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Chen Y, Zhang Y, Siewers V, Nielsen J. Ach1 is involved in shuttling mitochondrial acetyl units for cytosolic C2 provision in Saccharomyces cerevisiae lacking pyruvate decarboxylase. FEMS Yeast Res 2015; 15:fov015. [PMID: 25852051 DOI: 10.1093/femsyr/fov015] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 03/23/2015] [Indexed: 11/14/2022] Open
Abstract
Acetyl-coenzyme A (acetyl-CoA) is not only an essential intermediate in central carbon metabolism, but also an important precursor metabolite for native or engineered pathways that can produce many products of commercial interest such as pharmaceuticals, chemicals or biofuels. In the yeast Saccharomyces cerevisiae, acetyl-CoA is compartmentalized in the cytosol, mitochondrion, peroxisome and nucleus, and cannot be directly transported between these compartments. With the acetyl-carnitine or glyoxylate shuttle, acetyl-CoA produced in peroxisomes or the cytoplasm can be transported into the cytoplasm or the mitochondria. However, whether acetyl-CoA generated in the mitochondria can be exported to the cytoplasm is still unclear. Here, we investigated whether the transfer of acetyl-CoA from the mitochondria to the cytoplasm can occur using a pyruvate decarboxylase negative, non-fermentative yeast strain. We found that mitochondrial Ach1 can convert acetyl-CoA in this compartment into acetate, which crosses the mitochondrial membrane before being converted into acetyl-CoA in the cytosol. Based on our finding we propose a model in which acetate can be used to exchange acetyl units between mitochondria and the cytosol. These results will increase our fundamental understanding of intracellular transport of acetyl units, and also help to develop microbial cell factories for many kinds of acetyl-CoA derived products.
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Affiliation(s)
- Yun Chen
- Department of Biology & Biological Engineering, Chalmers University of Technology, SE-412 96 Gothenburg, Sweden
| | - Yiming Zhang
- Department of Biology & Biological Engineering, Chalmers University of Technology, SE-412 96 Gothenburg, Sweden
| | - Verena Siewers
- Department of Biology & Biological Engineering, Chalmers University of Technology, SE-412 96 Gothenburg, Sweden
| | - Jens Nielsen
- Department of Biology & Biological Engineering, Chalmers University of Technology, SE-412 96 Gothenburg, Sweden; Novo Nordisk Foundation Center for Biosustainability, Technical University of Denmark, DK-2970 Hørsholm, Denmark
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Krivoruchko A, Zhang Y, Siewers V, Chen Y, Nielsen J. Microbial acetyl-CoA metabolism and metabolic engineering. Metab Eng 2014; 28:28-42. [PMID: 25485951 DOI: 10.1016/j.ymben.2014.11.009] [Citation(s) in RCA: 195] [Impact Index Per Article: 19.5] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/16/2014] [Revised: 11/25/2014] [Accepted: 11/26/2014] [Indexed: 12/23/2022]
Abstract
Recent concerns over the sustainability of petrochemical-based processes for production of desired chemicals have fueled research into alternative modes of production. Metabolic engineering of microbial cell factories such as Saccharomyces cerevisiae and Escherichia coli offers a sustainable and flexible alternative for the production of various molecules. Acetyl-CoA is a key molecule in microbial central carbon metabolism and is involved in a variety of cellular processes. In addition, it functions as a precursor for many molecules of biotechnological relevance. Therefore, much interest exists in engineering the metabolism around the acetyl-CoA pools in cells in order to increase product titers. Here we provide an overview of the acetyl-CoA metabolism in eukaryotic and prokaryotic microbes (with a focus on S. cerevisiae and E. coli), with an emphasis on reactions involved in the production and consumption of acetyl-CoA. In addition, we review various strategies that have been used to increase acetyl-CoA production in these microbes.
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Affiliation(s)
- Anastasia Krivoruchko
- Department of Chemical and Biological Engineering, Chalmers University of Technology, Gothenburg, Sweden
| | - Yiming Zhang
- Department of Chemical and Biological Engineering, Chalmers University of Technology, Gothenburg, Sweden
| | - Verena Siewers
- Department of Chemical and Biological Engineering, Chalmers University of Technology, Gothenburg, Sweden
| | - Yun Chen
- Department of Chemical and Biological Engineering, Chalmers University of Technology, Gothenburg, Sweden
| | - Jens Nielsen
- Department of Chemical and Biological Engineering, Chalmers University of Technology, Gothenburg, Sweden.
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Abstract
The yeast Saccharomyces cerevisiae is a widely used cell factory for the production of fuels, chemicals, and pharmaceuticals. The use of this cell factory for cost-efficient production of novel fuels and chemicals requires high yields and low by-product production. Many industrially interesting chemicals are biosynthesized from acetyl coenzyme A (acetyl-CoA), which serves as a central precursor metabolite in yeast. To ensure high yields in production of these chemicals, it is necessary to engineer the central carbon metabolism so that ethanol production is minimized (or eliminated) and acetyl-CoA can be formed from glucose in high yield. Here the perspective of generating yeast platform strains that have such properties is discussed in the context of a major breakthrough with expression of a functional pyruvate dehydrogenase complex in the cytosol.
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Engineering acetyl coenzyme A supply: functional expression of a bacterial pyruvate dehydrogenase complex in the cytosol of Saccharomyces cerevisiae. mBio 2014; 5:e01696-14. [PMID: 25336454 PMCID: PMC4212835 DOI: 10.1128/mbio.01696-14] [Citation(s) in RCA: 70] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
The energetic (ATP) cost of biochemical pathways critically determines the maximum yield of metabolites of vital or commercial relevance. Cytosolic acetyl coenzyme A (acetyl-CoA) is a key precursor for biosynthesis in eukaryotes and for many industrially relevant product pathways that have been introduced into Saccharomyces cerevisiae, such as isoprenoids or lipids. In this yeast, synthesis of cytosolic acetyl-CoA via acetyl-CoA synthetase (ACS) involves hydrolysis of ATP to AMP and pyrophosphate. Here, we demonstrate that expression and assembly in the yeast cytosol of an ATP-independent pyruvate dehydrogenase complex (PDH) from Enterococcus faecalis can fully replace the ACS-dependent pathway for cytosolic acetyl-CoA synthesis. In vivo activity of E. faecalis PDH required simultaneous expression of E. faecalis genes encoding its E1α, E1β, E2, and E3 subunits, as well as genes involved in lipoylation of E2, and addition of lipoate to growth media. A strain lacking ACS that expressed these E. faecalis genes grew at near-wild-type rates on glucose synthetic medium supplemented with lipoate, under aerobic and anaerobic conditions. A physiological comparison of the engineered strain and an isogenic Acs(+) reference strain showed small differences in biomass yields and metabolic fluxes. Cellular fractionation and gel filtration studies revealed that the E. faecalis PDH subunits were assembled in the yeast cytosol, with a subunit ratio and enzyme activity similar to values reported for PDH purified from E. faecalis. This study indicates that cytosolic expression and assembly of PDH in eukaryotic industrial microorganisms is a promising option for minimizing the energy costs of precursor supply in acetyl-CoA-dependent product pathways. Importance: Genetically engineered microorganisms are intensively investigated and applied for production of biofuels and chemicals from renewable sugars. To make such processes economically and environmentally sustainable, the energy (ATP) costs for product formation from sugar must be minimized. Here, we focus on an important ATP-requiring process in baker's yeast (Saccharomyces cerevisiae): synthesis of cytosolic acetyl coenzyme A, a key precursor for many industrially important products, ranging from biofuels to fragrances. We demonstrate that pyruvate dehydrogenase from the bacterium Enterococcus faecalis, a huge enzyme complex with a size similar to that of a ribosome, can be functionally expressed and assembled in the cytosol of baker's yeast. Moreover, we show that this ATP-independent mechanism for cytosolic acetyl-CoA synthesis can entirely replace the ATP-costly native yeast pathway. This work provides metabolic engineers with a new option to optimize the performance of baker's yeast as a "cell factory" for sustainable production of fuels and chemicals.
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Kildegaard KR, Hallström BM, Blicher TH, Sonnenschein N, Jensen NB, Sherstyk S, Harrison SJ, Maury J, Herrgård MJ, Juncker AS, Forster J, Nielsen J, Borodina I. Evolution reveals a glutathione-dependent mechanism of 3-hydroxypropionic acid tolerance. Metab Eng 2014; 26:57-66. [PMID: 25263954 DOI: 10.1016/j.ymben.2014.09.004] [Citation(s) in RCA: 62] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/05/2014] [Revised: 08/15/2014] [Accepted: 09/15/2014] [Indexed: 12/19/2022]
Abstract
Biologically produced 3-hydroxypropionic acid (3 HP) is a potential source for sustainable acrylates and can also find direct use as monomer in the production of biodegradable polymers. For industrial-scale production there is a need for robust cell factories tolerant to high concentration of 3 HP, preferably at low pH. Through adaptive laboratory evolution we selected S. cerevisiae strains with improved tolerance to 3 HP at pH 3.5. Genome sequencing followed by functional analysis identified the causal mutation in SFA1 gene encoding S-(hydroxymethyl)glutathione dehydrogenase. Based on our findings, we propose that 3 HP toxicity is mediated by 3-hydroxypropionic aldehyde (reuterin) and that glutathione-dependent reactions are used for reuterin detoxification. The identified molecular response to 3 HP and reuterin may well be a general mechanism for handling resistance to organic acid and aldehydes by living cells.
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Affiliation(s)
- Kanchana R Kildegaard
- The Novo Nordisk Foundation Center for Biosustainability, Technical University of Denmark, Kogle Allé 6, DK-2970 Hørsholm, Denmark
| | - Björn M Hallström
- Science for Life Laboratory, KTH Royal Institution of Technology, Box 1031, SE-171 21 Solna, Sweden
| | - Thomas H Blicher
- The Novo Nordisk Foundation Center for Protein Research, University of Copenhagen, Blegdamsvej 3b, DK-2200 Copenhagen , Denmark
| | - Nikolaus Sonnenschein
- The Novo Nordisk Foundation Center for Biosustainability, Technical University of Denmark, Kogle Allé 6, DK-2970 Hørsholm, Denmark
| | - Niels B Jensen
- The Novo Nordisk Foundation Center for Biosustainability, Technical University of Denmark, Kogle Allé 6, DK-2970 Hørsholm, Denmark
| | - Svetlana Sherstyk
- The Novo Nordisk Foundation Center for Biosustainability, Technical University of Denmark, Kogle Allé 6, DK-2970 Hørsholm, Denmark
| | - Scott J Harrison
- The Novo Nordisk Foundation Center for Biosustainability, Technical University of Denmark, Kogle Allé 6, DK-2970 Hørsholm, Denmark
| | - Jérôme Maury
- The Novo Nordisk Foundation Center for Biosustainability, Technical University of Denmark, Kogle Allé 6, DK-2970 Hørsholm, Denmark
| | - Markus J Herrgård
- The Novo Nordisk Foundation Center for Biosustainability, Technical University of Denmark, Kogle Allé 6, DK-2970 Hørsholm, Denmark
| | - Agnieszka S Juncker
- The Novo Nordisk Foundation Center for Biosustainability, Technical University of Denmark, Kogle Allé 6, DK-2970 Hørsholm, Denmark
| | - Jochen Forster
- The Novo Nordisk Foundation Center for Biosustainability, Technical University of Denmark, Kogle Allé 6, DK-2970 Hørsholm, Denmark
| | - Jens Nielsen
- The Novo Nordisk Foundation Center for Biosustainability, Technical University of Denmark, Kogle Allé 6, DK-2970 Hørsholm, Denmark; Department of Chemical and Biological Engineering, Chalmers University of Technology, Kemivägen 10, SE-412 96 Göteborg, Sweden
| | - Irina Borodina
- The Novo Nordisk Foundation Center for Biosustainability, Technical University of Denmark, Kogle Allé 6, DK-2970 Hørsholm, Denmark.
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Lian J, Si T, Nair NU, Zhao H. Design and construction of acetyl-CoA overproducing Saccharomyces cerevisiae strains. Metab Eng 2014; 24:139-49. [PMID: 24853351 DOI: 10.1016/j.ymben.2014.05.010] [Citation(s) in RCA: 160] [Impact Index Per Article: 16.0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2013] [Revised: 04/04/2014] [Accepted: 05/12/2014] [Indexed: 11/28/2022]
Abstract
Saccharomyces cerevisiae has increasingly been engineered as a cell factory for efficient and economic production of fuels and chemicals from renewable resources. Notably, a wide variety of industrially important products are derived from the same precursor metabolite, acetyl-CoA. However, the limited supply of acetyl-CoA in the cytosol, where biosynthesis generally happens, often leads to low titer and yield of the desired products in yeast. In the present work, combined strategies of disrupting competing pathways and introducing heterologous biosynthetic pathways were carried out to increase acetyl-CoA levels by using the CoA-dependent n-butanol production as a reporter. By inactivating ADH1 and ADH4 for ethanol formation and GPD1 and GPD2 for glycerol production, the glycolytic flux was redirected towards acetyl-CoA, resulting in 4-fold improvement in n-butanol production. Subsequent introduction of heterologous acetyl-CoA biosynthetic pathways, including pyruvate dehydrogenase (PDH), ATP-dependent citrate lyase (ACL), and PDH-bypass, further increased n-butanol production. Recombinant PDHs localized in the cytosol (cytoPDHs) were found to be the most efficient, which increased n-butanol production by additional 3 fold. In total, n-butanol titer and acetyl-CoA concentration were increased more than 12 fold and 3 fold, respectively. By combining the most effective and complementary acetyl-CoA pathways, more than 100mg/L n-butanol could be produced using high cell density fermentation, which represents the highest titer ever reported in yeast using the clostridial CoA-dependent pathway.
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Affiliation(s)
- Jiazhang Lian
- Department of Chemical and Biomolecular Engineering, University of Illinois at Urbana-Champaign, Urbana, IL 61801, United States; Energy Biosciences Institute, Institute for Genomic Biology, University of Illinois at Urbana-Champaign, Urbana, IL 61801, United States
| | - Tong Si
- Department of Chemical and Biomolecular Engineering, University of Illinois at Urbana-Champaign, Urbana, IL 61801, United States
| | - Nikhil U Nair
- Department of Chemical and Biomolecular Engineering, University of Illinois at Urbana-Champaign, Urbana, IL 61801, United States; Department of Chemical and Biological Engineering, Tufts University, Medford, MA 02155, United States
| | - Huimin Zhao
- Department of Chemical and Biomolecular Engineering, University of Illinois at Urbana-Champaign, Urbana, IL 61801, United States; Energy Biosciences Institute, Institute for Genomic Biology, University of Illinois at Urbana-Champaign, Urbana, IL 61801, United States; Departments of Chemistry, Biochemistry, and Bioengineering, University of Illinois at Urbana-Champaign, Urbana, IL 61801, United States.
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57
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Borodina I, Nielsen J. Advances in metabolic engineering of yeast Saccharomyces cerevisiae for production of chemicals. Biotechnol J 2014; 9:609-20. [PMID: 24677744 DOI: 10.1002/biot.201300445] [Citation(s) in RCA: 179] [Impact Index Per Article: 17.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/11/2013] [Revised: 12/05/2013] [Accepted: 01/24/2014] [Indexed: 11/12/2022]
Abstract
Yeast Saccharomyces cerevisiae is an important industrial host for production of enzymes, pharmaceutical and nutraceutical ingredients and recently also commodity chemicals and biofuels. Here, we review the advances in modeling and synthetic biology tools and how these tools can speed up the development of yeast cell factories. We also present an overview of metabolic engineering strategies for developing yeast strains for production of polymer monomers: lactic, succinic, and cis,cis-muconic acids. S. cerevisiae has already firmly established itself as a cell factory in industrial biotechnology and the advances in yeast strain engineering will stimulate development of novel yeast-based processes for chemicals production.
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Affiliation(s)
- Irina Borodina
- The Novo Nordisk Foundation Center for Biosustainability, Technical University of Denmark, Hørsholm, Denmark
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58
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Lian J, Chao R, Zhao H. Metabolic engineering of a Saccharomyces cerevisiae strain capable of simultaneously utilizing glucose and galactose to produce enantiopure (2R,3R)-butanediol. Metab Eng 2014; 23:92-9. [PMID: 24525332 DOI: 10.1016/j.ymben.2014.02.003] [Citation(s) in RCA: 80] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/25/2013] [Revised: 01/21/2014] [Accepted: 02/03/2014] [Indexed: 11/18/2022]
Abstract
2,3-Butanediol (BDO) is an important chemical with broad industrial applications and can be naturally produced by many bacteria at high levels. However, the pathogenicity of these native producers is a major obstacle for large scale production. Here we report the engineering of an industrially friendly host, Saccharomyces cerevisiae, to produce BDO at high titer and yield. By inactivation of pyruvate decarboxylases (PDCs) followed by overexpression of MTH1 and adaptive evolution, the resultant yeast grew on glucose as the sole carbon source with ethanol production completely eliminated. Moreover, the pdc- strain consumed glucose and galactose simultaneously, which to our knowledge is unprecedented in S. cerevisiae strains. Subsequent introduction of a BDO biosynthetic pathway consisting of the cytosolic acetolactate synthase (cytoILV2), Bacillus subtilis acetolactate decarboxylase (BsAlsD), and the endogenous butanediol dehydrogenase (BDH1) resulted in the production of enantiopure (2R,3R)-butanediol (R-BDO). In shake flask fermentation, a yield over 70% of the theoretical value was achieved. Using fed-batch fermentation, more than 100g/L R-BDO (1100mM) was synthesized from a mixture of glucose and galactose, two major carbohydrate components in red algae. The high titer and yield of the enantiopure R-BDO produced as well as the ability to co-ferment glucose and galactose make our engineered yeast strain a superior host for cost-effective production of bio-based BDO from renewable resources.
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Affiliation(s)
- Jiazhang Lian
- Department of Chemical and Biomolecular Engineering, University of Illinois at Urbana-Champaign, Urbana, IL 61801, United States; Energy Biosciences Institute, Institute for Genomic Biology, University of Illinois at Urbana-Champaign, Urbana, IL 61801, United States
| | - Ran Chao
- Department of Chemical and Biomolecular Engineering, University of Illinois at Urbana-Champaign, Urbana, IL 61801, United States; Energy Biosciences Institute, Institute for Genomic Biology, University of Illinois at Urbana-Champaign, Urbana, IL 61801, United States
| | - Huimin Zhao
- Department of Chemical and Biomolecular Engineering, University of Illinois at Urbana-Champaign, Urbana, IL 61801, United States; Energy Biosciences Institute, Institute for Genomic Biology, University of Illinois at Urbana-Champaign, Urbana, IL 61801, United States; Departments of Chemistry, Biochemistry, and Bioengineering, University of Illinois at Urbana-Champaign, Urbana, IL 61801, United States.
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59
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Matsuda F, Ishii J, Kondo T, Ida K, Tezuka H, Kondo A. Increased isobutanol production in Saccharomyces cerevisiae by eliminating competing pathways and resolving cofactor imbalance. Microb Cell Fact 2013; 12:119. [PMID: 24305546 PMCID: PMC3866936 DOI: 10.1186/1475-2859-12-119] [Citation(s) in RCA: 95] [Impact Index Per Article: 8.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/08/2013] [Accepted: 11/05/2013] [Indexed: 11/10/2022] Open
Abstract
Background Isobutanol is an important target for biorefinery research as a next-generation biofuel and a building block for commodity chemical production. Metabolically engineered microbial strains to produce isobutanol have been successfully developed by introducing the Ehrlich pathway into bacterial hosts. Isobutanol-producing baker’s yeast (Saccharomyces cerevisiae) strains have been developed following the strategy with respect to its advantageous characteristics for cost-effective isobutanol production. However, the isobutanol yields and titers attained by the developed strains need to be further improved through engineering of S. cerevisiae metabolism. Results Two strategies including eliminating competing pathways and resolving the cofactor imbalance were applied to improve isobutanol production in S. cerevisiae. Isobutanol production levels were increased in strains lacking genes encoding members of the pyruvate dehydrogenase complex such as LPD1, indicating that the pyruvate supply for isobutanol biosynthesis is competing with acetyl-CoA biosynthesis in mitochondria. Isobutanol production was increased by overexpression of enzymes responsible for transhydrogenase-like shunts such as pyruvate carboxylase, malate dehydrogenase, and malic enzyme. The integration of a single gene deletion lpd1Δ and the activation of the transhydrogenase-like shunt further increased isobutanol levels. In a batch fermentation test at the 50-mL scale from 100 g/L glucose using the two integrated strains, the isobutanol titer reached 1.62 ± 0.11 g/L and 1.61 ± 0.03 g/L at 24 h after the start of fermentation, which corresponds to the yield at 0.016 ± 0.001 g/g glucose consumed and 0.016 ± 0.0003 g/g glucose consumed, respectively. Conclusions These results demonstrate that downregulation of competing pathways and metabolic functions for resolving the cofactor imbalance are promising strategies to construct S. cerevisiae strains that effectively produce isobutanol.
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Affiliation(s)
| | | | | | | | | | - Akihiko Kondo
- RIKEN Center for Sustainable Resource Science, 1-7-22 Suehirocho, Turumi-ku, Yokohama, Kanagawa 230-0045, Japan.
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60
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Kim SJ, Seo SO, Jin YS, Seo JH. Production of 2,3-butanediol by engineered Saccharomyces cerevisiae. BIORESOURCE TECHNOLOGY 2013; 146:274-281. [PMID: 23941711 DOI: 10.1016/j.biortech.2013.07.081] [Citation(s) in RCA: 71] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/20/2013] [Revised: 07/16/2013] [Accepted: 07/18/2013] [Indexed: 05/04/2023]
Abstract
In order to produce 2,3-butanediol (2,3-BD) with a high titer, it is necessary to engineer Saccharomyces cerevisiae by deleting the competing pathway and overexpressing the 2,3-BD biosynthetic pathway. A pyruvate decarboxylase (Pdc)-deficient mutant was constructed and evolved for rapid glucose consumption without ethanol production. Genome re-sequencing of the evolved strain (SOS4) revealed a point mutation (A81P) in MTH1 coding for a transcriptional regulator involved in glucose sensing, unlike the previously reported Pdc-deficient mutant which had internal deletion in MTH1. When alsS and alsD genes from Bacillus subtilis, and endogenous BDH1 gene were overexpressed in SOS4, the resulting strain (BD4) not only produced 2,3-BD efficiently, but also consumed glucose faster than the parental strain. In fed-batch fermentation with optimum aeration, 2,3-BD concentration increased up to 96.2 g/L. These results suggest that S. cerevisiae might be a promising host for producing 2,3-BD for industrial applications.
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Affiliation(s)
- Soo-Jung Kim
- Department of Agricultural Biotechnology, Seoul National University, Seoul 151-921, South Korea; Center for Food and Bioconvergence, Seoul National University, Seoul 151-921, South Korea
| | - Seung-Oh Seo
- Department of Food Science and Human Nutrition, University of Illinois at Urbana-Champaign, Urbana, IL 61801, USA; Institute for Genomic Biology, 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; Institute for Genomic Biology, University of Illinois at Urbana-Champaign, Urbana, IL 61801, USA.
| | - Jin-Ho Seo
- Department of Agricultural Biotechnology, Seoul National University, Seoul 151-921, South Korea; Center for Food and Bioconvergence, Seoul National University, Seoul 151-921, South Korea.
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61
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Dragosits M, Mattanovich D. Adaptive laboratory evolution -- principles and applications for biotechnology. Microb Cell Fact 2013; 12:64. [PMID: 23815749 PMCID: PMC3716822 DOI: 10.1186/1475-2859-12-64] [Citation(s) in RCA: 425] [Impact Index Per Article: 38.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/22/2013] [Accepted: 06/24/2013] [Indexed: 11/19/2022] Open
Abstract
Adaptive laboratory evolution is a frequent method in biological studies to gain insights into the basic mechanisms of molecular evolution and adaptive changes that accumulate in microbial populations during long term selection under specified growth conditions. Although regularly performed for more than 25 years, the advent of transcript and cheap next-generation sequencing technologies has resulted in many recent studies, which successfully applied this technique in order to engineer microbial cells for biotechnological applications. Adaptive laboratory evolution has some major benefits as compared with classical genetic engineering but also some inherent limitations. However, recent studies show how some of the limitations may be overcome in order to successfully incorporate adaptive laboratory evolution in microbial cell factory design. Over the last two decades important insights into nutrient and stress metabolism of relevant model species were acquired, whereas some other aspects such as niche-specific differences of non-conventional cell factories are not completely understood. Altogether the current status and its future perspectives highlight the importance and potential of adaptive laboratory evolution as approach in biotechnological engineering.
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Affiliation(s)
- Martin Dragosits
- Department of Chemistry, University of Natural Resources and Life Sciences, Muthgasse 11, A-1190 Vienna, Austria.
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62
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Nielsen J, Larsson C, van Maris A, Pronk J. Metabolic engineering of yeast for production of fuels and chemicals. Curr Opin Biotechnol 2013; 24:398-404. [DOI: 10.1016/j.copbio.2013.03.023] [Citation(s) in RCA: 235] [Impact Index Per Article: 21.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/27/2012] [Revised: 03/18/2013] [Accepted: 03/27/2013] [Indexed: 01/01/2023]
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63
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Buijs NA, Siewers V, Nielsen J. Advanced biofuel production by the yeast Saccharomyces cerevisiae. Curr Opin Chem Biol 2013; 17:480-8. [DOI: 10.1016/j.cbpa.2013.03.036] [Citation(s) in RCA: 116] [Impact Index Per Article: 10.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/15/2012] [Revised: 03/06/2013] [Accepted: 03/28/2013] [Indexed: 10/26/2022]
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González-Ramos D, van den Broek M, van Maris AJA, Pronk JT, Daran JMG. Genome-scale analyses of butanol tolerance in Saccharomyces cerevisiae reveal an essential role of protein degradation. BIOTECHNOLOGY FOR BIOFUELS 2013; 6:48. [PMID: 23552365 PMCID: PMC3621596 DOI: 10.1186/1754-6834-6-48] [Citation(s) in RCA: 58] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/18/2013] [Accepted: 03/22/2013] [Indexed: 05/04/2023]
Abstract
BACKGROUND n-Butanol and isobutanol produced from biomass-derived sugars are promising renewable transport fuels and solvents. Saccharomyces cerevisiae has been engineered for butanol production, but its high butanol sensitivity poses an upper limit to product titers that can be reached by further pathway engineering. A better understanding of the molecular basis of butanol stress and tolerance of S. cerevisiae is important for achieving improved tolerance. RESULTS By combining a screening of the haploid S. cerevisiae knock-out library, gene overexpression, and genome analysis of evolutionary engineered n-butanol-tolerant strains, we established that protein degradation plays an essential role in tolerance. Strains deleted in genes involved in the ubiquitin-proteasome system and in vacuolar degradation of damaged proteins showed hypersensitivity to n-butanol. Overexpression of YLR224W, encoding the subunit responsible for the recognition of damaged proteins of an ubiquitin ligase complex, resulted in a strain with a higher n-butanol tolerance. Two independently evolved n-butanol-tolerant strains carried different mutations in both RPN4 and RTG1, which encode transcription factors involved in the expression of proteasome and peroxisomal genes, respectively. Introduction of these mutated alleles in the reference strain increased butanol tolerance, confirming their relevance in the higher tolerance phenotype. The evolved strains, in addition to n-butanol, were also more tolerant to 2-butanol, isobutanol and 1-propanol, indicating a common molecular basis for sensitivity and tolerance to C3 and C4 alcohols. CONCLUSIONS This study shows that maintenance of protein integrity plays an essential role in butanol tolerance and demonstrates new promising targets to engineer S. cerevisiae for improved tolerance.
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Affiliation(s)
- Daniel González-Ramos
- Department of Biotechnology, Delft University of Technology, Julianalaan 67, Delft 2628 BC, The Netherlands
- Kluyver Centre for Genomics of Industrial Fermentation, P.O. Box 5057, Delft 2600 GA, The Netherlands
| | - Marcel van den Broek
- Department of Biotechnology, Delft University of Technology, Julianalaan 67, Delft 2628 BC, The Netherlands
- Kluyver Centre for Genomics of Industrial Fermentation, P.O. Box 5057, Delft 2600 GA, The Netherlands
| | - Antonius JA van Maris
- Department of Biotechnology, Delft University of Technology, Julianalaan 67, Delft 2628 BC, The Netherlands
- Kluyver Centre for Genomics of Industrial Fermentation, P.O. Box 5057, Delft 2600 GA, The Netherlands
| | - Jack T Pronk
- Department of Biotechnology, Delft University of Technology, Julianalaan 67, Delft 2628 BC, The Netherlands
- Kluyver Centre for Genomics of Industrial Fermentation, P.O. Box 5057, Delft 2600 GA, The Netherlands
- Platform for Green Synthetic Biology, P.O. Box 5057, Delft 2600 GA, The Netherlands
| | - Jean-Marc G Daran
- Department of Biotechnology, Delft University of Technology, Julianalaan 67, Delft 2628 BC, The Netherlands
- Kluyver Centre for Genomics of Industrial Fermentation, P.O. Box 5057, Delft 2600 GA, The Netherlands
- Platform for Green Synthetic Biology, P.O. Box 5057, Delft 2600 GA, The Netherlands
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