51
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Sunwoo I, Kwon JE, Nguyen TH, Jeong GT, Kim SK. Ethanol production from water hyacinth (Eichhornia crassipes) hydrolysate by hyper-thermal acid hydrolysis, enzymatic saccharification and yeasts adapted to high concentration of xylose. Bioprocess Biosyst Eng 2019; 42:1367-1374. [DOI: 10.1007/s00449-019-02136-3] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/17/2019] [Accepted: 04/24/2019] [Indexed: 11/24/2022]
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52
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McTaggart TL, Bever D, Bassett S, Da Silva NA. Synthesis of polyketides from low cost substrates by the thermotolerant yeast
Kluyveromyces marxianus. Biotechnol Bioeng 2019; 116:1721-1730. [DOI: 10.1002/bit.26976] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/23/2018] [Revised: 03/07/2019] [Accepted: 03/21/2019] [Indexed: 12/12/2022]
Affiliation(s)
- Tami L. McTaggart
- Department of Chemical and Biomolecular Engineering University of California Irvine California
| | - Danielle Bever
- Department of Chemical and Biomolecular Engineering University of California Irvine California
| | - Shane Bassett
- Department of Chemical and Biomolecular Engineering University of California Irvine California
| | - Nancy A. Da Silva
- Department of Chemical and Biomolecular Engineering University of California Irvine California
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53
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Shen F, Sun R, Yao J, Li J, Liu Q, Price ND, Liu C, Wang Z. OptRAM: In-silico strain design via integrative regulatory-metabolic network modeling. PLoS Comput Biol 2019; 15:e1006835. [PMID: 30849073 PMCID: PMC6426274 DOI: 10.1371/journal.pcbi.1006835] [Citation(s) in RCA: 30] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/15/2018] [Revised: 03/20/2019] [Accepted: 02/01/2019] [Indexed: 02/07/2023] Open
Abstract
The ultimate goal of metabolic engineering is to produce desired compounds on an industrial scale in a cost effective manner. To address challenges in metabolic engineering, computational strain optimization algorithms based on genome-scale metabolic models have increasingly been used to aid in overproducing products of interest. However, most of these strain optimization algorithms utilize a metabolic network alone, with few approaches providing strategies that also include transcriptional regulation. Moreover previous integrated approaches generally require a pre-existing regulatory network. In this study, we developed a novel strain design algorithm, named OptRAM (Optimization of Regulatory And Metabolic Networks), which can identify combinatorial optimization strategies including overexpression, knockdown or knockout of both metabolic genes and transcription factors. OptRAM is based on our previous IDREAM integrated network framework, which makes it able to deduce a regulatory network from data. OptRAM uses simulated annealing with a novel objective function, which can ensure a favorable coupling between desired chemical and cell growth. The other advance we propose is a systematic evaluation metric of multiple solutions, by considering the essential genes, flux variation, and engineering manipulation cost. We applied OptRAM to generate strain designs for succinate, 2,3-butanediol, and ethanol overproduction in yeast, which predicted high minimum predicted target production rate compared with other methods and previous literature values. Moreover, most of the genes and TFs proposed to be altered by OptRAM in these scenarios have been validated by modification of the exact genes or the target genes regulated by the TFs, for overproduction of these desired compounds by in vivo experiments cataloged in the LASER database. Particularly, we successfully validated the predicted strain optimization strategy for ethanol production by fermentation experiment. In conclusion, OptRAM can provide a useful approach that leverages an integrated transcriptional regulatory network and metabolic network to guide metabolic engineering applications.
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Affiliation(s)
- Fangzhou Shen
- Bio-X Institutes, Key laboratory for the Genetics of Developmental and Neuropsychiatric Disorders (Ministry of Education), Shanghai Jiao Tong University, Shanghai, China
- School of Life Sciences and Biotechnology, Shanghai Jiao Tong University, Shanghai, China
- Department of Biomedical Engineering, University of Michigan, Ann Arbor, Michigan, United States of America
| | - Renliang Sun
- Bio-X Institutes, Key laboratory for the Genetics of Developmental and Neuropsychiatric Disorders (Ministry of Education), Shanghai Jiao Tong University, Shanghai, China
- School of Life Sciences and Biotechnology, Shanghai Jiao Tong University, Shanghai, China
| | - Jie Yao
- School of Life Sciences and Biotechnology, Shanghai Jiao Tong University, Shanghai, China
| | - Jian Li
- Bio-X Institutes, Key laboratory for the Genetics of Developmental and Neuropsychiatric Disorders (Ministry of Education), Shanghai Jiao Tong University, Shanghai, China
- School of Life Sciences and Biotechnology, Shanghai Jiao Tong University, Shanghai, China
| | - Qian Liu
- School of Life Sciences and Biotechnology, Shanghai Jiao Tong University, Shanghai, China
| | - Nathan D. Price
- Institute for Systems Biology, Seattle, Washington, United States of America
| | - Chenguang Liu
- School of Life Sciences and Biotechnology, Shanghai Jiao Tong University, Shanghai, China
| | - Zhuo Wang
- Bio-X Institutes, Key laboratory for the Genetics of Developmental and Neuropsychiatric Disorders (Ministry of Education), Shanghai Jiao Tong University, Shanghai, China
- School of Life Sciences and Biotechnology, Shanghai Jiao Tong University, Shanghai, China
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54
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Myers KS, Riley NM, MacGilvray ME, Sato TK, McGee M, Heilberger J, Coon JJ, Gasch AP. Rewired cellular signaling coordinates sugar and hypoxic responses for anaerobic xylose fermentation in yeast. PLoS Genet 2019; 15:e1008037. [PMID: 30856163 PMCID: PMC6428351 DOI: 10.1371/journal.pgen.1008037] [Citation(s) in RCA: 22] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/10/2018] [Revised: 03/21/2019] [Accepted: 02/20/2019] [Indexed: 01/08/2023] Open
Abstract
Microbes can be metabolically engineered to produce biofuels and biochemicals, but rerouting metabolic flux toward products is a major hurdle without a systems-level understanding of how cellular flux is controlled. To understand flux rerouting, we investigated a panel of Saccharomyces cerevisiae strains with progressive improvements in anaerobic fermentation of xylose, a sugar abundant in sustainable plant biomass used for biofuel production. We combined comparative transcriptomics, proteomics, and phosphoproteomics with network analysis to understand the physiology of improved anaerobic xylose fermentation. Our results show that upstream regulatory changes produce a suite of physiological effects that collectively impact the phenotype. Evolved strains show an unusual co-activation of Protein Kinase A (PKA) and Snf1, thus combining responses seen during feast on glucose and famine on non-preferred sugars. Surprisingly, these regulatory changes were required to mount the hypoxic response when cells were grown on xylose, revealing a previously unknown connection between sugar source and anaerobic response. Network analysis identified several downstream transcription factors that play a significant, but on their own minor, role in anaerobic xylose fermentation, consistent with the combinatorial effects of small-impact changes. We also discovered that different routes of PKA activation produce distinct phenotypes: deletion of the RAS/PKA inhibitor IRA2 promotes xylose growth and metabolism, whereas deletion of PKA inhibitor BCY1 decouples growth from metabolism to enable robust fermentation without division. Comparing phosphoproteomic changes across ira2Δ and bcy1Δ strains implicated regulatory changes linked to xylose-dependent growth versus metabolism. Together, our results present a picture of the metabolic logic behind anaerobic xylose flux and suggest that widespread cellular remodeling, rather than individual metabolic changes, is an important goal for metabolic engineering.
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Affiliation(s)
- Kevin S. Myers
- Great Lakes Bioenergy Research Center, University of Wisconsin-Madison, Madison, WI, United States of America
| | - Nicholas M. Riley
- Department of Chemistry, University of Wisconsin-Madison, Madison, WI, United States of America
| | - Matthew E. MacGilvray
- Laboratory of Genetics, University of Wisconsin-Madison, Madison, WI, United States of America
| | - Trey K. Sato
- Great Lakes Bioenergy Research Center, University of Wisconsin-Madison, Madison, WI, United States of America
| | - Mick McGee
- Great Lakes Bioenergy Research Center, University of Wisconsin-Madison, Madison, WI, United States of America
| | - Justin Heilberger
- Great Lakes Bioenergy Research Center, University of Wisconsin-Madison, Madison, WI, United States of America
| | - Joshua J. Coon
- Department of Chemistry, University of Wisconsin-Madison, Madison, WI, United States of America
- Genome Center of Wisconsin, University of Wisconsin-Madison, Madison, WI, United States of America
- Department of Biomolecular Chemistry, University of Wisconsin-Madison, Madison, WI, United States of America
- Morgridge Institute for Research, Madison, WI, United States of America
| | - Audrey P. Gasch
- Great Lakes Bioenergy Research Center, University of Wisconsin-Madison, Madison, WI, United States of America
- Laboratory of Genetics, University of Wisconsin-Madison, Madison, WI, United States of America
- Genome Center of Wisconsin, University of Wisconsin-Madison, Madison, WI, United States of America
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55
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Enhanced ethanol production from industrial lignocellulose hydrolysates by a hydrolysate-cofermenting Saccharomyces cerevisiae strain. Bioprocess Biosyst Eng 2019; 42:883-896. [PMID: 30820665 DOI: 10.1007/s00449-019-02090-0] [Citation(s) in RCA: 17] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/05/2018] [Accepted: 02/11/2019] [Indexed: 10/27/2022]
Abstract
Industrial production of lignocellulosic ethanol requires a microorganism utilizing both hexose and pentose, and tolerating inhibitors. In this study, a hydrolysate-cofermenting Saccharomyces cerevisiae strain was obtained through one step in vivo DNA assembly of pentose-metabolizing pathway genes, followed by consecutive adaptive evolution in pentose media containing acetic acid, and direct screening in biomass hydrolysate media. The strain was able to coferment glucose and xylose in synthetic media with the respective maximal specific rates of glucose and xylose consumption, and ethanol production of 3.47, 0.38 and 1.62 g/g DW/h, with an ethanol titre of 41.07 g/L and yield of 0.42 g/g. Industrial wheat straw hydrolysate fermentation resulted in maximal specific rates of glucose and xylose consumption, and ethanol production of 2.61, 0.54 and 1.38 g/g DW/h, respectively, with an ethanol titre of 54.11 g/L and yield of 0.44 g/g. These are among the best for wheat straw hydrolysate fermentation through separate hydrolysis and cofermentation.
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56
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Gao M, Ploessl D, Shao Z. Enhancing the Co-utilization of Biomass-Derived Mixed Sugars by Yeasts. Front Microbiol 2019; 9:3264. [PMID: 30723464 PMCID: PMC6349770 DOI: 10.3389/fmicb.2018.03264] [Citation(s) in RCA: 28] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/25/2018] [Accepted: 12/14/2018] [Indexed: 12/11/2022] Open
Abstract
Plant biomass is a promising carbon source for producing value-added chemicals, including transportation biofuels, polymer precursors, and various additives. Most engineered microbial hosts and a select group of wild-type species can metabolize mixed sugars including oligosaccharides, hexoses, and pentoses that are hydrolyzed from plant biomass. However, most of these microorganisms consume glucose preferentially to non-glucose sugars through mechanisms generally defined as carbon catabolite repression. The current lack of simultaneous mixed-sugar utilization limits achievable titers, yields, and productivities. Therefore, the development of microbial platforms capable of fermenting mixed sugars simultaneously from biomass hydrolysates is essential for economical industry-scale production, particularly for compounds with marginal profits. This review aims to summarize recent discoveries and breakthroughs in the engineering of yeast cell factories for improved mixed-sugar co-utilization based on various metabolic engineering approaches. Emphasis is placed on enhanced non-glucose utilization, discovery of novel sugar transporters free from glucose repression, native xylose-utilizing microbes, consolidated bioprocessing (CBP), improved cellulase secretion, and creation of microbial consortia for improving mixed-sugar utilization. Perspectives on the future development of biorenewables industry are provided in the end.
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Affiliation(s)
- Meirong Gao
- Department of Chemical and Biological Engineering, Iowa State University, Ames, IA, United States.,NSF Engineering Research Center for Biorenewable Chemicals (CBiRC), Iowa State University, Ames, IA, United States
| | - Deon Ploessl
- Department of Chemical and Biological Engineering, Iowa State University, Ames, IA, United States.,NSF Engineering Research Center for Biorenewable Chemicals (CBiRC), Iowa State University, Ames, IA, United States
| | - Zengyi Shao
- Department of Chemical and Biological Engineering, Iowa State University, Ames, IA, United States.,NSF Engineering Research Center for Biorenewable Chemicals (CBiRC), Iowa State University, Ames, IA, United States.,The Ames Laboratory, Iowa State University, Ames, IA, United States.,The Interdisciplinary Microbiology Program, Biorenewables Research Laboratory, Iowa State University, Ames, IA, United States
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57
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Cunha JT, Soares PO, Romaní A, Thevelein JM, Domingues L. Xylose fermentation efficiency of industrial Saccharomyces cerevisiae yeast with separate or combined xylose reductase/xylitol dehydrogenase and xylose isomerase pathways. BIOTECHNOLOGY FOR BIOFUELS 2019; 12:20. [PMID: 30705706 PMCID: PMC6348659 DOI: 10.1186/s13068-019-1360-8] [Citation(s) in RCA: 68] [Impact Index Per Article: 13.6] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/20/2018] [Accepted: 01/18/2019] [Indexed: 05/12/2023]
Abstract
BACKGROUND Xylose isomerase (XI) and xylose reductase/xylitol dehydrogenase (XR/XDH) pathways have been extensively used to confer xylose assimilation capacity to Saccharomyces cerevisiae and tackle one of the major bottlenecks in the attainment of economically viable lignocellulosic ethanol production. Nevertheless, there is a lack of studies comparing the efficiency of those pathways both separately and combined. In this work, the XI and/or XR/XDH pathways were introduced into two robust industrial S. cerevisiae strains, evaluated in synthetic media and corn cob hemicellulosic hydrolysate and the results were correlated with the differential enzyme activities found in the xylose-pathway engineered strains. RESULTS The sole expression of XI was found to increase the fermentative capacity of both strains in synthetic media at 30 °C and 40 °C: decreasing xylitol accumulation and improving xylose consumption and ethanol production. Similar results were observed in fermentations of detoxified hydrolysate. However, in the presence of lignocellulosic-derived inhibitors, a positive synergistic effect resulted from the expression of both XI and XR/XDH, possibly caused by a cofactor equilibrium between the XDH and furan detoxifying enzymes, increasing the ethanol yield by more than 38%. CONCLUSIONS This study clearly shows an advantage of using the XI from Clostridium phytofermentans to attain high ethanol productivities and yields from xylose. Furthermore, and for the first time, the simultaneous utilization of XR/XDH and XI pathways was compared to the single expression of XR/XDH or XI and was found to improve ethanol production from non-detoxified hemicellulosic hydrolysates. These results extend the knowledge regarding S. cerevisiae xylose assimilation metabolism and pave the way for the construction of more efficient strains for use in lignocellulosic industrial processes.
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Affiliation(s)
- Joana T. Cunha
- CEB-Centre of Biological Engineering, University of Minho, 4710-057 Braga, Portugal
| | - Pedro O. Soares
- CEB-Centre of Biological Engineering, University of Minho, 4710-057 Braga, Portugal
| | - Aloia Romaní
- CEB-Centre of Biological Engineering, University of Minho, 4710-057 Braga, Portugal
| | - Johan M. Thevelein
- Laboratory of Molecular Cell Biology, Institute of Botany and Microbiology, Department of Biology, KU Leuven, Kasteelpark Arenberg 31, 3001 Leuven-Heverlee, Flanders Belgium
- Center for Microbiology, VIB, Kasteelpark Arenberg 31, 3001 Leuven-Heverlee, Flanders Belgium
| | - Lucília Domingues
- CEB-Centre of Biological Engineering, University of Minho, 4710-057 Braga, Portugal
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58
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Endalur Gopinarayanan V, Nair NU. Pentose Metabolism in Saccharomyces cerevisiae: The Need to Engineer Global Regulatory Systems. Biotechnol J 2019; 14:e1800364. [PMID: 30171750 PMCID: PMC6452637 DOI: 10.1002/biot.201800364] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/27/2018] [Revised: 08/27/2018] [Indexed: 12/13/2022]
Abstract
Extending the host substrate range of industrially relevant microbes, such as Saccharomyces cerevisiae, has been a highly-active area of research since the conception of metabolic engineering. Yet, rational strategies that enable non-native substrate utilization in this yeast without the need for combinatorial and/or evolutionary techniques are underdeveloped. Herein, this review focuses on pentose metabolism in S. cerevisiae as a case study to highlight the challenges in this field. In the last three decades, work has focused on expressing exogenous pentose metabolizing enzymes as well as endogenous enzymes for effective pentose assimilation, growth, and biofuel production. The engineering strategies that are employed for pentose assimilation in this yeast are reviewed, and compared with metabolism and regulation of native sugar, galactose. In the case of galactose metabolism, multiple signals regulate and aid growth in the presence of the sugar. However, for pentoses that are non-native, it is unclear if similar growth and regulatory signals are activated. Such a comparative analysis aids in identifying missing links in xylose and arabinose utilization. While research on pentose metabolism have mostly concentrated on pathway level optimization, recent transcriptomics analyses highlight the need to consider more global regulatory, structural, and signaling components.
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Affiliation(s)
| | - Nikhil U Nair
- Department of Chemical and Biological Engineering, Tufts University, Medford, MA, 02155, U.S.A
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59
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Kobayashi J, Sasaki D, Bamba T, Hasunuma T, Kondo A. Sustainable production of glutathione from lignocellulose-derived sugars using engineered Saccharomyces cerevisiae. Appl Microbiol Biotechnol 2018; 103:1243-1254. [DOI: 10.1007/s00253-018-9493-4] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/06/2018] [Revised: 10/24/2018] [Accepted: 10/29/2018] [Indexed: 12/15/2022]
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60
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Wang X, Yang J, Yang S, Jiang Y. Unraveling the genetic basis of fast
l
‐arabinose consumption on top of recombinant xylose‐fermenting
Saccharomyces cerevisiae. Biotechnol Bioeng 2018; 116:283-293. [DOI: 10.1002/bit.26827] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/09/2018] [Revised: 08/20/2018] [Accepted: 08/30/2018] [Indexed: 12/25/2022]
Affiliation(s)
- Xin Wang
- Key Laboratory of Synthetic BiologyInstitute of Plant Physiology and Ecology, Shanghai Institutes for Biological Sciences, Chinese Academy of SciencesShanghai China
- University of Chinese Academy of SciencesBeijing China
| | - Junjie Yang
- Key Laboratory of Synthetic BiologyInstitute of Plant Physiology and Ecology, Shanghai Institutes for Biological Sciences, Chinese Academy of SciencesShanghai China
| | - Sheng Yang
- Key Laboratory of Synthetic BiologyInstitute of Plant Physiology and Ecology, Shanghai Institutes for Biological Sciences, Chinese Academy of SciencesShanghai China
- Shanghai Research and Development Center of Industrial BiotechnologyShanghai China
- Jiangsu National Synergetic Innovation Center for Advanced Materials (SICAM)Nanjing China
| | - Yu Jiang
- Key Laboratory of Synthetic BiologyInstitute of Plant Physiology and Ecology, Shanghai Institutes for Biological Sciences, Chinese Academy of SciencesShanghai China
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61
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Uranukul B, Woolston BM, Fink GR, Stephanopoulos G. Biosynthesis of monoethylene glycol in Saccharomyces cerevisiae utilizing native glycolytic enzymes. Metab Eng 2018; 51:20-31. [PMID: 30268818 DOI: 10.1016/j.ymben.2018.09.012] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/04/2018] [Revised: 09/07/2018] [Accepted: 09/25/2018] [Indexed: 10/28/2022]
Abstract
Monoethylene glycol (MEG) is an important commodity chemical with applications in numerous industrial processes, primarily in the manufacture of polyethylene terephthalate (PET) polyester used in packaging applications. In the drive towards a sustainable chemical industry, bio-based production of MEG from renewable biomass has attracted growing interest. Recent attempts for bio-based MEG production have investigated metabolic network modifications in Escherichia coli, specifically rewiring the xylose assimilation pathways for the synthesis of MEG. In the present study, we examined the suitability of Saccharomyces cerevisiae, a preferred organism for industrial applications, as platform for MEG biosynthesis. Based on combined genetic, biochemical and fermentation studies, we report evidence for the existence of an endogenous biosynthetic route for MEG production from D-xylose in S. cerevisiae which consists of phosphofructokinase and fructose-bisphosphate aldolase, the two key enzymes in the glycolytic pathway. Further metabolic engineering and process optimization yielded a strain capable of producing up to 4.0 g/L MEG, which is the highest titer reported in yeast to-date.
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Affiliation(s)
- Boonsom Uranukul
- Department of Chemical Engineering, Massachusetts Institute of Technology, Cambridge, MA 02139, United States; Whitehead Institute for Biomedical Research, Cambridge, MA 02139, United States
| | - Benjamin M Woolston
- Department of Chemical Engineering, Massachusetts Institute of Technology, Cambridge, MA 02139, United States
| | - Gerald R Fink
- Whitehead Institute for Biomedical Research, Cambridge, MA 02139, United States
| | - Gregory Stephanopoulos
- Department of Chemical Engineering, Massachusetts Institute of Technology, Cambridge, MA 02139, United States.
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Merkx-Jacques A, Rasmussen H, Muise DM, Benjamin JJR, Kottwitz H, Tanner K, Milway MT, Purdue LM, Scaife MA, Armenta RE, Woodhall DL. Engineering xylose metabolism in thraustochytrid T18. BIOTECHNOLOGY FOR BIOFUELS 2018; 11:248. [PMID: 30237825 PMCID: PMC6139898 DOI: 10.1186/s13068-018-1246-1] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 01/26/2018] [Accepted: 08/27/2018] [Indexed: 06/08/2023]
Abstract
BACKGROUND Thraustochytrids are heterotrophic, oleaginous, marine protists with a significant potential for biofuel production. High-value co-products can off-set production costs; however, the cost of raw materials, and in particular carbon, is a major challenge to developing an economical viable production process. The use of hemicellulosic carbon derived from agricultural waste, which is rich in xylose and glucose, has been proposed as a sustainable and low-cost approach. Thraustochytrid strain T18 is a commercialized environmental isolate that readily consumes glucose, attaining impressive biomass, and oil production levels. However, neither thraustochytrid growth capabilities in the presence of xylose nor a xylose metabolic pathway has been described. The aims of this study were to identify and characterize the xylose metabolism pathway of T18 and, through genetic engineering, develop a strain capable of growth on hemicellulosic sugars. RESULTS Characterization of T18 performance in glucose/xylose media revealed diauxic growth and copious extracellular xylitol production. Furthermore, T18 did not grow in media containing xylose as the only carbon source. We identified, cloned, and functionally characterized a xylose isomerase. Transcriptomics indicated that this xylose isomerase gene is upregulated when xylose is consumed by the cells. Over-expression of the native xylose isomerase in T18, creating strain XI 16, increased xylose consumption from 5.2 to 7.6 g/L and reduced extracellular xylitol from almost 100% to 68%. Xylose utilization efficiency of this strain was further enhanced by over-expressing a heterologous xylulose kinase to reduce extracellular xylitol to 20%. Moreover, the ability to grow in media containing xylose as a sole sugar was dependent on the copy number of both xylose isomerase and xylulose kinase present. In fed-batch fermentations, the best xylose metabolizing isolate, XI-XK 7, used 137 g of xylose versus 39 g by wild type and produced more biomass and fatty acid. CONCLUSIONS The presence of a typically prokaryotic xylose isomerase and xylitol production through a typically eukaryotic xylose reductase pathway in T18 is the first report of an organism naturally encoding enzymes from two native xylose metabolic pathways. Our newly engineered strains pave the way for the growth of T18 on waste hemicellulosic feedstocks for biofuel production.
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Affiliation(s)
| | - Holly Rasmussen
- Mara Renewables Corporation, 101 Research Drive, Dartmouth, NS B2Y 4T6 Canada
| | - Denise M. Muise
- Mara Renewables Corporation, 101 Research Drive, Dartmouth, NS B2Y 4T6 Canada
| | | | - Haila Kottwitz
- Mara Renewables Corporation, 101 Research Drive, Dartmouth, NS B2Y 4T6 Canada
| | - Kaitlyn Tanner
- Mara Renewables Corporation, 101 Research Drive, Dartmouth, NS B2Y 4T6 Canada
| | - Michael T. Milway
- Mara Renewables Corporation, 101 Research Drive, Dartmouth, NS B2Y 4T6 Canada
| | - Laura M. Purdue
- Mara Renewables Corporation, 101 Research Drive, Dartmouth, NS B2Y 4T6 Canada
| | - Mark A. Scaife
- Mara Renewables Corporation, 101 Research Drive, Dartmouth, NS B2Y 4T6 Canada
| | - Roberto E. Armenta
- Mara Renewables Corporation, 101 Research Drive, Dartmouth, NS B2Y 4T6 Canada
| | - David L. Woodhall
- Mara Renewables Corporation, 101 Research Drive, Dartmouth, NS B2Y 4T6 Canada
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Papapetridis I, Verhoeven MD, Wiersma SJ, Goudriaan M, van Maris AJA, Pronk JT. Laboratory evolution for forced glucose-xylose co-consumption enables identification of mutations that improve mixed-sugar fermentation by xylose-fermenting Saccharomyces cerevisiae. FEMS Yeast Res 2018; 18:4996351. [PMID: 29771304 PMCID: PMC6001886 DOI: 10.1093/femsyr/foy056] [Citation(s) in RCA: 33] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/14/2018] [Accepted: 05/14/2018] [Indexed: 01/18/2023] Open
Abstract
Simultaneous fermentation of glucose and xylose can contribute to improved productivity and robustness of yeast-based processes for bioethanol production from lignocellulosic hydrolysates. This study explores a novel laboratory evolution strategy for identifying mutations that contribute to simultaneous utilisation of these sugars in batch cultures of Saccharomyces cerevisiae. To force simultaneous utilisation of xylose and glucose, the genes encoding glucose-6-phosphate isomerase (PGI1) and ribulose-5-phosphate epimerase (RPE1) were deleted in a xylose-isomerase-based xylose-fermenting strain with a modified oxidative pentose-phosphate pathway. Laboratory evolution of this strain in serial batch cultures on glucose-xylose mixtures yielded mutants that rapidly co-consumed the two sugars. Whole-genome sequencing of evolved strains identified mutations in HXK2, RSP5 and GAL83, whose introduction into a non-evolved xylose-fermenting S. cerevisiae strain improved co-consumption of xylose and glucose under aerobic and anaerobic conditions. Combined deletion of HXK2 and introduction of a GAL83G673T allele yielded a strain with a 2.5-fold higher xylose and glucose co-consumption ratio than its xylose-fermenting parental strain. These two modifications decreased the time required for full sugar conversion in anaerobic bioreactor batch cultures, grown on 20 g L-1 glucose and 10 g L-1 xylose, by over 24 h. This study demonstrates that laboratory evolution and genome resequencing of microbial strains engineered for forced co-consumption is a powerful approach for studying and improving simultaneous conversion of mixed substrates.
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Affiliation(s)
| | | | - Sanne J Wiersma
- Delft University of Technology, Department of Biotechnology, Van der Maasweg 9, 2629 HZ Delft, The Netherlands
| | - Maaike Goudriaan
- Delft University of Technology, Department of Biotechnology, Van der Maasweg 9, 2629 HZ Delft, The Netherlands
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64
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Recombinant Diploid Saccharomyces cerevisiae Strain Development for Rapid Glucose and Xylose Co-Fermentation. FERMENTATION-BASEL 2018. [DOI: 10.3390/fermentation4030059] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
Cost-effective production of cellulosic ethanol requires robust microorganisms for rapid co-fermentation of glucose and xylose. This study aims to develop a recombinant diploid xylose-fermenting Saccharomyces cerevisiae strain for efficient conversion of lignocellulosic biomass sugars to ethanol. Episomal plasmids harboring codon-optimized Piromyces sp. E2 xylose isomerase (PirXylA) and Orpinomyces sp. ukk1 xylose (OrpXylA) genes were constructed and transformed into S. cerevisiae. The strain harboring plasmids with tandem PirXylA was favorable for xylose utilization when xylose was used as the sole carbon source, while the strain harboring plasmids with tandem OrpXylA was beneficial for glucose and xylose cofermentation. PirXylA and OrpXylA genes were also individually integrated into the genome of yeast strains in multiple copies. Such integration was beneficial for xylose alcoholic fermentation. The respiration-deficient strain carrying episomal or integrated OrpXylA genes exhibited the best performance for glucose and xylose co-fermentation. This was partly attributed to the high expression levels and activities of xylose isomerase. Mating a respiration-efficient strain carrying the integrated PirXylA gene with a respiration-deficient strain harboring integrated OrpXylA generated a diploid recombinant xylose-fermenting yeast strain STXQ with enhanced cell growth and xylose fermentation. Co-fermentation of 162 g L−1 glucose and 95 g L−1 xylose generated 120.6 g L−1 ethanol in 23 h, with sugar conversion higher than 99%, ethanol yield of 0.47 g g−1, and ethanol productivity of 5.26 g L−1·h−1.
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Verhoeven MD, de Valk SC, Daran JMG, van Maris AJA, Pronk JT. Fermentation of glucose-xylose-arabinose mixtures by a synthetic consortium of single-sugar-fermenting Saccharomyces cerevisiae strains. FEMS Yeast Res 2018; 18:5054444. [DOI: 10.1093/femsyr/foy075] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/08/2018] [Accepted: 07/13/2018] [Indexed: 11/15/2022] Open
Affiliation(s)
- Maarten D Verhoeven
- 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
| | - Jean-Marc G Daran
- Department of Biotechnology, Delft University of Technology, Van der Maasweg 9, 2629 HZ Delft, The Netherlands
| | - Antonius J A van Maris
- 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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Lane S, Dong J, Jin YS. Value-added biotransformation of cellulosic sugars by engineered Saccharomyces cerevisiae. BIORESOURCE TECHNOLOGY 2018; 260:380-394. [PMID: 29655899 DOI: 10.1016/j.biortech.2018.04.013] [Citation(s) in RCA: 27] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/01/2018] [Revised: 03/31/2018] [Accepted: 04/02/2018] [Indexed: 05/26/2023]
Abstract
The substantial research efforts into lignocellulosic biofuels have generated an abundance of valuable knowledge and technologies for metabolic engineering. In particular, these investments have led to a vast growth in proficiency of engineering the yeast Saccharomyces cerevisiae for consuming lignocellulosic sugars, enabling the simultaneous assimilation of multiple carbon sources, and producing a large variety of value-added products by introduction of heterologous metabolic pathways. While microbial conversion of cellulosic sugars into large-volume low-value biofuels is not currently economically feasible, there may still be opportunities to produce other value-added chemicals as regulation of cellulosic sugar metabolism is quite different from glucose metabolism. This review summarizes these recent advances with an emphasis on employing engineered yeast for the bioconversion of lignocellulosic sugars into a variety of non-ethanol value-added products.
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Affiliation(s)
- Stephan Lane
- Carl Woese Institute for Genomic Biology, University of Illinois at Urbana-Champaign, Urbana, IL, USA; Department of Food Science and Human Nutrition, University of Illinois at Urbana-Champaign, Urbana, IL, USA
| | - Jia Dong
- Department of Crop Sciences, University of Illinois at Urbana-Champaign, Urbana, IL, USA
| | - Yong-Su Jin
- Carl Woese Institute for Genomic Biology, University of Illinois at Urbana-Champaign, Urbana, IL, USA; Department of Food Science and Human Nutrition, University of Illinois at Urbana-Champaign, Urbana, IL, USA.
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Optimizing the coordinated transcription of central xylose-metabolism genes in Saccharomyces cerevisiae. Appl Microbiol Biotechnol 2018; 102:7207-7217. [PMID: 29946930 DOI: 10.1007/s00253-018-9172-5] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/15/2018] [Revised: 06/06/2018] [Accepted: 06/10/2018] [Indexed: 10/28/2022]
Abstract
The efficient fermentation of xylose can improve biofuel production. We previously developed a two-stage transcriptional reprogramming (TSTR) strategy (including a glucose fermentation stage and a xylose fermentation stage) and demonstrated its application for the construction of Saccharomyces cerevisiae strains with efficient xylose utilization. In this study, we used these as initial strains to assess the effects of copy number variation (CNV) on optimal gene expression and rewiring the redox balance of the xylose utilization pathway. We obtained strains that contained several integrated copies of XYL1, XYL2, and XKS1 and showed increased ethanol yields. An examination of the individual and combined effects of CNVs of key genes and the redox balance pathway revealed that the TSTR strategy improves ethanol production efficiency. Furthermore, XYL1 or XYL2 overexpression was related to improved xylose utilization. These results showed that strains with faster growth and/or higher ethanol production produced more ethanol from xylose via the synthetic xylose-assimilation pathway. Accordingly, TSTR is an effective strategy to improve xylose metabolism in industrial yeast strains.
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Co-fermentation of cellobiose and xylose by mixed culture of recombinant Saccharomyces cerevisiae and kinetic modeling. PLoS One 2018; 13:e0199104. [PMID: 29940003 PMCID: PMC6016917 DOI: 10.1371/journal.pone.0199104] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/01/2018] [Accepted: 05/31/2018] [Indexed: 11/19/2022] Open
Abstract
Efficient conversion of cellulosic sugars in cellulosic hydrolysates is important for economically viable production of biofuels from lignocellulosic biomass, but the goal remains a critical challenge. The present study reports a new approach for simultaneous fermentation of cellobiose and xylose by using the co-culture consisting of recombinant Saccharomyces cerevisiae specialist strains. The co-culture system can provide competitive advantage of modularity compared to the single culture system and can be tuned to deal with fluctuations in feedstock composition to achieve robust and cost-effective biofuel production. This study characterized fermentation kinetics of the recombinant cellobiose-consuming S. cerevisiae strain EJ2, xylose-consuming S. cerevisiae strain SR8, and their co-culture. The motivation for kinetic modeling was to provide guidance and prediction of using the co-culture system for simultaneous fermentation of mixed sugars with adjustable biomass of each specialist strain under different substrate concentrations. The kinetic model for the co-culture system was developed based on the pure culture models and incorporated the effects of product inhibition, initial substrate concentration and inoculum size. The model simulations were validated by results from independent fermentation experiments under different substrate conditions, and good agreement was found between model predictions and experimental data from batch fermentation of cellobiose, xylose and their mixtures. Additionally, with the guidance of model prediction, simultaneous co-fermentation of 60 g/L cellobiose and 20 g/L xylose was achieved with the initial cell densities of 0.45 g dry cell weight /L for EJ2 and 0.9 g dry cell weight /L SR8. The results demonstrated that the kinetic modeling could be used to guide the design and optimization of yeast co-culture conditions for achieving simultaneous fermentation of cellobiose and xylose with improved ethanol productivity, which is critically important for robust and efficient renewable biofuel production from lignocellulosic biomass.
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Robak K, Balcerek M. Review of Second Generation Bioethanol Production from Residual Biomass. Food Technol Biotechnol 2018; 56:174-187. [PMID: 30228792 PMCID: PMC6117988 DOI: 10.17113/ftb.56.02.18.5428] [Citation(s) in RCA: 154] [Impact Index Per Article: 25.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/18/2017] [Accepted: 01/11/2018] [Indexed: 11/12/2022] Open
Abstract
In the context of climate change and the depletion of fossil fuels, there is a great need for alternatives to petroleum in the transport sector. This review provides an overview of the production of second generation bioethanol, which is distinguished from the first generation and subsequent generations of biofuels by its use of lignocellulosic biomass as raw material. The structural components of the lignocellulosic biomass such as cellulose, hemicellulose and lignin, are presented along with technological unit steps including pretreatment, enzymatic hydrolysis, fermentation, distillation and dehydration. The purpose of the pretreatment step is to increase the surface area of carbohydrate available for enzymatic saccharification, while minimizing the content of inhibitors. Performing the enzymatic hydrolysis releases fermentable sugars, which are converted by microbial catalysts into ethanol. The hydrolysates obtained after the pretreatment and enzymatic hydrolysis contain a wide spectrum of sugars, predominantly glucose and xylose. Genetically engineered microorganisms are therefore needed to carry out co-fermentation. The excess of harmful inhibitors in the hydrolysate, such as weak organic acids, furan derivatives and phenol components, can be removed by detoxification before fermentation. Effective saccharification further requires using exogenous hemicellulases and cellulolytic enzymes. Conventional species of distiller's yeast are unable to ferment pentoses into ethanol, and only a very few natural microorganisms, including yeast species like Candida shehatae, Pichia (Scheffersomyces) stipitis, and Pachysolen tannophilus, metabolize xylose to ethanol. Enzymatic hydrolysis and fermentation can be performed in a number of ways: by separate saccharification and fermentation, simultaneous saccharification and fermentation or consolidated bioprocessing. Pentose-fermenting microorganisms can be obtained through genetic engineering, by introducing xylose-encoding genes into metabolism of a selected microorganism to optimize its use of xylose accumulated in the hydrolysate.
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Affiliation(s)
- Katarzyna Robak
- Lodz University of Technology, Faculty of Biotechnology and Food Sciences, Institute of Fermentation Technology and Microbiology, Department of Spirit and Yeast Technology, Wolczanska 171/173, PL 90-924 Lodz, Poland
| | - Maria Balcerek
- Lodz University of Technology, Faculty of Biotechnology and Food Sciences, Institute of Fermentation Technology and Microbiology, Department of Spirit and Yeast Technology, Wolczanska 171/173, PL 90-924 Lodz, Poland
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Guo J, Huang S, Chen Y, Guo X, Xiao D. Heterologous expression of Spathaspora passalidarum xylose reductase and xylitol dehydrogenase genes improved xylose fermentation ability of Aureobasidium pullulans. Microb Cell Fact 2018; 17:64. [PMID: 29712559 PMCID: PMC5925849 DOI: 10.1186/s12934-018-0911-1] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/11/2017] [Accepted: 04/24/2018] [Indexed: 11/16/2022] Open
Abstract
Background Aureobasidium pullulans is a yeast-like fungus that can ferment xylose to generate high-value-added products, such as pullulan, heavy oil, and melanin. The combinatorial expression of two xylose reductase (XR) genes and two xylitol dehydrogenase (XDH) genes from Spathaspora passalidarum and the heterologous expression of the Piromyces sp. xylose isomerase (XI) gene were induced in A. pullulans to increase the consumption capability of A. pullulans on xylose. Results The overexpression of XYL1.2 (encoding XR) and XYL2.2 (encoding XDH) was the most beneficial for xylose utilization, resulting in a 17.76% increase in consumed xylose compared with the parent strain, whereas the introduction of the Piromyces sp. XI pathway failed to enhance xylose utilization efficiency. Mutants with superior xylose fermentation performance exhibited increased intracellular reducing equivalents. The fermentation performance of all recombinant strains was not affected when glucose or sucrose was utilized as the carbon source. The strain with overexpression of XYL1.2 and XYL2.2 exhibited excellent fermentation performance with mimicked hydrolysate, and pullulan production increased by 97.72% compared with that of the parent strain. Conclusions The present work indicates that the P4 mutant (using the XR/XDH pathway) with overexpressed XYL1.2 and XYL2.2 exhibited the best xylose fermentation performance. The P4 strain showed the highest intracellular reducing equivalents and XR and XDH activity, with consequently improved pullulan productivity and reduced melanin production. This valuable development in aerobic fermentation by the P4 strain may provide guidance for the biotransformation of xylose to high-value products by A. pullulans through genetic approach. Electronic supplementary material The online version of this article (10.1186/s12934-018-0911-1) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Jian Guo
- Key Laboratory of Industrial Fermentation Microbiology, Ministry of Education, Tianjin Industrial Microbiology Key Laboratory, College of Biotechnology, Tianjin University of Science and Technology, Tianjin, 300457, People's Republic of China
| | - Siyao Huang
- Key Laboratory of Industrial Fermentation Microbiology, Ministry of Education, Tianjin Industrial Microbiology Key Laboratory, College of Biotechnology, Tianjin University of Science and Technology, Tianjin, 300457, People's Republic of China
| | - Yefu Chen
- Key Laboratory of Industrial Fermentation Microbiology, Ministry of Education, Tianjin Industrial Microbiology Key Laboratory, College of Biotechnology, Tianjin University of Science and Technology, Tianjin, 300457, People's Republic of China.
| | - Xuewu Guo
- Key Laboratory of Industrial Fermentation Microbiology, Ministry of Education, Tianjin Industrial Microbiology Key Laboratory, College of Biotechnology, Tianjin University of Science and Technology, Tianjin, 300457, People's Republic of China
| | - Dongguang Xiao
- Key Laboratory of Industrial Fermentation Microbiology, Ministry of Education, Tianjin Industrial Microbiology Key Laboratory, College of Biotechnology, Tianjin University of Science and Technology, Tianjin, 300457, People's Republic of China
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Turner TL, Kim H, Kong II, Liu JJ, Zhang GC, Jin YS. Engineering and Evolution of Saccharomyces cerevisiae to Produce Biofuels and Chemicals. ADVANCES IN BIOCHEMICAL ENGINEERING/BIOTECHNOLOGY 2018; 162:175-215. [PMID: 27913828 DOI: 10.1007/10_2016_22] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Abstract
To mitigate global climate change caused partly by the use of fossil fuels, the production of fuels and chemicals from renewable biomass has been attempted. The conversion of various sugars from renewable biomass into biofuels by engineered baker's yeast (Saccharomyces cerevisiae) is one major direction which has grown dramatically in recent years. As well as shifting away from fossil fuels, the production of commodity chemicals by engineered S. cerevisiae has also increased significantly. The traditional approaches of biochemical and metabolic engineering to develop economic bioconversion processes in laboratory and industrial settings have been accelerated by rapid advancements in the areas of yeast genomics, synthetic biology, and systems biology. Together, these innovations have resulted in rapid and efficient manipulation of S. cerevisiae to expand fermentable substrates and diversify value-added products. Here, we discuss recent and major advances in rational (relying on prior experimentally-derived knowledge) and combinatorial (relying on high-throughput screening and genomics) approaches to engineer S. cerevisiae for producing ethanol, butanol, 2,3-butanediol, fatty acid ethyl esters, isoprenoids, organic acids, rare sugars, antioxidants, and sugar alcohols from glucose, xylose, cellobiose, galactose, acetate, alginate, mannitol, arabinose, and lactose.
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Affiliation(s)
- Timothy L Turner
- Department of Food Science and Human Nutrition, University of Illinois at Urbana-Champaign, Urbana, IL, 61801, USA
| | - Heejin Kim
- 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
| | - In Iok Kong
- 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
| | - Jing-Jing Liu
- 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
| | - Guo-Chang Zhang
- Department of Food Science and Human Nutrition, 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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Wei S, Liu Y, Wu M, Ma T, Bai X, Hou J, Shen Y, Bao X. Disruption of the transcription factors Thi2p and Nrm1p alleviates the post-glucose effect on xylose utilization in Saccharomyces cerevisiae. BIOTECHNOLOGY FOR BIOFUELS 2018; 11:112. [PMID: 29686730 PMCID: PMC5901872 DOI: 10.1186/s13068-018-1112-1] [Citation(s) in RCA: 20] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/09/2017] [Accepted: 04/06/2018] [Indexed: 05/07/2023]
Abstract
BACKGROUND The recombinant Saccharomyces cerevisiae strains that acquired the ability to utilize xylose through metabolic and evolutionary engineering exhibit good performance when xylose is the sole carbon source in the medium (designated the X stage in the present work). However, the xylose consumption rate of strains is generally low after glucose depletion during glucose-xylose co-fermentation, despite the presence of xylose in the medium (designated the GX stage in the present work). Glucose fermentation appears to reduce the capacity of these strains to "recognize" xylose during the GX stage, a phenomenon termed the post-glucose effect on xylose metabolism. RESULTS Two independent xylose-fermenting S. cerevisiae strains derived from a haploid laboratory strain and a diploid industrial strain were used in the present study. Their common characteristics were investigated to reveal the mechanism underlying the post-glucose effect and to develop methods to alleviate this effect. Both strains showed lower growth and specific xylose consumption rates during the GX stage than during the X stage. Glycolysis, the pentose phosphate pathway, and translation-related gene expression were reduced; meanwhile, genes in the tricarboxylic acid cycle and glyoxylic acid cycle demonstrated higher expression during the GX stage than during the X stage. The effects of 11 transcription factors (TFs) whose expression levels significantly differed between the GX and X stages in both strains were investigated. Knockout of THI2 promoted ribosome synthesis, and the growth rate, specific xylose utilization rate, and specific ethanol production rate of the strain increased by 17.4, 26.8, and 32.4%, respectively, in the GX stage. Overexpression of the ribosome-related genes RPL9A, RPL7B, and RPL7A also enhanced xylose utilization in a corresponding manner. Furthermore, the overexpression of NRM1, which is related to the cell cycle, increased the growth rate by 8.7%, the xylose utilization rate by 30.0%, and the ethanol production rate by 76.6%. CONCLUSIONS The TFs Thi2p and Nrm1p exerted unexpected effects on the post-glucose effect, enhancing ribosome synthesis and altering the cell cycle, respectively. The results of this study will aid in maintaining highly efficient xylose metabolism during glucose-xylose co-fermentation, which is utilized for lignocellulosic bioethanol production.
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Affiliation(s)
- Shan Wei
- State Key Laboratory of Microbial Technology, Microbiology and Biotechnology Institute, Shandong University, Shan Da Nan Road 27, Jinan, 250100 China
- School of Life Science, Shandong University, Shan Da Nan Road 27, Jinan, 250100 China
| | - Yanan Liu
- State Key Laboratory of Microbial Technology, Microbiology and Biotechnology Institute, Shandong University, Shan Da Nan Road 27, Jinan, 250100 China
- School of Life Science, Shandong University, Shan Da Nan Road 27, Jinan, 250100 China
| | - Meiling Wu
- State Key Laboratory of Microbial Technology, Microbiology and Biotechnology Institute, Shandong University, Shan Da Nan Road 27, Jinan, 250100 China
- School of Life Science, Shandong University, Shan Da Nan Road 27, Jinan, 250100 China
| | - Tiantai Ma
- State Key Laboratory of Microbial Technology, Microbiology and Biotechnology Institute, Shandong University, Shan Da Nan Road 27, Jinan, 250100 China
- School of Life Science, Shandong University, Shan Da Nan Road 27, Jinan, 250100 China
| | - Xiangzheng Bai
- State Key Laboratory of Microbial Technology, Microbiology and Biotechnology Institute, Shandong University, Shan Da Nan Road 27, Jinan, 250100 China
- School of Life Science, Shandong University, Shan Da Nan Road 27, Jinan, 250100 China
| | - Jin Hou
- State Key Laboratory of Microbial Technology, Microbiology and Biotechnology Institute, Shandong University, Shan Da Nan Road 27, Jinan, 250100 China
- School of Life Science, Shandong University, Shan Da Nan Road 27, Jinan, 250100 China
| | - Yu Shen
- State Key Laboratory of Microbial Technology, Microbiology and Biotechnology Institute, Shandong University, Shan Da Nan Road 27, Jinan, 250100 China
- School of Life Science, Shandong University, Shan Da Nan Road 27, Jinan, 250100 China
| | - Xiaoming Bao
- State Key Laboratory of Microbial Technology, Microbiology and Biotechnology Institute, Shandong University, Shan Da Nan Road 27, Jinan, 250100 China
- School of Life Science, Shandong University, Shan Da Nan Road 27, Jinan, 250100 China
- Shandong Provincial Key Laboratory of Microbial Engineering, Qi Lu University of Technology, Daxue Rd 3501, Jinan, 250353 China
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Evolutionary engineering of industrial microorganisms-strategies and applications. Appl Microbiol Biotechnol 2018; 102:4615-4627. [DOI: 10.1007/s00253-018-8937-1] [Citation(s) in RCA: 30] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/29/2017] [Revised: 03/13/2018] [Accepted: 03/13/2018] [Indexed: 10/17/2022]
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Under pressure: evolutionary engineering of yeast strains for improved performance in fuels and chemicals production. Curr Opin Biotechnol 2018; 50:47-56. [DOI: 10.1016/j.copbio.2017.10.011] [Citation(s) in RCA: 109] [Impact Index Per Article: 18.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/21/2017] [Revised: 10/31/2017] [Accepted: 10/31/2017] [Indexed: 02/01/2023]
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A semi-synthetic regulon enables rapid growth of yeast on xylose. Nat Commun 2018; 9:1233. [PMID: 29581426 PMCID: PMC5964326 DOI: 10.1038/s41467-018-03645-7] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/08/2017] [Accepted: 03/01/2018] [Indexed: 01/27/2023] Open
Abstract
Nutrient assimilation is the first step that allows biological systems to proliferate and produce value-added products. Yet, implementation of heterologous catabolic pathways has so far relied on constitutive gene expression without consideration for global regulatory systems that may enhance nutrient assimilation and cell growth. In contrast, natural systems prefer nutrient-responsive gene regulation (called regulons) that control multiple cellular functions necessary for cell survival and growth. Here, in Saccharomyces cerevisiae, by partially- and fully uncoupling galactose (GAL)-responsive regulation and metabolism, we demonstrate the significant growth benefits conferred by the GAL regulon. Next, by adapting the various aspects of the GAL regulon for a non-native nutrient, xylose, we build a semi-synthetic regulon that exhibits higher growth rate, better nutrient consumption, and improved growth fitness compared to the traditional and ubiquitous constitutive expression strategy. This work provides an elegant paradigm to integrate non-native nutrient catabolism with native, global cellular responses to support fast growth. Efficient assimilation of nutrients is essential for the production of value-added products in microbial fermentation. Here the authors design a semi-synthetic xylose regulon to improve growth characteristics of Saccharomyces cerevisiae on this non-native sugar.
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HamediRad M, Lian J, Li H, Zhao H. RNAi assisted genome evolution unveils yeast mutants with improved xylose utilization. Biotechnol Bioeng 2018; 115:1552-1560. [DOI: 10.1002/bit.26570] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/07/2017] [Revised: 01/28/2018] [Accepted: 02/08/2018] [Indexed: 12/21/2022]
Affiliation(s)
- Mohammad HamediRad
- Department of Chemical and Biomolecular EngineeringCarl R. Woese Institute for Genomic BiologyUrbanaIllinois
| | - Jiazhang Lian
- Department of Chemical and Biomolecular EngineeringCarl R. Woese Institute for Genomic BiologyUrbanaIllinois
- College of Chemical and Biological EngineeringZhejiang UniversityHangzhouChina
| | - Hejun Li
- Department of Agricultural and Biological EngineeringUniversity of Illinois at Urbana‐ChampaignUrbanaIllinois
| | - Huimin Zhao
- Department of Chemical and Biomolecular EngineeringCarl R. Woese Institute for Genomic BiologyUrbanaIllinois
- Departments of Chemistry Biochemistry and BioengineeringUniversity of Illinois at UrbanaUrbanaIllinois
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Wu R, Ma C, Zhang YHP, Zhu Z. Complete Oxidation of Xylose for Bioelectricity Generation by Reconstructing a Bacterial Xylose Utilization Pathway in vitro. ChemCatChem 2018. [DOI: 10.1002/cctc.201702018] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Affiliation(s)
- Ranran Wu
- Tianjin Institute of Industrial Biotechnology; Chinese Academy of Sciences; 32 West 7 Avenue, Tianjin Airport Economic Area Tianjin 300308 P.R. China
| | - Chunling Ma
- Tianjin Institute of Industrial Biotechnology; Chinese Academy of Sciences; 32 West 7 Avenue, Tianjin Airport Economic Area Tianjin 300308 P.R. China
| | - Y.-H. Percival Zhang
- Tianjin Institute of Industrial Biotechnology; Chinese Academy of Sciences; 32 West 7 Avenue, Tianjin Airport Economic Area Tianjin 300308 P.R. China
| | - Zhiguang Zhu
- Tianjin Institute of Industrial Biotechnology; Chinese Academy of Sciences; 32 West 7 Avenue, Tianjin Airport Economic Area Tianjin 300308 P.R. China
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xylA and xylB overexpression as a successful strategy for improving xylose utilization and poly-3-hydroxybutyrate production in Burkholderia sacchari. ACTA ACUST UNITED AC 2018; 45:165-173. [DOI: 10.1007/s10295-018-2007-7] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/03/2017] [Accepted: 01/08/2018] [Indexed: 12/31/2022]
Abstract
Abstract
Despite the versatility and many advantages of polyhydroxyalkanoates as petroleum-based plastic substitutes, their higher production cost compared to petroleum-based polymers has historically limited their large-scale production. One appealing approach to reducing production costs is to employ less expensive, renewable feedstocks. Xylose, for example is an abundant and inexpensive carbon source derived from hemicellulosic residues abundant in agro-industrial waste (sugarcane bagasse hemicellulosic hydrolysates). In this work, the production of poly-3-hydroxybutyrate P(3HB) from xylose was studied to develop technologies for conversion of agro-industrial waste into high-value chemicals and biopolymers. Specifically, this work elucidates the organization of the xylose assimilation operon of Burkholderia sacchari, a non-model bacterium with high capacity for P(3HB) accumulation. Overexpression of endogenous xylose isomerase and xylulokinase genes was successfully assessed, improving both specific growth rate and P(3HB) production. Compared to control strain (harboring pBBR1MCS-2), xylose utilization in the engineered strain was substantially improved with 25% increase in specific growth rate, 34% increase in P(3HB) production, and the highest P(3HB) yield from xylose reported to date for B. sacchari (Y P3HB/Xil = 0.35 g/g). This study highlights that xylA and xylB overexpression is an effective strategy to improve xylose utilization and P(3HB) production in B. sacchari.
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The Role of Yeast-Surface-Display Techniques in Creating Biocatalysts for Consolidated BioProcessing. Catalysts 2018. [DOI: 10.3390/catal8030094] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022] Open
Abstract
Climate change is directly linked to the rapid depletion of our non-renewable fossil resources and has posed concerns on sustainability. Thus, imploring the need for us to shift from our fossil based economy to a sustainable bioeconomy centered on biomass utilization. The efficient bioconversion of lignocellulosic biomass (an ideal feedstock) to a platform chemical, such as bioethanol, can be achieved via the consolidated bioprocessing technology, termed yeast surface engineering, to produce yeasts that are capable of this feat. This approach has various strategies that involve the display of enzymes on the surface of yeast to degrade the lignocellulosic biomass, then metabolically convert the degraded sugars directly into ethanol, thus elevating the status of yeast from an immobilization material to a whole-cell biocatalyst. The performance of the engineered strains developed from these strategies are presented, visualized, and compared in this article to highlight the role of this technology in moving forward to our quest against climate change. Furthermore, the qualitative assessment synthesized in this work can serve as a reference material on addressing the areas of improvement of the field and on assessing the capability and potential of the different yeast surface display strategies on the efficient degradation, utilization, and ethanol production from lignocellulosic biomass.
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Cheng C, Tang RQ, Xiong L, Hector RE, Bai FW, Zhao XQ. Association of improved oxidative stress tolerance and alleviation of glucose repression with superior xylose-utilization capability by a natural isolate of Saccharomyces cerevisiae. BIOTECHNOLOGY FOR BIOFUELS 2018; 11:28. [PMID: 29441126 PMCID: PMC5798184 DOI: 10.1186/s13068-018-1018-y] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 08/08/2017] [Accepted: 01/11/2018] [Indexed: 06/08/2023]
Abstract
BACKGROUND Saccharomyces cerevisiae wild strains generally have poor xylose-utilization capability, which is a major barrier for efficient bioconversion of lignocellulosic biomass. Laboratory adaption is commonly used to enhance xylose utilization of recombinant S. cerevisiae. Apparently, yeast cells could remodel the metabolic network for xylose metabolism. However, it still remains unclear why natural isolates of S. cerevisiae poorly utilize xylose. Here, we analyzed a unique S. cerevisiae natural isolate YB-2625 which has superior xylose metabolism capability in the presence of mixed-sugar. Comparative transcriptomic analysis was performed using S. cerevisiae YB-2625 grown in a mixture of glucose and xylose, and the model yeast strain S288C served as a control. Global gene transcription was compared at both the early mixed-sugar utilization stage and the latter xylose-utilization stage. RESULTS Genes involved in endogenous xylose-assimilation (XYL2 and XKS1), gluconeogenesis, and TCA cycle showed higher transcription levels in S. cerevisiae YB-2625 at the xylose-utilization stage, when compared to the reference strain. On the other hand, transcription factor encoding genes involved in regulation of glucose repression (MIG1, MIG2, and MIG3) as well as HXK2 displayed decreased transcriptional levels in YB-2625, suggesting the alleviation of glucose repression of S. cerevisiae YB-2625. Notably, genes encoding antioxidant enzymes (CTT1, CTA1, SOD2, and PRX1) showed higher transcription levels in S. cerevisiae YB-2625 in the xylose-utilization stage than that of the reference strain. Consistently, catalase activity of YB-2625 was 1.9-fold higher than that of S. cerevisiae S288C during the xylose-utilization stage. As a result, intracellular reactive oxygen species levels of S. cerevisiae YB-2625 were 43.3 and 58.6% lower than that of S288C at both sugar utilization stages. Overexpression of CTT1 and PRX1 in the recombinant strain S. cerevisiae YRH396 deriving from S. cerevisiae YB-2625 increased cell growth when xylose was used as the sole carbon source, leading to 13.5 and 18.1%, respectively, more xylose consumption. CONCLUSIONS Enhanced oxidative stress tolerance and relief of glucose repression are proposed to be two major mechanisms for superior xylose utilization by S. cerevisiae YB-2625. The present study provides insights into the innate regulatory mechanisms underlying xylose utilization in wild-type S. cerevisiae, which benefits the rapid development of robust yeast strains for lignocellulosic biorefineries.
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Affiliation(s)
- Cheng Cheng
- School of Life Science and Biotechnology, Dalian University of Technology, Dalian, 116024 China
| | - Rui-Qi Tang
- State Key Laboratory of Microbial Metabolism, School of Life Sciences and Biotechnology, Shanghai Jiao Tong University, Shanghai, 200240 China
| | - Liang Xiong
- School of Life Science and Biotechnology, Dalian University of Technology, Dalian, 116024 China
| | - Ronald E. Hector
- Bioenergy Research Unit, National Center for Agricultural Utilization Research, USDA-ARS, Peoria, IL USA
| | - Feng-Wu Bai
- State Key Laboratory of Microbial Metabolism, School of Life Sciences and Biotechnology, Shanghai Jiao Tong University, Shanghai, 200240 China
| | - Xin-Qing Zhao
- State Key Laboratory of Microbial Metabolism, School of Life Sciences and Biotechnology, Shanghai Jiao Tong University, Shanghai, 200240 China
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81
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Mao Y, Li G, Chang Z, Tao R, Cui Z, Wang Z, Tang YJ, Chen T, Zhao X. Metabolic engineering of Corynebacterium glutamicum for efficient production of succinate from lignocellulosic hydrolysate. BIOTECHNOLOGY FOR BIOFUELS 2018; 11:95. [PMID: 29636817 PMCID: PMC5883316 DOI: 10.1186/s13068-018-1094-z] [Citation(s) in RCA: 25] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/31/2017] [Accepted: 03/24/2018] [Indexed: 05/10/2023]
Abstract
BACKGROUND Succinate has been recognized as one of the most important bio-based building block chemicals due to its numerous potential applications. However, efficient methods for the production of succinate from lignocellulosic feedstock were rarely reported. Nevertheless, Corynebacterium glutamicum was engineered to efficiently produce succinate from glucose in our previous study. RESULTS In this work, C. glutamicum was engineered for efficient succinate production from lignocellulosic hydrolysate. First, xylose utilization of C. glutamicum was optimized by heterologous expression of xylA and xylB genes from different sources. Next, xylA and xylB from Xanthomonas campestris were selected among four candidates to accelerate xylose consumption and cell growth. Subsequently, the optimal xylA and xylB were co-expressed in C. glutamicum strain SAZ3 (ΔldhAΔptaΔpqoΔcatPsod-ppcPsod-pyc) along with genes encoding pyruvate carboxylase, citrate synthase, and a succinate exporter to achieve succinate production from xylose in a two-stage fermentation process. Xylose utilization and succinate production were further improved by overexpressing the endogenous tkt and tal genes and introducing araE from Bacillus subtilis. The final strain C. glutamicum CGS5 showed an excellent ability to produce succinate in two-stage fermentations by co-utilizing a glucose-xylose mixture under anaerobic conditions. A succinate titer of 98.6 g L-1 was produced from corn stalk hydrolysate with a yield of 0.87 g/g total substrates and a productivity of 4.29 g L-1 h-1 during the anaerobic stage. CONCLUSION This work introduces an efficient process for the bioconversion of biomass into succinate using a thoroughly engineered strain of C. glutamicum. To the best of our knowledge, this is the highest titer of succinate produced from non-food lignocellulosic feedstock, which highlights that the biosafety level 1 microorganism C. glutamicum is a promising platform for the envisioned lignocellulosic biorefinery.
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Affiliation(s)
- Yufeng Mao
- Key Laboratory of Systems Bioengineering (Ministry of Education), SynBio Research Platform, Collaborative Innovation Center of Chemical Science and Engineering (Tianjin), School of Chemical Engineering and Technology, Tianjin University, Tianjin, 300072 China
| | - Guiying Li
- Key Laboratory of Systems Bioengineering (Ministry of Education), SynBio Research Platform, Collaborative Innovation Center of Chemical Science and Engineering (Tianjin), School of Chemical Engineering and Technology, Tianjin University, Tianjin, 300072 China
| | - Zhishuai Chang
- Key Laboratory of Systems Bioengineering (Ministry of Education), SynBio Research Platform, Collaborative Innovation Center of Chemical Science and Engineering (Tianjin), School of Chemical Engineering and Technology, Tianjin University, Tianjin, 300072 China
| | - Ran Tao
- Key Laboratory of Systems Bioengineering (Ministry of Education), SynBio Research Platform, Collaborative Innovation Center of Chemical Science and Engineering (Tianjin), School of Chemical Engineering and Technology, Tianjin University, Tianjin, 300072 China
| | - Zhenzhen Cui
- Key Laboratory of Systems Bioengineering (Ministry of Education), SynBio Research Platform, Collaborative Innovation Center of Chemical Science and Engineering (Tianjin), School of Chemical Engineering and Technology, Tianjin University, Tianjin, 300072 China
| | - Zhiwen Wang
- Key Laboratory of Systems Bioengineering (Ministry of Education), SynBio Research Platform, Collaborative Innovation Center of Chemical Science and Engineering (Tianjin), School of Chemical Engineering and Technology, Tianjin University, Tianjin, 300072 China
| | - Ya-jie Tang
- Key Laboratory of Fermentation Engineering, Ministry of Education, Hubei University of Technology, Wuhan, 430068 China
| | - Tao Chen
- Key Laboratory of Systems Bioengineering (Ministry of Education), SynBio Research Platform, Collaborative Innovation Center of Chemical Science and Engineering (Tianjin), School of Chemical Engineering and Technology, Tianjin University, Tianjin, 300072 China
| | - Xueming Zhao
- Key Laboratory of Systems Bioengineering (Ministry of Education), SynBio Research Platform, Collaborative Innovation Center of Chemical Science and Engineering (Tianjin), School of Chemical Engineering and Technology, Tianjin University, Tianjin, 300072 China
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82
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Tran Nguyen Hoang P, Ko JK, Gong G, Um Y, Lee SM. Genomic and phenotypic characterization of a refactored xylose-utilizing Saccharomyces cerevisiae strain for lignocellulosic biofuel production. BIOTECHNOLOGY FOR BIOFUELS 2018; 11:268. [PMID: 30288173 PMCID: PMC6162923 DOI: 10.1186/s13068-018-1269-7] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/02/2018] [Accepted: 09/21/2018] [Indexed: 05/12/2023]
Abstract
BACKGROUND Engineered strains of Saccharomyces cerevisiae have significantly improved the prospects of biorefinery by improving the bioconversion yields in lignocellulosic bioethanol production and expanding the product profiles to include advanced biofuels and chemicals. However, the lignocellulosic biorefinery concept has not been fully applied using engineered strains in which either xylose utilization or advanced biofuel/chemical production pathways have been upgraded separately. Specifically, high-performance xylose-fermenting strains have rarely been employed as advanced biofuel and chemical production platforms and require further engineering to expand their product profiles. RESULTS In this study, we refactored a high-performance xylose-fermenting S. cerevisiae that could potentially serve as a platform strain for advanced biofuels and biochemical production. Through combinatorial CRISPR-Cas9-mediated rational and evolutionary engineering, we obtained a newly refactored isomerase-based xylose-fermenting strain, XUSE, that demonstrated efficient conversion of xylose into ethanol with a high yield of 0.43 g/g. In addition, XUSE exhibited the simultaneous fermentation of glucose and xylose with negligible glucose inhibition, indicating the potential of this isomerase-based xylose-utilizing strain for lignocellulosic biorefinery. The genomic and transcriptomic analysis of XUSE revealed beneficial mutations and changes in gene expression that are responsible for the enhanced xylose fermentation performance of XUSE. CONCLUSIONS In this study, we developed a high-performance xylose-fermenting S. cerevisiae strain, XUSE, with high ethanol yield and negligible glucose inhibition. Understanding the genomic and transcriptomic characteristics of XUSE revealed isomerase-based engineering strategies for improved xylose fermentation in S. cerevisiae. With high xylose fermentation performance and room for further engineering, XUSE could serve as a promising platform strain for lignocellulosic biorefinery.
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Affiliation(s)
- Phuong Tran Nguyen Hoang
- Clean Energy Research Center, Korea Institute of Science and Technology (KIST), Seoul, 02792 Republic of Korea
- Division of Energy and Environment Technology, University of Science and Technology (UST), Daejeon, 34113 Republic of Korea
| | - Ja Kyong Ko
- Clean Energy Research Center, Korea Institute of Science and Technology (KIST), Seoul, 02792 Republic of Korea
| | - Gyeongtaek Gong
- Clean Energy Research Center, Korea Institute of Science and Technology (KIST), Seoul, 02792 Republic of Korea
| | - Youngsoon Um
- Clean Energy Research Center, Korea Institute of Science and Technology (KIST), Seoul, 02792 Republic of Korea
- Division of Energy and Environment Technology, University of Science and Technology (UST), Daejeon, 34113 Republic of Korea
| | - Sun-Mi Lee
- Clean Energy Research Center, Korea Institute of Science and Technology (KIST), Seoul, 02792 Republic of Korea
- Division of Energy and Environment Technology, University of Science and Technology (UST), Daejeon, 34113 Republic of Korea
- Green School, Korea University, Seoul, 02841 Republic of Korea
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83
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Jin YS, Cate JHD. Metabolic engineering of yeast for lignocellulosic biofuel production. Curr Opin Chem Biol 2017; 41:99-106. [DOI: 10.1016/j.cbpa.2017.10.025] [Citation(s) in RCA: 31] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2017] [Revised: 10/16/2017] [Accepted: 10/20/2017] [Indexed: 01/04/2023]
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84
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Lee M, Rozeboom HJ, de Waal PP, de Jong RM, Dudek HM, Janssen DB. Metal Dependence of the Xylose Isomerase from Piromyces sp. E2 Explored by Activity Profiling and Protein Crystallography. Biochemistry 2017; 56:5991-6005. [PMID: 29045784 PMCID: PMC5688467 DOI: 10.1021/acs.biochem.7b00777] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Abstract
Xylose isomerase from Piromyces sp. E2 (PirXI) can be used to equip Saccharomyces cerevisiae with the capacity to ferment xylose to ethanol. The biochemical properties and structure of the enzyme have not been described even though its metal content, catalytic parameters, and expression level are critical for rapid xylose utilization. We have isolated the enzyme after high-level expression in Escherichia coli, analyzed the metal dependence of its catalytic properties, and determined 12 crystal structures in the presence of different metals, substrates, and substrate analogues. The activity assays revealed that various bivalent metals can activate PirXI for xylose isomerization. Among these metals, Mn2+ is the most favorable for catalytic activity. Furthermore, the enzyme shows the highest affinity for Mn2+, which was established by measuring the activation constants (Kact) for different metals. Metal analysis of the purified enzyme showed that in vivo the enzyme binds a mixture of metals that is determined by metal availability as well as affinity, indicating that the native metal composition can influence activity. The crystal structures show the presence of an active site similar to that of other xylose isomerases, with a d-xylose binding site containing two tryptophans and a catalytic histidine, as well as two metal binding sites that are formed by carboxylate groups of conserved aspartates and glutamates. The binding positions and conformations of the metal-coordinating residues varied slightly for different metals, which is hypothesized to contribute to the observed metal dependence of the isomerase activity.
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Affiliation(s)
- Misun Lee
- Biochemical Laboratory, Groningen Biomolecular Sciences and Biotechnology Institute, University of Groningen , Nijenborgh 4, 9747 AG Groningen, The Netherlands
| | - Henriëtte J Rozeboom
- Biochemical Laboratory, Groningen Biomolecular Sciences and Biotechnology Institute, University of Groningen , Nijenborgh 4, 9747 AG Groningen, The Netherlands
| | - Paul P de Waal
- DSM Biotechnology Center , Alexander Fleminglaan 1, 2613 AX Delft, The Netherlands
| | - Rene M de Jong
- DSM Biotechnology Center , Alexander Fleminglaan 1, 2613 AX Delft, The Netherlands
| | - Hanna M Dudek
- Biochemical Laboratory, Groningen Biomolecular Sciences and Biotechnology Institute, University of Groningen , Nijenborgh 4, 9747 AG Groningen, The Netherlands
| | - Dick B Janssen
- Biochemical Laboratory, Groningen Biomolecular Sciences and Biotechnology Institute, University of Groningen , Nijenborgh 4, 9747 AG Groningen, The Netherlands
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85
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Seppälä S, Wilken SE, Knop D, Solomon KV, O’Malley MA. The importance of sourcing enzymes from non-conventional fungi for metabolic engineering and biomass breakdown. Metab Eng 2017; 44:45-59. [DOI: 10.1016/j.ymben.2017.09.008] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/13/2017] [Revised: 09/16/2017] [Accepted: 09/16/2017] [Indexed: 10/18/2022]
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86
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Transcriptome changes in adaptive evolution of xylose-fermenting industrial Saccharomyces cerevisiae strains with δ-integration of different xylA genes. Appl Microbiol Biotechnol 2017; 101:7741-7753. [DOI: 10.1007/s00253-017-8494-z] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/24/2017] [Revised: 08/01/2017] [Accepted: 08/03/2017] [Indexed: 12/23/2022]
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87
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Jansen MLA, Bracher JM, Papapetridis I, Verhoeven MD, de Bruijn H, de Waal PP, van Maris AJA, Klaassen P, Pronk JT. Saccharomyces cerevisiae strains for second-generation ethanol production: from academic exploration to industrial implementation. FEMS Yeast Res 2017; 17:3868933. [PMID: 28899031 PMCID: PMC5812533 DOI: 10.1093/femsyr/fox044] [Citation(s) in RCA: 98] [Impact Index Per Article: 14.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/13/2017] [Accepted: 06/15/2017] [Indexed: 11/18/2022] Open
Abstract
The recent start-up of several full-scale 'second generation' ethanol plants marks a major milestone in the development of Saccharomyces cerevisiae strains for fermentation of lignocellulosic hydrolysates of agricultural residues and energy crops. After a discussion of the challenges that these novel industrial contexts impose on yeast strains, this minireview describes key metabolic engineering strategies that have been developed to address these challenges. Additionally, it outlines how proof-of-concept studies, often developed in academic settings, can be used for the development of robust strain platforms that meet the requirements for industrial application. Fermentation performance of current engineered industrial S. cerevisiae strains is no longer a bottleneck in efforts to achieve the projected outputs of the first large-scale second-generation ethanol plants. Academic and industrial yeast research will continue to strengthen the economic value position of second-generation ethanol production by further improving fermentation kinetics, product yield and cellular robustness under process conditions.
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Affiliation(s)
- Mickel L. A. Jansen
- DSM Biotechnology Centre, Alexander Fleminglaan 1, 2613 AX Delft, The
Netherlands
| | - Jasmine M. Bracher
- Department of Biotechnology, Delft University of Technology, Van der Maasweg
9, 2629 HZ Delft, The Netherlands
| | - Ioannis Papapetridis
- Department of Biotechnology, Delft University of Technology, Van der Maasweg
9, 2629 HZ Delft, The Netherlands
| | - Maarten D. Verhoeven
- Department of Biotechnology, Delft University of Technology, Van der Maasweg
9, 2629 HZ Delft, The Netherlands
| | - Hans de Bruijn
- DSM Biotechnology Centre, Alexander Fleminglaan 1, 2613 AX Delft, The
Netherlands
| | - Paul P. de Waal
- DSM Biotechnology Centre, Alexander Fleminglaan 1, 2613 AX Delft, The
Netherlands
| | - Antonius J. A. van Maris
- Department of Biotechnology, Delft University of Technology, Van der Maasweg
9, 2629 HZ Delft, The Netherlands
| | - Paul Klaassen
- 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
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88
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Liu J, Ma Z, Zhu H, Caiyin Q, Liang D, Wu H, Huang X, Qiao J. Improving xylose utilization of defatted rice bran for nisin production by overexpression of a xylose transcriptional regulator in Lactococcus lactis. BIORESOURCE TECHNOLOGY 2017; 238:690-697. [PMID: 28499254 DOI: 10.1016/j.biortech.2017.04.076] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/07/2017] [Revised: 04/18/2017] [Accepted: 04/19/2017] [Indexed: 06/07/2023]
Abstract
Present investigation explores the potential of defatted rice bran (DRB) serving as sole carbon source and partial nitrogen source to support Lactococcus lactis growth and nisin production. To retain the nutrients in DRB, especially protein fractions, thermal pretreatment followed by enzymatic hydrolysis without washing step was applied for saccharification. A maximum of 45.64g reducing sugar mainly containing 30.26g glucose and 5.66g xylose from 100g DRB was attained in hydrolysates of DRB (HD). A novel strategy of xylR (xylose transcriptional regulator) overexpression followed by evolutionary engineering was proposed, which significantly increased the capacity of L. lactis to metabolize xylose. Subsequently, RT-PCR results indicated that xylR overexpression stimulated expression of xylose assimilation genes synergistically with exposure to xylose. In HD medium, the highest nisin titer of the engineered strain FEXR was 3824.53IU/mL, which was 1.37 times of that in sucrose medium by the original strain F44.
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Affiliation(s)
- Jiaheng Liu
- Key Laboratory of Systems Bioengineering, Ministry of Education (Tianjin University), Tianjin 300072, China; School of Chemical Engineering and Technology, Tianjin University, Tianjin 300072, China; Collaborative Innovation Center of Chemical Science and Engineering (Tianjin), Tianjin 300072, China
| | - Zelin Ma
- Key Laboratory of Systems Bioengineering, Ministry of Education (Tianjin University), Tianjin 300072, China; School of Chemical Engineering and Technology, Tianjin University, Tianjin 300072, China; Collaborative Innovation Center of Chemical Science and Engineering (Tianjin), Tianjin 300072, China
| | - Hongji Zhu
- Key Laboratory of Systems Bioengineering, Ministry of Education (Tianjin University), Tianjin 300072, China; School of Chemical Engineering and Technology, Tianjin University, Tianjin 300072, China
| | - Qinggele Caiyin
- Key Laboratory of Systems Bioengineering, Ministry of Education (Tianjin University), Tianjin 300072, China; School of Chemical Engineering and Technology, Tianjin University, Tianjin 300072, China
| | - Dongmei Liang
- Key Laboratory of Systems Bioengineering, Ministry of Education (Tianjin University), Tianjin 300072, China; School of Chemical Engineering and Technology, Tianjin University, Tianjin 300072, China; Collaborative Innovation Center of Chemical Science and Engineering (Tianjin), Tianjin 300072, China
| | - Hao Wu
- Key Laboratory of Systems Bioengineering, Ministry of Education (Tianjin University), Tianjin 300072, China; School of Chemical Engineering and Technology, Tianjin University, Tianjin 300072, China; Collaborative Innovation Center of Chemical Science and Engineering (Tianjin), Tianjin 300072, China
| | - Xu Huang
- China Oil & Foodstuffs Corporation (COFCO), Nutrition and Health Research Institute, China
| | - Jianjun Qiao
- Key Laboratory of Systems Bioengineering, Ministry of Education (Tianjin University), Tianjin 300072, China; School of Chemical Engineering and Technology, Tianjin University, Tianjin 300072, China; Collaborative Innovation Center of Chemical Science and Engineering (Tianjin), Tianjin 300072, China.
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89
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Hou J, Qiu C, Shen Y, Li H, Bao X. Engineering of Saccharomyces cerevisiae for the efficient co-utilization of glucose and xylose. FEMS Yeast Res 2017; 17:3861258. [DOI: 10.1093/femsyr/fox034] [Citation(s) in RCA: 57] [Impact Index Per Article: 8.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2017] [Accepted: 06/02/2017] [Indexed: 11/14/2022] Open
Affiliation(s)
- Jin Hou
- State Key Laboratory of Microbial Technology, The School of Life Science, Shandong University, Jinan, 250100, China
| | - Chenxi Qiu
- State Key Laboratory of Microbial Technology, The School of Life Science, Shandong University, Jinan, 250100, China
| | - Yu Shen
- State Key Laboratory of Microbial Technology, The School of Life Science, Shandong University, Jinan, 250100, China
| | - Hongxing Li
- State Key Laboratory of Microbial Technology, The School of Life Science, Shandong University, Jinan, 250100, China
- Shandong Provincial Key Laboratory of Microbial Engineering, Qi Lu University of Technology, Jinan, 250353, China
| | - Xiaoming Bao
- State Key Laboratory of Microbial Technology, The School of Life Science, Shandong University, Jinan, 250100, China
- Shandong Provincial Key Laboratory of Microbial Engineering, Qi Lu University of Technology, Jinan, 250353, China
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90
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Hope EA, Amorosi CJ, Miller AW, Dang K, Heil CS, Dunham MJ. Experimental Evolution Reveals Favored Adaptive Routes to Cell Aggregation in Yeast. Genetics 2017; 206:1153-1167. [PMID: 28450459 PMCID: PMC5499169 DOI: 10.1534/genetics.116.198895] [Citation(s) in RCA: 52] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/05/2016] [Accepted: 04/06/2017] [Indexed: 02/02/2023] Open
Abstract
Yeast flocculation is a community-building cell aggregation trait that is an important mechanism of stress resistance and a useful phenotype for brewers; however, it is also a nuisance in many industrial processes, in clinical settings, and in the laboratory. Chemostat-based evolution experiments are impaired by inadvertent selection for aggregation, which we observe in 35% of populations. These populations provide a testing ground for understanding the breadth of genetic mechanisms Saccharomyces cerevisiae uses to flocculate, and which of those mechanisms provide the biggest adaptive advantages. In this study, we employed experimental evolution as a tool to ask whether one or many routes to flocculation are favored, and to engineer a strain with reduced flocculation potential. Using a combination of whole genome sequencing and bulk segregant analysis, we identified causal mutations in 23 independent clones that had evolved cell aggregation during hundreds of generations of chemostat growth. In 12 of those clones, we identified a transposable element insertion in the promoter region of known flocculation gene FLO1, and, in an additional five clones, we recovered loss-of-function mutations in transcriptional repressor TUP1, which regulates FLO1 and other related genes. Other causal mutations were found in genes that have not been previously connected to flocculation. Evolving a flo1 deletion strain revealed that this single deletion reduces flocculation occurrences to 3%, and demonstrated the efficacy of using experimental evolution as a tool to identify and eliminate the primary adaptive routes for undesirable traits.
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Affiliation(s)
- Elyse A Hope
- Department of Genome Sciences, University of Washington School of Medicine, Seattle, Washington 98195
| | - Clara J Amorosi
- Department of Genome Sciences, University of Washington School of Medicine, Seattle, Washington 98195
| | - Aaron W Miller
- Department of Genome Sciences, University of Washington School of Medicine, Seattle, Washington 98195
| | - Kolena Dang
- Department of Genome Sciences, University of Washington School of Medicine, Seattle, Washington 98195
| | - Caiti Smukowski Heil
- Department of Genome Sciences, University of Washington School of Medicine, Seattle, Washington 98195
| | - Maitreya J Dunham
- Department of Genome Sciences, University of Washington School of Medicine, Seattle, Washington 98195
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91
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Deparis Q, Claes A, Foulquié-Moreno MR, Thevelein JM. Engineering tolerance to industrially relevant stress factors in yeast cell factories. FEMS Yeast Res 2017; 17:3861662. [PMID: 28586408 PMCID: PMC5812522 DOI: 10.1093/femsyr/fox036] [Citation(s) in RCA: 107] [Impact Index Per Article: 15.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2017] [Accepted: 06/04/2017] [Indexed: 01/01/2023] Open
Abstract
The main focus in development of yeast cell factories has generally been on establishing optimal activity of heterologous pathways and further metabolic engineering of the host strain to maximize product yield and titer. Adequate stress tolerance of the host strain has turned out to be another major challenge for obtaining economically viable performance in industrial production. Although general robustness is a universal requirement for industrial microorganisms, production of novel compounds using artificial metabolic pathways presents additional challenges. Many of the bio-based compounds desirable for production by cell factories are highly toxic to the host cells in the titers required for economic viability. Artificial metabolic pathways also turn out to be much more sensitive to stress factors than endogenous pathways, likely because regulation of the latter has been optimized in evolution in myriads of environmental conditions. We discuss different environmental and metabolic stress factors with high relevance for industrial utilization of yeast cell factories and the experimental approaches used to engineer higher stress tolerance. Improving stress tolerance in a predictable manner in yeast cell factories should facilitate their widespread utilization in the bio-based economy and extend the range of products successfully produced in large scale in a sustainable and economically profitable way.
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Affiliation(s)
- Quinten Deparis
- Laboratory of Molecular Cell Biology, Institute of Botany and Microbiology, B-3001 KU Leuven, Belgium
- Center for Microbiology, VIB, Kasteelpark Arenberg 31, B-3001 Leuven-Heverlee, Flanders, Belgium
| | - Arne Claes
- Laboratory of Molecular Cell Biology, Institute of Botany and Microbiology, B-3001 KU Leuven, Belgium
- Center for Microbiology, VIB, Kasteelpark Arenberg 31, B-3001 Leuven-Heverlee, Flanders, Belgium
| | - Maria R. Foulquié-Moreno
- Laboratory of Molecular Cell Biology, Institute of Botany and Microbiology, B-3001 KU Leuven, Belgium
- Center for Microbiology, VIB, Kasteelpark Arenberg 31, B-3001 Leuven-Heverlee, Flanders, Belgium
| | - Johan M. Thevelein
- Laboratory of Molecular Cell Biology, Institute of Botany and Microbiology, B-3001 KU Leuven, Belgium
- Center for Microbiology, VIB, Kasteelpark Arenberg 31, B-3001 Leuven-Heverlee, Flanders, Belgium
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92
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Kwak S, Jin YS. Production of fuels and chemicals from xylose by engineered Saccharomyces cerevisiae: a review and perspective. Microb Cell Fact 2017; 16:82. [PMID: 28494761 PMCID: PMC5425999 DOI: 10.1186/s12934-017-0694-9] [Citation(s) in RCA: 141] [Impact Index Per Article: 20.1] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/25/2016] [Accepted: 05/02/2017] [Indexed: 02/06/2023] Open
Abstract
Efficient xylose utilization is one of the most important pre-requisites for developing an economic microbial conversion process of terrestrial lignocellulosic biomass into biofuels and biochemicals. A robust ethanol producing yeast Saccharomyces cerevisiae has been engineered with heterologous xylose assimilation pathways. A two-step oxidoreductase pathway consisting of NAD(P)H-linked xylose reductase and NAD+-linked xylitol dehydrogenase, and one-step isomerase pathway using xylose isomerase have been employed to enable xylose assimilation in engineered S. cerevisiae. However, the resulting engineered yeast exhibited inefficient and slow xylose fermentation. In order to improve the yield and productivity of xylose fermentation, expression levels of xylose assimilation pathway enzymes and their kinetic properties have been optimized, and additional optimizations of endogenous or heterologous metabolisms have been achieved. These efforts have led to the development of engineered yeast strains ready for the commercialization of cellulosic bioethanol. Interestingly, xylose metabolism by engineered yeast was preferably respiratory rather than fermentative as in glucose metabolism, suggesting that xylose can serve as a desirable carbon source capable of bypassing metabolic barriers exerted by glucose repression. Accordingly, engineered yeasts showed superior production of valuable metabolites derived from cytosolic acetyl-CoA and pyruvate, such as 1-hexadecanol and lactic acid, when the xylose assimilation pathway and target synthetic pathways were optimized in an adequate manner. While xylose has been regarded as a sugar to be utilized because it is present in cellulosic hydrolysates, potential benefits of using xylose instead of glucose for yeast-based biotechnological processes need to be realized.
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Affiliation(s)
- Suryang Kwak
- Department of Food Science and Human Nutrition and Carl R. Woose Institute for Genomic Biology, University of Illinois at Urbana-Champaign, Urbana, IL, USA
| | - Yong-Su Jin
- Department of Food Science and Human Nutrition and Carl R. Woose Institute for Genomic Biology, University of Illinois at Urbana-Champaign, Urbana, IL, USA.
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93
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Verhoeven MD, Lee M, Kamoen L, van den Broek M, Janssen DB, Daran JMG, van Maris AJA, Pronk JT. Mutations in PMR1 stimulate xylose isomerase activity and anaerobic growth on xylose of engineered Saccharomyces cerevisiae by influencing manganese homeostasis. Sci Rep 2017; 7:46155. [PMID: 28401919 PMCID: PMC5388867 DOI: 10.1038/srep46155] [Citation(s) in RCA: 47] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2016] [Accepted: 03/09/2017] [Indexed: 01/04/2023] Open
Abstract
Combined overexpression of xylulokinase, pentose-phosphate-pathway enzymes and a heterologous xylose isomerase (XI) is required but insufficient for anaerobic growth of Saccharomyces cerevisiae on d-xylose. Single-step Cas9-assisted implementation of these modifications yielded a yeast strain expressing Piromyces XI that showed fast aerobic growth on d-xylose. However, anaerobic growth required a 12-day adaptation period. Xylose-adapted cultures carried mutations in PMR1, encoding a Golgi Ca2+/Mn2+ ATPase. Deleting PMR1 in the parental XI-expressing strain enabled instantaneous anaerobic growth on d-xylose. In pmr1 strains, intracellular Mn2+ concentrations were much higher than in the parental strain. XI activity assays in cell extracts and reconstitution experiments with purified XI apoenzyme showed superior enzyme kinetics with Mn2+ relative to other divalent metal ions. This study indicates engineering of metal homeostasis as a relevant approach for optimization of metabolic pathways involving metal-dependent enzymes. Specifically, it identifies metal interactions of heterologous XIs as an underexplored aspect of engineering xylose metabolism in yeast.
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Affiliation(s)
- Maarten D Verhoeven
- Department of Biotechnology, Delft University of Technology, Van der Maasweg 9, 2629 HZ Delft, The Netherlands
| | - Misun Lee
- Department of Biochemistry, Groningen Biomolecular Sciences and Biotechnology Institute (GBB), University of Groningen, Nijenborgh 4, 9747 AG Groningen, The Netherlands
| | - Lycka Kamoen
- 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
| | - Dick B Janssen
- Department of Biochemistry, Groningen Biomolecular Sciences and Biotechnology Institute (GBB), University of Groningen, Nijenborgh 4, 9747 AG Groningen, The Netherlands
| | - Jean-Marc G Daran
- Department of Biotechnology, Delft University of Technology, Van der Maasweg 9, 2629 HZ Delft, The Netherlands
| | - Antonius J A van Maris
- 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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94
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Construction, characterization and application of a genome-wide promoter library in Saccharomyces cerevisiae. Front Chem Sci Eng 2017. [DOI: 10.1007/s11705-017-1621-7] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
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95
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Direct bioethanol production from wheat straw using xylose/glucose co-fermentation by co-culture of two recombinant yeasts. ACTA ACUST UNITED AC 2017; 44:453-464. [DOI: 10.1007/s10295-016-1893-9] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/08/2016] [Accepted: 12/22/2016] [Indexed: 10/20/2022]
Abstract
Abstract
To achieve a cost-effective bioconversion of lignocellulosic materials, a novel xylose/glucose co-fermentation process by co-culture of cellulose-utilizing recombinant Saccharomyces cerevisiae (S. cerevisiae) and xylan-utilizing recombinant Pichia pastoris (P. pastoris) was developed, in which ethanol was produced directly from wheat straw without additional hydrolytic enzymes. Recombinant S. cerevisiae coexpressing three types of cellulase and recombinant P. pastoris coexpressing two types of xylanase were constructed, respectively. All cellulases and xylanases were successfully expressed and similar extracellular activity was demonstrated. The maximum ethanol concentration of 32.6 g L−1 with the yield 0.42 g g−1 was achieved from wheat straw corresponding to 100 g L−1 of total sugar after 80 h co-fermentation, which corresponds to 82.6% of the theoretical yield. These results demonstrate that the direct and efficient ethanol production from lignocellulosic materials is accomplished by simultaneous saccharification (cellulose and hemicellulose) and co-fermentation (glucose and xylose) with the co-culture of the two recombinant yeasts.
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96
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Metabolic engineering of a haploid strain derived from a triploid industrial yeast for producing cellulosic ethanol. Metab Eng 2017; 40:176-185. [DOI: 10.1016/j.ymben.2017.02.006] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/28/2016] [Revised: 02/06/2017] [Accepted: 02/14/2017] [Indexed: 12/25/2022]
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97
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Xia PF, Zhang GC, Walker B, Seo SO, Kwak S, Liu JJ, Kim H, Ort DR, Wang SG, Jin YS. Recycling Carbon Dioxide during Xylose Fermentation by Engineered Saccharomyces cerevisiae. ACS Synth Biol 2017; 6:276-283. [PMID: 27744692 DOI: 10.1021/acssynbio.6b00167] [Citation(s) in RCA: 42] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Global climate change caused by the emission of anthropogenic greenhouse gases (GHGs) is a grand challenge to humanity. To alleviate the trend, the consumption of fossil fuels needs to be largely reduced and alternative energy technologies capable of controlling GHG emissions are anticipated. In this study, we introduced a synthetic reductive pentose phosphate pathway (rPPP) into a xylose-fermenting Saccharomyces cerevisiae strain SR8 to achieve simultaneous lignocellulosic bioethanol production and carbon dioxide recycling. Specifically, ribulose-1,5-bisphosphate carboxylase/oxygenase from Rhodospirillum rubrum and phosphoribulokinase from Spinacia oleracea were introduced into the SR8 strain. The resulting strain with the synthetic rPPP was able to exhibit a higher yield of ethanol and lower yields of byproducts (xylitol and glycerol) than a control strain. In addition, the reduced release of carbon dioxide by the engineered strain was observed during xylose fermentation, suggesting that the carbon dioxide generated by pyruvate decarboxylase was partially reassimilated through the synthetic rPPP. These results demonstrated that recycling of carbon dioxide from the ethanol fermentation pathway in yeast can be achieved during lignocellulosic bioethanol production through a synthetic carbon conservative metabolic pathway. This strategy has a great potential to alleviate GHG emissions during the production of second-generation ethanol.
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Affiliation(s)
- Peng-Fei Xia
- School
of Environmental Science and Engineering, Shandong University, 27 Shanda Nanlu, Jinan 250100, People’s Republic of China
- Carl
R. Woese Institute for Genomic Biology, University of Illinois at Urbana−Champaign, 1206 West Gregory Drive, Urbana, Illinois 61801, United States
| | - Guo-Chang Zhang
- Department
of Food Science and Human Nutrition, University of Illinois at Urbana−Champaign, 905 South Goodwin Avenue, Urbana, Illinois 61801, United States
| | - Berkley Walker
- Carl
R. Woese Institute for Genomic Biology, University of Illinois at Urbana−Champaign, 1206 West Gregory Drive, Urbana, Illinois 61801, United States
- Photosynthetic
Research Unit, United States Department of Agriculture, Urbana Illinois 61801, United States
| | - Seung-Oh Seo
- Department
of Food Science and Human Nutrition, University of Illinois at Urbana−Champaign, 905 South Goodwin Avenue, Urbana, Illinois 61801, United States
| | - Suryang Kwak
- Carl
R. Woese Institute for Genomic Biology, University of Illinois at Urbana−Champaign, 1206 West Gregory Drive, Urbana, Illinois 61801, United States
- Department
of Food Science and Human Nutrition, University of Illinois at Urbana−Champaign, 905 South Goodwin Avenue, Urbana, Illinois 61801, United States
| | - Jing-Jing Liu
- Carl
R. Woese Institute for Genomic Biology, University of Illinois at Urbana−Champaign, 1206 West Gregory Drive, Urbana, Illinois 61801, United States
| | - Heejin Kim
- Carl
R. Woese Institute for Genomic Biology, University of Illinois at Urbana−Champaign, 1206 West Gregory Drive, Urbana, Illinois 61801, United States
- Department
of Food Science and Human Nutrition, University of Illinois at Urbana−Champaign, 905 South Goodwin Avenue, Urbana, Illinois 61801, United States
| | - Donald R. Ort
- Carl
R. Woese Institute for Genomic Biology, University of Illinois at Urbana−Champaign, 1206 West Gregory Drive, Urbana, Illinois 61801, United States
- Photosynthetic
Research Unit, United States Department of Agriculture, Urbana Illinois 61801, United States
- Department
of Plant Biology, University of Illinois at Urbana−Champaign, Urbana, Illinois 61801, United States
| | - Shu-Guang Wang
- School
of Environmental Science and Engineering, Shandong University, 27 Shanda Nanlu, Jinan 250100, People’s Republic of China
| | - Yong-Su Jin
- Carl
R. Woese Institute for Genomic Biology, University of Illinois at Urbana−Champaign, 1206 West Gregory Drive, Urbana, Illinois 61801, United States
- Department
of Food Science and Human Nutrition, University of Illinois at Urbana−Champaign, 905 South Goodwin Avenue, Urbana, Illinois 61801, United States
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98
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Goold HD, Kroukamp H, Williams TC, Paulsen IT, Varela C, Pretorius IS. Yeast's balancing act between ethanol and glycerol production in low-alcohol wines. Microb Biotechnol 2017; 10:264-278. [PMID: 28083938 PMCID: PMC5328816 DOI: 10.1111/1751-7915.12488] [Citation(s) in RCA: 91] [Impact Index Per Article: 13.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/09/2016] [Revised: 11/17/2016] [Accepted: 11/23/2016] [Indexed: 01/06/2023] Open
Abstract
Alcohol is fundamental to the character of wine, yet too much can put a wine off‐balance. A wine is regarded to be well balanced if its alcoholic strength, acidity, sweetness, fruitiness and tannin structure complement each other so that no single component dominates on the palate. Balancing a wine's positive fruit flavours with the optimal absolute and relative concentration of alcohol can be surprisingly difficult. Over the past three decades, consumers have increasingly demanded wine with richer and riper fruit flavour profiles. In response, grape and wine producers have extended harvest times to increase grape maturity and enhance the degree of fruit flavours and colour intensity. However, a higher degree of grape maturity results in increased grape sugar concentration, which in turn results in wines with elevated alcohol concentration. On average, the alcohol strength of red wines from many warm wine‐producing regions globally rose by about 2% (v/v) during this period. Notwithstanding that many of these ‘full‐bodied, fruit‐forward’ wines are well balanced and sought after, there is also a significant consumer market segment that seeks lighter styles with less ethanol‐derived ‘hotness’ on the palate. Consumer‐focussed wine producers are developing and implementing several strategies in the vineyard and winery to reduce the alcohol concentration in wines produced from well‐ripened grapes. In this context, Saccharomyces cerevisiae wine yeasts have proven to be a pivotal strategy to reduce ethanol formation during the fermentation of grape musts with high sugar content (> 240 g l−1). One of the approaches has been to develop ‘low‐alcohol’ yeast strains which work by redirecting their carbon metabolism away from ethanol production to other metabolites, such as glycerol. This article reviews the current challenges of producing glycerol at the expense of ethanol. It also casts new light on yeast strain development programmes which, bolstered by synthetic genomics, could potentially overcome these challenges.
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Affiliation(s)
- Hugh D Goold
- Department of Chemistry and Biomolecular Sciences, Macquarie University, Sydney, NSW, 2109, Australia.,New South Wales Department of Primary Industries, Locked Bag 21, Orange, NSW, 2800, Australia
| | - Heinrich Kroukamp
- Department of Chemistry and Biomolecular Sciences, Macquarie University, Sydney, NSW, 2109, Australia
| | - Thomas C Williams
- Department of Chemistry and Biomolecular Sciences, Macquarie University, Sydney, NSW, 2109, Australia
| | - Ian T Paulsen
- Department of Chemistry and Biomolecular Sciences, Macquarie University, Sydney, NSW, 2109, Australia
| | - Cristian Varela
- The Australian Wine Research Institute, PO Box 197, Adelaide, SA, 5064, Australia
| | - Isak S Pretorius
- Department of Chemistry and Biomolecular Sciences, Macquarie University, Sydney, NSW, 2109, Australia
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99
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Katahira S, Muramoto N, Moriya S, Nagura R, Tada N, Yasutani N, Ohkuma M, Onishi T, Tokuhiro K. Screening and evolution of a novel protist xylose isomerase from the termite Reticulitermes speratus for efficient xylose fermentation in Saccharomyces cerevisiae. BIOTECHNOLOGY FOR BIOFUELS 2017; 10:203. [PMID: 28852424 PMCID: PMC5569483 DOI: 10.1186/s13068-017-0890-1] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/20/2017] [Accepted: 08/16/2017] [Indexed: 05/12/2023]
Abstract
BACKGROUND The yeast Saccharomyces cerevisiae, a promising host for lignocellulosic bioethanol production, is unable to metabolize xylose. In attempts to confer xylose utilization ability in S. cerevisiae, a number of xylose isomerase (XI) genes have been expressed heterologously in this yeast. Although several of these XI encoding genes were functionally expressed in S. cerevisiae, the need still exists for a S. cerevisiae strain with improved xylose utilization ability for use in the commercial production of bioethanol. Although currently much effort has been devoted to achieve the objective, one of the solutions is to search for a new XI gene that would confer superior xylose utilization in S. cerevisiae. Here, we searched for novel XI genes from the protists residing in the hindgut of the termite Reticulitermes speratus. RESULTS Eight novel XI genes were obtained from a cDNA library, prepared from the protists of the R. speratus hindgut, by PCR amplification using degenerated primers based on highly conserved regions of amino acid sequences of different XIs. Phylogenetic analysis classified these cloned XIs into two groups, one showed relatively high similarities to Bacteroidetes and the other was comparatively similar to Firmicutes. The growth rate and the xylose consumption rate of the S. cerevisiae strain expressing the novel XI, which exhibited highest XI activity among the eight XIs, were superior to those exhibited by the strain expressing the XI gene from Piromyces sp. E2. Substitution of the asparagine residue at position 337 of the novel XI with a cysteine further improved the xylose utilization ability of the yeast strain. Interestingly, introducing point mutations in the corresponding asparagine residues in XIs originated from other organisms, such as Piromyces sp. E2 or Clostridium phytofermentans, similarly improved xylose utilization in S. cerevisiae. CONCLUSIONS A novel XI gene conferring superior xylose utilization in S. cerevisiae was successfully isolated from the protists in the termite hindgut. Isolation of this XI gene and identification of the point mutation described in this study might contribute to improving the productivity of industrial bioethanol.
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Affiliation(s)
- Satoshi Katahira
- Bioinspired Systems Research-Domain, Toyota Central R&D Labs., Inc., 41-1, Yokomichi, Nagakute, Aichi 480-1192 Japan
| | - Nobuhiko Muramoto
- Bioinspired Systems Research-Domain, Toyota Central R&D Labs., Inc., 41-1, Yokomichi, Nagakute, Aichi 480-1192 Japan
| | - Shigeharu Moriya
- RIKEN Center for Sustainable Resource Science, 1-7-22 Suehiro-cho, Tsurumi-ku, Yokohama, Kanagawa 230-0045 Japan
| | - Risa Nagura
- Bioinspired Systems Research-Domain, Toyota Central R&D Labs., Inc., 41-1, Yokomichi, Nagakute, Aichi 480-1192 Japan
| | - Nobuki Tada
- Biotechnology and Afforestation Laboratory, New Business Planning Div, Toyota Motor Corporation, 1099 Marune, Kurozasa-cho, Miyoshi, Aichi 470-0201 Japan
| | - Noriko Yasutani
- Biotechnology and Afforestation Laboratory, New Business Planning Div, Toyota Motor Corporation, 1099 Marune, Kurozasa-cho, Miyoshi, Aichi 470-0201 Japan
| | - Moriya Ohkuma
- RIKEN Center for Sustainable Resource Science, 3-1-1 Koyadai, Tsukuba, Ibaraki 305-0074 Japan
- Japan Collection of Microorganisms, RIKEN BioResource Center, 3-1-1 Koyadai, Tsukuba, Ibaraki 305-0074 Japan
| | - Toru Onishi
- Biotechnology and Afforestation Laboratory, New Business Planning Div, Toyota Motor Corporation, 1099 Marune, Kurozasa-cho, Miyoshi, Aichi 470-0201 Japan
| | - Kenro Tokuhiro
- Bioinspired Systems Research-Domain, Toyota Central R&D Labs., Inc., 41-1, Yokomichi, Nagakute, Aichi 480-1192 Japan
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100
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Zhang B, Zhu Y, Zhang J, Wang D, Sun L, Hong J. Engineered Kluyveromyces marxianus for pyruvate production at elevated temperature with simultaneous consumption of xylose and glucose. BIORESOURCE TECHNOLOGY 2017; 224:553-562. [PMID: 27955868 DOI: 10.1016/j.biortech.2016.11.110] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/09/2016] [Revised: 11/26/2016] [Accepted: 11/28/2016] [Indexed: 06/06/2023]
Abstract
Xylose and glucose from lignocellulose are sustainable sources for production of pyruvate, which is the starting material for the synthesis of many drugs and agrochemicals. In this study, the pyruvate decarboxylase gene (KmPDC1) and glycerol-3-phosphate dehydrogenase gene (KmGPD1) of Kluyveromyces marxianus YZJ051 were disrupted to prevent ethanol and glycerol accumulation. The deficient growth of PDC disruption was rescued by overexpressing mutant KmMTH1-ΔT. Then pentose phosphate pathway and xylitol dehydrogenase SsXYL2-ARS genes were overexpressed to obtain strain YZB053 which produced pyruvate with xylose other than glucose. It produced 24.62g/L pyruvate from 80g/L xylose with productivity of 0.51g/L/h at 42°C. Then, xylose-specific transporter ScGAL2-N376F was overexpressed to obtain strain YZB058, which simultaneously consumed 40g/L glucose and 20g/L xylose and produced 29.21g/L pyruvate with productivity of 0.81g/L/h at 42°C. Therefore, a platform for pyruvate production from glucose and xylose at elevated temperature was developed.
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Affiliation(s)
- Biao Zhang
- School of Life Sciences, University of Science and Technology of China, Hefei, Anhui 230027, PR China
| | - Yelin Zhu
- School of Life Sciences, University of Science and Technology of China, Hefei, Anhui 230027, PR China
| | - Jia Zhang
- Single-Cell Center, CAS Key Laboratory of Biofuels, Qingdao Institute of Bioenergy and Bioprocess Technology, Chinese Academy of Sciences, Qingdao, Shandong 266101, PR China
| | - Dongmei Wang
- School of Life Sciences, University of Science and Technology of China, Hefei, Anhui 230027, PR China
| | - Lianhong Sun
- School of Life Sciences, University of Science and Technology of China, Hefei, Anhui 230027, PR China
| | - Jiong Hong
- School of Life Sciences, University of Science and Technology of China, Hefei, Anhui 230027, PR China.
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