins from available and abundant agricultural residue as new feed and food sources. A one-pot biotransformation using an in vitro coenzyme-free synthetic enzymatic pathway and baker's yeast can simultaneously convert dilute sulfuric acid-pretreated corn stover to artificial starch and microbial protein under aerobic conditions. The β-glucosidase-free commercial cellulase mixture plus an ex vivo two-enzyme complex containing cellobiose phosphorylase and potato α-glucan phosphorylase displayed on the surface of Saccharomyces cerevisiae, showed better cellulose hydrolysis rates than a commercial β-glucosidase-rich cellulase mixture. This is because the channeling of the hydrolytic product from the solid cellulosic feedstock to the yeast mitigated the inhibition of the cellulase cocktail. Animal tests have shown that the digestion of artificial amylose results in slow and relatively small changes in blood sugar levels, suggesting that it could be a new health food component that prevents obesity and diabetes. A combination of the utilization of available agricultural residue and the biosynthesis of starch and microbial protein from non-food biomass could address the looming food crisis in the food-energy-water nexus.
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Affiliation(s)
- Xinxin Xu
- Biotechnology Research Institute, Chinese Academy of Agricultural Sciences, Beijing 100081, China
| | - Wei Zhang
- Biotechnology Research Institute, Chinese Academy of Agricultural Sciences, Beijing 100081, China.
| | - Chun You
- Key Laboratory of Engineering Biology for Low-Carbon Manufacturing, Tianjin Institute of Industrial Biotechnology, Chinese Academy of Sciences, Tianjin 300308, China
| | - Chao Fan
- Biotechnology Research Institute, Chinese Academy of Agricultural Sciences, Beijing 100081, China
| | - Wangli Ji
- Biotechnology Research Institute, Chinese Academy of Agricultural Sciences, Beijing 100081, China
| | - Jong-Tae Park
- Department of Food Science and Technology, Chungnam National University, Daejeon 34134, Republic of Korea
| | - Jiyun Kwak
- Department of Food Science and Technology, Chungnam National University, Daejeon 34134, Republic of Korea
| | - Hongge Chen
- College of Life Sciences, Henan Agricultural University, Zhengzhou 450002, China
| | - Yi-Heng P Job Zhang
- Key Laboratory of Engineering Biology for Low-Carbon Manufacturing, Tianjin Institute of Industrial Biotechnology, Chinese Academy of Sciences, Tianjin 300308, China.
| | - Yanhe Ma
- Key Laboratory of Engineering Biology for Low-Carbon Manufacturing, Tianjin Institute of Industrial Biotechnology, Chinese Academy of Sciences, Tianjin 300308, China.
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Mbuyane LL, Bauer FF, Bloem A, Camarasa C, Ortiz-Julien A, Divol B. Species-Dependent Metabolic Response to Lipid Mixtures in Wine Yeasts. Front Microbiol 2022; 13:823581. [PMID: 35677913 PMCID: PMC9168537 DOI: 10.3389/fmicb.2022.823581] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/27/2021] [Accepted: 04/14/2022] [Indexed: 11/13/2022] Open
Abstract
Lipids are essential energy storage compounds and are the core structural elements of all biological membranes. During wine alcoholic fermentation, the ability of yeasts to adjust the lipid composition of the plasma membrane partly determines their ability to cope with various fermentation-related stresses, including elevated levels of ethanol and the presence of weak acids. In addition, the lipid composition of grape juice also impacts the production of many wine-relevant aromatic compounds. Several studies have evaluated the impact of lipids and of their metabolism on fermentation performance and aroma production in the dominant wine yeast Saccharomyces cerevisiae, but limited information is available on other yeast species. Thus, the aim of this study was to evaluate the influence of specific fatty acid and sterol mixtures on various non-Saccharomyces yeast fermentation rates and the production of primary fermentation metabolites. The data show that the response to different lipid mixtures is species-dependent. For Metschnikowia pulcherrima, a slight increase in carbon dioxide production was observed in media enriched with unsaturated fatty acids whereas Kluyveromyces marxianus fermented significantly better in synthetic media containing a higher concentration of polyunsaturated fatty acids than monounsaturated fatty acids. Torulaspora delbrueckii fermentation rate increased in media supplemented with lipids present at an equimolar concentration. The data indicate that these different responses may be linked to variations in the lipid profile of these yeasts and divergent metabolic activities, in particular the regulation of acetyl-CoA metabolism. Finally, the results suggest that the yeast metabolic footprint and ultimately the wine organoleptic properties could be optimized via species-specific lipid adjustments.
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Affiliation(s)
- Lethiwe L Mbuyane
- Department of Viticulture and Oenology, South African Grape and Wine Research Institute, Stellenbosch University, Stellenbosch, South Africa
| | - Florian F Bauer
- Department of Viticulture and Oenology, South African Grape and Wine Research Institute, Stellenbosch University, Stellenbosch, South Africa
| | - Audrey Bloem
- UMR SPO, INRA, SupAgroM, Université de Montpellier, Montpellier, France
| | - Carole Camarasa
- UMR SPO, INRA, SupAgroM, Université de Montpellier, Montpellier, France
| | | | - Benoit Divol
- Department of Viticulture and Oenology, South African Grape and Wine Research Institute, Stellenbosch University, Stellenbosch, South Africa
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7
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van Aalst AC, de Valk SC, van Gulik WM, Jansen ML, Pronk JT, Mans R. Pathway engineering strategies for improved product yield in yeast-based industrial ethanol production. Synth Syst Biotechnol 2022; 7:554-566. [PMID: 35128088 PMCID: PMC8792080 DOI: 10.1016/j.synbio.2021.12.010] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/29/2021] [Revised: 12/22/2021] [Accepted: 12/23/2021] [Indexed: 12/16/2022] Open
Abstract
Product yield on carbohydrate feedstocks is a key performance indicator for industrial ethanol production with the yeast Saccharomyces cerevisiae. This paper reviews pathway engineering strategies for improving ethanol yield on glucose and/or sucrose in anaerobic cultures of this yeast by altering the ratio of ethanol production, yeast growth and glycerol formation. Particular attention is paid to strategies aimed at altering energy coupling of alcoholic fermentation and to strategies for altering redox-cofactor coupling in carbon and nitrogen metabolism that aim to reduce or eliminate the role of glycerol formation in anaerobic redox metabolism. In addition to providing an overview of scientific advances we discuss context dependency, theoretical impact and potential for industrial application of different proposed and developed strategies.
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Affiliation(s)
- Aafke C.A. van Aalst
- Department of Biotechnology, Delft University of Technology, Van der Maasweg 9, 2629, HZ Delft, the Netherlands
| | - Sophie C. de Valk
- Department of Biotechnology, Delft University of Technology, Van der Maasweg 9, 2629, HZ Delft, the Netherlands
| | - Walter M. van Gulik
- Department of Biotechnology, Delft University of Technology, Van der Maasweg 9, 2629, HZ Delft, the Netherlands
| | - Mickel L.A. Jansen
- DSM Biotechnology Centre, Alexander Fleminglaan 1, 2613, AX Delft, the Netherlands
| | - Jack T. Pronk
- Department of Biotechnology, Delft University of Technology, Van der Maasweg 9, 2629, HZ Delft, the Netherlands
| | - Robert Mans
- Department of Biotechnology, Delft University of Technology, Van der Maasweg 9, 2629, HZ Delft, the Netherlands
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8
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Dekker WJC, Jürgens H, Ortiz-Merino RA, Mooiman C, van den Berg R, Kaljouw A, Mans R, Pronk JT. OUP accepted manuscript. FEMS Yeast Res 2022; 22:6523363. [PMID: 35137036 PMCID: PMC8862043 DOI: 10.1093/femsyr/foac007] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/10/2021] [Revised: 01/26/2022] [Accepted: 02/03/2022] [Indexed: 11/13/2022] Open
Abstract
While thermotolerance is an attractive trait for yeasts used in industrial ethanol production, oxygen requirements of known thermotolerant species are incompatible with process requirements. Analysis of oxygen-sufficient and oxygen-limited chemostat cultures of the facultatively fermentative, thermotolerant species Ogataea parapolymorpha showed its minimum oxygen requirements to be an order of magnitude larger than those reported for the thermotolerant yeast Kluyveromyces marxianus. High oxygen requirements of O. parapolymorpha coincided with a near absence of glycerol, a key NADH/NAD+ redox-cofactor-balancing product in many other yeasts, in oxygen-limited cultures. Genome analysis indicated absence of orthologs of the Saccharomyces cerevisiae glycerol-3-phosphate-phosphatase genes GPP1 and GPP2. Co-feeding of acetoin, whose conversion to 2,3-butanediol enables reoxidation of cytosolic NADH, supported a 2.5-fold increase of the biomass concentration in oxygen-limited cultures. An O. parapolymorpha strain in which key genes involved in mitochondrial reoxidation of NADH were inactivated did produce glycerol, but transcriptome analysis did not reveal a clear candidate for a responsible phosphatase. Expression of S. cerevisiae GPD2, which encodes NAD+-dependent glycerol-3-phosphate dehydrogenase, and GPP1 supported increased glycerol production by oxygen-limited chemostat cultures of O. parapolymorpha. These results identify dependence on respiration for NADH reoxidation as a key contributor to unexpectedly high oxygen requirements of O. parapolymorpha.
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Affiliation(s)
- Wijbrand J C Dekker
- Department of Biotechnology, Delft University of Technology, van der Maasweg 9, 2629 HZ Delft, The Netherlands
| | - Hannes Jürgens
- Department of Biotechnology, Delft University of Technology, van der Maasweg 9, 2629 HZ Delft, The Netherlands
| | - Raúl A Ortiz-Merino
- Department of Biotechnology, Delft University of Technology, van der Maasweg 9, 2629 HZ Delft, The Netherlands
| | - Christiaan Mooiman
- Department of Biotechnology, Delft University of Technology, van der Maasweg 9, 2629 HZ Delft, The Netherlands
| | - Remon van den Berg
- Department of Biotechnology, Delft University of Technology, van der Maasweg 9, 2629 HZ Delft, The Netherlands
| | - Astrid Kaljouw
- Department of Biotechnology, Delft University of Technology, van der Maasweg 9, 2629 HZ Delft, The Netherlands
| | - Robert Mans
- Department of Biotechnology, Delft University of Technology, van der Maasweg 9, 2629 HZ Delft, The Netherlands
| | - Jack T Pronk
- Corresponding author: Department of Biotechnology, Delft University of Technology, van der Maasweg 9, 2629 HZ Delft, The Netherlands. Tel: +31 15 2783214; E-mail:
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9
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Bouwknegt J, Koster CC, Vos AM, Ortiz-Merino RA, Wassink M, Luttik MAH, van den Broek M, Hagedoorn PL, Pronk JT. Class-II dihydroorotate dehydrogenases from three phylogenetically distant fungi support anaerobic pyrimidine biosynthesis. Fungal Biol Biotechnol 2021; 8:10. [PMID: 34656184 PMCID: PMC8520639 DOI: 10.1186/s40694-021-00117-4] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/29/2021] [Accepted: 10/02/2021] [Indexed: 11/10/2022] Open
Abstract
Background In most fungi, quinone-dependent Class-II dihydroorotate dehydrogenases (DHODs) are essential for pyrimidine biosynthesis. Coupling of these Class-II DHODHs to mitochondrial respiration makes their in vivo activity dependent on oxygen availability. Saccharomyces cerevisiae and closely related yeast species harbor a cytosolic Class-I DHOD (Ura1) that uses fumarate as electron acceptor and thereby enables anaerobic pyrimidine synthesis. Here, we investigate DHODs from three fungi (the Neocallimastigomycete Anaeromyces robustus and the yeasts Schizosaccharomyces japonicus and Dekkera bruxellensis) that can grow anaerobically but, based on genome analysis, only harbor a Class-II DHOD. Results Heterologous expression of putative Class-II DHOD-encoding genes from fungi capable of anaerobic, pyrimidine-prototrophic growth (Arura9, SjURA9, DbURA9) in an S. cerevisiae ura1Δ strain supported aerobic as well as anaerobic pyrimidine prototrophy. A strain expressing DbURA9 showed delayed anaerobic growth without pyrimidine supplementation. Adapted faster growing DbURA9-expressing strains showed mutations in FUM1, which encodes fumarase. GFP-tagged SjUra9 and DbUra9 were localized to S. cerevisiae mitochondria, while ArUra9, whose sequence lacked a mitochondrial targeting sequence, was localized to the yeast cytosol. Experiments with cell extracts showed that ArUra9 used free FAD and FMN as electron acceptors. Expression of SjURA9 in S. cerevisiae reproducibly led to loss of respiratory competence and mitochondrial DNA. A cysteine residue (C265 in SjUra9) in the active sites of all three anaerobically active Ura9 orthologs was shown to be essential for anaerobic activity of SjUra9 but not of ArUra9. Conclusions Activity of fungal Class-II DHODs was long thought to be dependent on an active respiratory chain, which in most fungi requires the presence of oxygen. By heterologous expression experiments in S. cerevisiae, this study shows that phylogenetically distant fungi independently evolved Class-II dihydroorotate dehydrogenases that enable anaerobic pyrimidine biosynthesis. Further structure–function studies are required to understand the mechanistic basis for the anaerobic activity of Class-II DHODs and an observed loss of respiratory competence in S. cerevisiae strains expressing an anaerobically active DHOD from Sch. japonicus. Supplementary Information The online version contains supplementary material available at 10.1186/s40694-021-00117-4.
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Affiliation(s)
- Jonna Bouwknegt
- Department of Biotechnology, Delft University of Technology, van der Maasweg 9, 2629 HZ, Delft, The Netherlands
| | - Charlotte C Koster
- Department of Biotechnology, Delft University of Technology, van der Maasweg 9, 2629 HZ, Delft, The Netherlands
| | - Aurin M Vos
- Wageningen Plant Research, Wageningen University and Research, Droevendaalsesteeg 1, 6708 PB, Wageningen, The Netherlands
| | - Raúl A Ortiz-Merino
- Department of Biotechnology, Delft University of Technology, van der Maasweg 9, 2629 HZ, Delft, The Netherlands
| | - Mats Wassink
- Department of Biotechnology, Delft University of Technology, van der Maasweg 9, 2629 HZ, Delft, The Netherlands
| | - Marijke A H Luttik
- Department of Biotechnology, Delft University of Technology, van der Maasweg 9, 2629 HZ, Delft, The Netherlands
| | - Marcel van den Broek
- Department of Biotechnology, Delft University of Technology, van der Maasweg 9, 2629 HZ, Delft, The Netherlands
| | - Peter L Hagedoorn
- Department of Biotechnology, Delft University of Technology, van der Maasweg 9, 2629 HZ, Delft, The Netherlands
| | - Jack T Pronk
- Department of Biotechnology, Delft University of Technology, van der Maasweg 9, 2629 HZ, Delft, The Netherlands.
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