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Choi B, Tafur Rangel A, Kerkhoven EJ, Nygård Y. Engineering of Saccharomyces cerevisiae for enhanced metabolic robustness and L-lactic acid production from lignocellulosic biomass. Metab Eng 2024; 84:23-33. [PMID: 38788894 DOI: 10.1016/j.ymben.2024.05.003] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/16/2024] [Revised: 04/19/2024] [Accepted: 05/20/2024] [Indexed: 05/26/2024]
Abstract
Metabolic engineering for high productivity and increased robustness is needed to enable sustainable biomanufacturing of lactic acid from lignocellulosic biomass. Lactic acid is an important commodity chemical used for instance as a monomer for production of polylactic acid, a biodegradable polymer. Here, rational and model-based optimization was used to engineer a diploid, xylose fermenting Saccharomyces cerevisiae strain to produce L-lactic acid. The metabolic flux was steered towards lactic acid through the introduction of multiple lactate dehydrogenase encoding genes while deleting ERF2, GPD1, and CYB2. A production of 93 g/L of lactic acid with a yield of 0.84 g/g was achieved using xylose as the carbon source. To increase xylose utilization and reduce acetic acid synthesis, PHO13 and ALD6 were also deleted from the strain. Finally, CDC19 encoding a pyruvate kinase was overexpressed, resulting in a yield of 0.75 g lactic acid/g sugars consumed, when the substrate used was a synthetic lignocellulosic hydrolysate medium, containing hexoses, pentoses and inhibitors such as acetate and furfural. Notably, modeling also provided leads for understanding the influence of oxygen in lactic acid production. High lactic acid production from xylose, at oxygen-limitation could be explained by a reduced flux through the oxidative phosphorylation pathway. On the contrast, higher oxygen levels were beneficial for lactic acid production with the synthetic hydrolysate medium, likely as higher ATP concentrations are needed for tolerating the inhibitors therein. The work highlights the potential of S. cerevisiae for industrial production of lactic acid from lignocellulosic biomass.
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Affiliation(s)
- Bohyun Choi
- Department of Life Sciences, Industrial Biotechnology, Chalmers University of Technology, Gothenburg, Sweden
| | - Albert Tafur Rangel
- Department of Life Sciences, Systems and Synthetic Biology, Chalmers University of Technology, Gothenburg, Sweden; Novo Nordisk Foundation Center for Biosustainability, Technical University of Denmark, Kgs. Lyngby, Denmark
| | - Eduard J Kerkhoven
- Department of Life Sciences, Systems and Synthetic Biology, Chalmers University of Technology, Gothenburg, Sweden; Novo Nordisk Foundation Center for Biosustainability, Technical University of Denmark, Kgs. Lyngby, Denmark; SciLifeLab, Chalmers University of Technology, Gothenburg, Sweden
| | - Yvonne Nygård
- Department of Life Sciences, Industrial Biotechnology, Chalmers University of Technology, Gothenburg, Sweden; VTT Technical Research Centre of Finland Ltd, Espoo, Finland.
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2
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Ma XY, Coleman B, Prabhu P, Wen F. Segmentation and evaluation of pathway module efficiency: Quantitative approach to monitor and overcome evolving bottlenecks in xylose to ethanol pathway. BIORESOURCE TECHNOLOGY 2024; 395:130377. [PMID: 38278451 DOI: 10.1016/j.biortech.2024.130377] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/05/2023] [Revised: 01/15/2024] [Accepted: 01/22/2024] [Indexed: 01/28/2024]
Abstract
Engineering microbes that can efficiently ferment xylose to ethanol is critical to the development of renewable fuels from lignocellulosic biomass. To accelerate the strain optimization process, a method termed Segmentation and Evaluation of Pathway Module Efficiency (SEPME) was developed to enable rapid and iterative identification and removal of metabolic bottlenecks. Using SEPME, the overall pathway was segmented into two modules: the upstream xylose assimilation pathway and the downstream pentose phosphate pathway, glycolysis, and fermentation. The efficiencies of both modules were then quantified to identify the rate controlling module, followed by analyses of control coefficients, reaction rates, and byproduct concentrations to narrow down targets within the module. SEPME analysis revealed that as the strain was engineered with increasing xylose-to-ethanol yields, the bottlenecks shifted within a module and across the two modules. Guided by SEPME, these bottlenecks were removed one by one, and a strain approaching the theoretical ethanol yield was obtained.
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Affiliation(s)
- Xiao Yin Ma
- Department of Chemical Engineering, University of Michigan, Ann Arbor, MI 48109, United States; Catalysis Science and Technology Institute, University of Michigan, Ann Arbor, MI 48109, United States
| | - Bryan Coleman
- Department of Chemical Engineering, University of Michigan, Ann Arbor, MI 48109, United States; Catalysis Science and Technology Institute, University of Michigan, Ann Arbor, MI 48109, United States
| | - Ponnandy Prabhu
- Department of Chemical Engineering, University of Michigan, Ann Arbor, MI 48109, United States
| | - Fei Wen
- Department of Chemical Engineering, University of Michigan, Ann Arbor, MI 48109, United States; Catalysis Science and Technology Institute, University of Michigan, Ann Arbor, MI 48109, United States.
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3
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Vargas BDO, dos Santos JR, Pereira GAG, de Mello FDSB. An atlas of rational genetic engineering strategies for improved xylose metabolism in Saccharomyces cerevisiae. PeerJ 2023; 11:e16340. [PMID: 38047029 PMCID: PMC10691383 DOI: 10.7717/peerj.16340] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/18/2023] [Accepted: 10/03/2023] [Indexed: 12/05/2023] Open
Abstract
Xylose is the second most abundant carbohydrate in nature, mostly present in lignocellulosic material, and representing an appealing feedstock for molecule manufacturing through biotechnological routes. However, Saccharomyces cerevisiae-a microbial cell widely used industrially for ethanol production-is unable to assimilate this sugar. Hence, in a world with raising environmental awareness, the efficient fermentation of pentoses is a crucial bottleneck to producing biofuels from renewable biomass resources. In this context, advances in the genetic mapping of S. cerevisiae have contributed to noteworthy progress in the understanding of xylose metabolism in yeast, as well as the identification of gene targets that enable the development of tailored strains for cellulosic ethanol production. Accordingly, this review focuses on the main strategies employed to understand the network of genes that are directly or indirectly related to this phenotype, and their respective contributions to xylose consumption in S. cerevisiae, especially for ethanol production. Altogether, the information in this work summarizes the most recent and relevant results from scientific investigations that endowed S. cerevisiae with an outstanding capability for commercial ethanol production from xylose.
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Affiliation(s)
- Beatriz de Oliveira Vargas
- Department of Genetics, Evolution, Microbiology, and Immunology, Institute of Biology, Universidade Estadual de Campinas, Campinas, Brazil
| | - Jade Ribeiro dos Santos
- Department of Genetics, Evolution, Microbiology, and Immunology, Institute of Biology, Universidade Estadual de Campinas, Campinas, Brazil
| | - Gonçalo Amarante Guimarães Pereira
- Department of Genetics, Evolution, Microbiology, and Immunology, Institute of Biology, Universidade Estadual de Campinas, Campinas, Brazil
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Nijland JG, Zhang X, Driessen AJM. D-xylose accelerated death of pentose metabolizing Saccharomyces cerevisiae. BIOTECHNOLOGY FOR BIOFUELS AND BIOPRODUCTS 2023; 16:67. [PMID: 37069654 PMCID: PMC10111712 DOI: 10.1186/s13068-023-02320-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/24/2022] [Accepted: 04/10/2023] [Indexed: 04/19/2023]
Abstract
Rapid and effective consumption of D-xylose by Saccharomyces cerevisiae is essential for cost-efficient cellulosic bioethanol production. Hence, heterologous D-xylose metabolic pathways have been introduced into S. cerevisiae. An effective solution is based on a xylose isomerase in combination with the overexpression of the xylulose kinase (Xks1) and all genes of the non-oxidative branch of the pentose phosphate pathway. Although this strain is capable of consuming D-xylose, growth inhibition occurs at higher D-xylose concentrations, even abolishing growth completely at 8% D-xylose. The decreased growth rates are accompanied by significantly decreased ATP levels. A key ATP-utilizing step in D-xylose metabolism is the phosphorylation of D-xylulose by Xks1. Replacement of the constitutive promoter of XKS1 by the galactose tunable promoter Pgal10 allowed the controlled expression of this gene over a broad range. By decreasing the expression levels of XKS1, growth at high D-xylose concentrations could be restored concomitantly with increased ATP levels and high rates of xylose metabolism. These data show that in fermentations with high D-xylose concentrations, too high levels of Xks1 cause a major drain on the cellular ATP levels thereby reducing the growth rate, ultimately causing substrate accelerated death. Hence, expression levels of XKS1 in S. cerevisiae needs to be tailored for the specific growth conditions and robust D-xylose metabolism.
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Affiliation(s)
- Jeroen G Nijland
- Molecular Microbiology, Groningen Biomolecular Sciences and Biotechnology, Nijenborgh 7, 9747AG, Groningen, The Netherlands
| | - Xiaohuan Zhang
- Molecular Microbiology, Groningen Biomolecular Sciences and Biotechnology, Nijenborgh 7, 9747AG, Groningen, The Netherlands
| | - Arnold J M Driessen
- Molecular Microbiology, Groningen Biomolecular Sciences and Biotechnology, Nijenborgh 7, 9747AG, Groningen, The Netherlands.
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Identification of Mutations Responsible for Improved Xylose Utilization in an Adapted Xylose Isomerase Expressing Saccharomyces cerevisiae Strain. FERMENTATION 2022. [DOI: 10.3390/fermentation8120669] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022] Open
Abstract
Economic conversion of biomass to biofuels and chemicals requires efficient and complete utilization of xylose. Saccharomyces cerevisiae strains engineered for xylose utilization are still considerably limited in their overall ability to metabolize xylose. In this study, we identified causative mutations resulting in improved xylose fermentation of an adapted S. cerevisiae strain expressing codon-optimized xylose isomerase and xylulokinase genes from the rumen bacterium Prevotella ruminicola. Genome sequencing identified single-nucleotide polymorphisms in seven open reading frames. Tetrad analysis showed that mutations in both PBS2 and PHO13 genes were required for increased xylose utilization. Single deletion of either PBS2 or PHO13 did not improve xylose utilization in strains expressing the xylose isomerase pathway. Saccharomyces can also be engineered for xylose metabolism using the xylose reductase/xylitol dehydrogenase genes from Scheffersomyces stipitis. In strains expressing the xylose reductase pathway, single deletion of PHO13 did show a significant increase xylose utilization, and further improvement in growth and fermentation was seen when PBS2 was also deleted. These findings will extend the understanding of metabolic limitations for xylose utilization in S. cerevisiae as well as understanding of how they differ among strains engineered with two different xylose utilization pathways.
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Wang XH, Zhao C, Lu XY, Zong H, Zhuge B. Production of Caffeic Acid with Co-fermentation of Xylose and Glucose by Multi-modular Engineering in Candida glycerinogenes. ACS Synth Biol 2022; 11:900-908. [PMID: 35138824 DOI: 10.1021/acssynbio.1c00535] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Caffeic acid (CA), a natural phenolic compound, has important medicinal value and market potential. In this study, we report a metabolic engineering strategy for the biosynthesis of CA in Candida glycerinogenes using xylose and glucose. The availability of precursors was increased by optimization of the shikimate (SA) pathway and the aromatic amino acid pathway. Subsequently, the carbon flux into the SA pathway was maximized by introducing a xylose metabolic pathway and optimizing the xylose assimilation pathway. Eventually, a high yielding strain CG19 was obtained, which reached a yield of 4.61 mg/g CA from mixed sugar, which was 1.2-fold higher than that of glucose. The CA titer in the 5 L bioreactor reached 431.45 mg/L with a yield of 8.63 mg/g of mixed sugar. These promising results demonstrate the great advantages of mixed sugar over glucose for high-yield production of CA. This is the first report to produce CA in C. glycerinogenes with xylose and glucose as carbon sources, which developed a promising strategy for the efficient production of high-value aromatic compounds.
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Affiliation(s)
- Xi-Hui Wang
- The Key Laboratory of Industrial Biotechnology, Ministry of Education, School of Biotechnology, Jiangnan University, Wuxi 214122, China
- The Key Laboratory of Carbohydrate Chemistry and Biotechnology, Ministry of Education, School of Biotechnology, Jiangnan University, Wuxi 214122, China
- Research Centre of Industrial Microbiology, School of Biotechnology, Jiangnan University, Wuxi 214122, China
| | - Cui Zhao
- The Key Laboratory of Industrial Biotechnology, Ministry of Education, School of Biotechnology, Jiangnan University, Wuxi 214122, China
- The Key Laboratory of Carbohydrate Chemistry and Biotechnology, Ministry of Education, School of Biotechnology, Jiangnan University, Wuxi 214122, China
- Research Centre of Industrial Microbiology, School of Biotechnology, Jiangnan University, Wuxi 214122, China
| | - Xin-Yao Lu
- The Key Laboratory of Industrial Biotechnology, Ministry of Education, School of Biotechnology, Jiangnan University, Wuxi 214122, China
- The Key Laboratory of Carbohydrate Chemistry and Biotechnology, Ministry of Education, School of Biotechnology, Jiangnan University, Wuxi 214122, China
- Research Centre of Industrial Microbiology, School of Biotechnology, Jiangnan University, Wuxi 214122, China
| | - Hong Zong
- The Key Laboratory of Industrial Biotechnology, Ministry of Education, School of Biotechnology, Jiangnan University, Wuxi 214122, China
- The Key Laboratory of Carbohydrate Chemistry and Biotechnology, Ministry of Education, School of Biotechnology, Jiangnan University, Wuxi 214122, China
- Research Centre of Industrial Microbiology, School of Biotechnology, Jiangnan University, Wuxi 214122, China
| | - Bin Zhuge
- The Key Laboratory of Industrial Biotechnology, Ministry of Education, School of Biotechnology, Jiangnan University, Wuxi 214122, China
- The Key Laboratory of Carbohydrate Chemistry and Biotechnology, Ministry of Education, School of Biotechnology, Jiangnan University, Wuxi 214122, China
- Research Centre of Industrial Microbiology, School of Biotechnology, Jiangnan University, Wuxi 214122, China
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7
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Kuanyshev N, Deewan A, Jagtap SS, Liu J, Selvam B, Chen LQ, Shukla D, Rao CV, Jin YS. Identification and analysis of sugar transporters capable of co-transporting glucose and xylose simultaneously. Biotechnol J 2021; 16:e2100238. [PMID: 34418308 DOI: 10.1002/biot.202100238] [Citation(s) in RCA: 14] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/05/2021] [Revised: 08/04/2021] [Accepted: 08/18/2021] [Indexed: 11/09/2022]
Abstract
Simultaneous co-fermentation of glucose and xylose is a key desired trait of engineered Saccharomyces cerevisiae for efficient and rapid production of biofuels and chemicals. However, glucose strongly inhibits xylose transport by endogenous hexose transporters of S. cerevisiae. We identified structurally distant sugar transporters (Lipomyces starkeyi LST1_205437 and Arabidopsis thaliana AtSWEET7) capable of co-transporting glucose and xylose from previously unexplored oleaginous yeasts and plants. Kinetic analysis showed that LST1_205437 had lenient glucose inhibition on xylose transport and AtSWEET7 transported glucose and xylose simultaneously with no inhibition. Modelling studies of LST1_205437 revealed that Ala335 residue at sugar binding site can accommodates both glucose and xylose. Docking studies with AtSWEET7 revealed that Trp59, Trp183, Asn145, and Asn179 residues stabilized the interactions with sugars, allowing both xylose and glucose to be co-transported. In addition, we altered sugar preference of LST1_205437 by single amino acid mutation at Asn365. Our findings provide a new mechanistic insight on glucose and xylose transport mechanism of sugar transporters and the identified sugar transporters can be employed to develop engineered yeast strains for producing cellulosic biofuels and chemicals.
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Affiliation(s)
- Nurzhan Kuanyshev
- DOE Center for Advanced Bioenergy and Bioproducts Innovation University of Illinois at Urbana-Champaign, Urbana, Illinois, USA.,Carl R. Woese Institute for Genomic Biology, University of Illinois at Urbana-Champaign, Urbana, Illinois, USA
| | - Anshu Deewan
- DOE Center for Advanced Bioenergy and Bioproducts Innovation University of Illinois at Urbana-Champaign, Urbana, Illinois, USA.,Carl R. Woese Institute for Genomic Biology, University of Illinois at Urbana-Champaign, Urbana, Illinois, USA.,Department of Chemical and Biomolecular Engineering, University of Illinois at Urbana-Champaign, Urbana, Illinois, USA
| | - Sujit Sadashiv Jagtap
- DOE Center for Advanced Bioenergy and Bioproducts Innovation University of Illinois at Urbana-Champaign, Urbana, Illinois, USA.,Department of Chemical and Biomolecular Engineering, University of Illinois at Urbana-Champaign, Urbana, Illinois, USA
| | - Jingjing Liu
- DOE Center for Advanced Bioenergy and Bioproducts Innovation University of Illinois at Urbana-Champaign, Urbana, Illinois, USA.,Carl R. Woese Institute for Genomic Biology, University of Illinois at Urbana-Champaign, Urbana, Illinois, USA
| | - Balaji Selvam
- Department of Chemical and Biomolecular Engineering, University of Illinois at Urbana-Champaign, Urbana, Illinois, USA
| | - Li-Qing Chen
- DOE Center for Advanced Bioenergy and Bioproducts Innovation University of Illinois at Urbana-Champaign, Urbana, Illinois, USA.,Department of Plant Biology, University of Illinois at Urbana-Champaign, Urbana, Illinois, USA
| | - Diwakar Shukla
- Department of Chemical and Biomolecular Engineering, University of Illinois at Urbana-Champaign, Urbana, Illinois, USA.,Department of Plant Biology, University of Illinois at Urbana-Champaign, Urbana, Illinois, USA.,NIH Center for Macromolecular Modeling and Bioinformatics, University of Illinois at Urbana-Champaign, Urbana, Illinois, USA.,Beckman Institute for Advanced Science and Technology, University of Illinois at Urbana-Champaign, Urbana, Illinois, USA
| | - Christopher V Rao
- DOE Center for Advanced Bioenergy and Bioproducts Innovation University of Illinois at Urbana-Champaign, Urbana, Illinois, USA.,Carl R. Woese Institute for Genomic Biology, University of Illinois at Urbana-Champaign, Urbana, Illinois, USA.,Department of Chemical and Biomolecular Engineering, University of Illinois at Urbana-Champaign, Urbana, Illinois, USA
| | - Yong-Su Jin
- DOE Center for Advanced Bioenergy and Bioproducts Innovation University of Illinois at Urbana-Champaign, Urbana, Illinois, USA.,Carl R. Woese Institute for Genomic Biology, University of Illinois at Urbana-Champaign, Urbana, Illinois, USA.,Department of Food Science and Human Nutrition, University of Illinois at Urbana-Champaign, Urbana, Illinois, USA
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8
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Zan X, Sun J, Chu L, Cui F, Huo S, Song Y, Koffas MAG. Improved glucose and xylose co-utilization by overexpression of xylose isomerase and/or xylulokinase genes in oleaginous fungus Mucor circinelloides. Appl Microbiol Biotechnol 2021; 105:5565-5575. [PMID: 34215904 DOI: 10.1007/s00253-021-11392-x] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/05/2021] [Revised: 04/28/2021] [Accepted: 06/07/2021] [Indexed: 12/17/2022]
Abstract
Most of the oleaginous microorganisms cannot assimilate xylose in the presence of glucose, which is the major bottleneck in the bioconversion of lignocellulose to biodiesel. Our present study revealed that overexpression of xylose isomerase (XI) gene xylA or xylulokinase (XK) gene xks1 increased the xylose consumption by 25 to 37% and enhanced the lipid content by 8 to 28% during co-fermentation of glucose and xylose. In xylA overexpressing strain Mc-XI, the activity of XI was 1.8-fold higher and the mRNA level of xylA at 24 h and 48 h was 11- and 13-fold higher than that of the control, respectively. In xks1 overexpressing strain Mc-XK, the mRNA level of xks1 was 4- to 11-fold of that of the control strain and the highest XK activity of 950 nmol min-1 mg-1 at 72 h which was 2-fold higher than that of the control. Additionally, expression of a translational fusion of xylA and xks1 further enhanced the xylose utilization rate by 45%. Our results indicated that overexpression of xylA and/or xks1 is a promising strategy to improve the xylose and glucose co-utilization, alleviate the glucose repression, and produce lipid from lignocellulosic biomass in the oleaginous fungus M. circinelloides. KEY POINTS: • Overexpressing xylA or xks1 increased the xylose consumption and the lipid content. • The xylose isomerase activity and the xylA mRNA level were enhanced in strain Mc-XI. • Co-expression of xylA and xks1 further enhanced the xylose utilization rate by 45%.
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Affiliation(s)
- Xinyi Zan
- School of Food and Biological Engineering, Jiangsu University, Zhenjiang, 212013, People's Republic of China
| | - Jianing Sun
- School of Food and Biological Engineering, Jiangsu University, Zhenjiang, 212013, People's Republic of China
| | - Linfang Chu
- School of Food Science and Technology, Jiang University, Wuxi, 214000, People's Republic of China
| | - Fengjie Cui
- School of Food and Biological Engineering, Jiangsu University, Zhenjiang, 212013, People's Republic of China
| | - Shuhao Huo
- School of Food and Biological Engineering, Jiangsu University, Zhenjiang, 212013, People's Republic of China
| | - Yuanda Song
- Colin Ratledge Center for Microbial Lipids, School of Agriculture Engineering and Food Science, Shandong University of Technology, Zibo, 255049, People's Republic of China.
| | - Mattheos A G Koffas
- Center for Biotechnology and Interdisciplinary Studies, Rensselaer Polytechnic Institute, Troy, NY, 12180, USA
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9
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Shi XC, Zhang Y, Wang T, Wang XC, Lv HB, Laborda P, Duan TT. Metabolic and transcriptional analysis of recombinant Saccharomyces?cerevisiae for xylose fermentation: a feasible and efficient approach. IEEE J Biomed Health Inform 2021; 26:2425-2434. [PMID: 34077376 DOI: 10.1109/jbhi.2021.3085313] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Lignocellulose is an abundant xylose-containing biomass found in agricultural wastes, and has arisen as a suitable alternative to fossil fuels for the production of bioethanol. Although Saccharomyces cerevisiae has been thoroughly used for the production of bioethanol, its potential to utilize lignocellulose remains poorly understood. In this work, xylose-metabolic genes of Pichia stipitis and Candida tropicalis, under the control of different promoters, were introduced into S. cerevisiae. RNA-seq analysis was use to examine the response of S. cerevisiae metabolism to the introduction of xylose-metabolic genes. The use of the PGK1 promoter to drive xylitol dehydrogenase (XDH) expression, instead of the TEF1 promoter, improved xylose utilization in ?XR-pXDH? strain by overexpressing xylose reductase (XR) and XDH from C. tropicalis, enhancing the production of xylitol (13.66 ? 0.54 g/L after 6 days fermentation). Overexpression of xylulokinase and XR/XDH from P. stipitis remarkably decreased xylitol accumulation (1.13 ? 0.06 g/L and 0.89 ? 0.04 g/L xylitol, respectively) and increased ethanol production (196.14% and 148.50% increases during the xylose utilization stage, respectively), in comparison with the results of XR-pXDH. This result may be produced due to the enhanced xylose transport, Embden?Meyerhof and pentose phosphate pathways, as well as alleviated oxidative stress. The low xylose consumption rate in these recombinant strains comparing with P. stipitis and C. tropicalis may be explained by the insufficient supplementation of NADPH and NAD+. The results obtained in this work provide new insights on the potential utilization of xylose using bioengineered S. cerevisiae strains.
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10
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Shin M, Park H, Kim S, Oh EJ, Jeong D, Florencia C, Kim KH, Jin YS, Kim SR. Transcriptomic Changes Induced by Deletion of Transcriptional Regulator GCR2 on Pentose Sugar Metabolism in Saccharomyces cerevisiae. Front Bioeng Biotechnol 2021; 9:654177. [PMID: 33842449 PMCID: PMC8027353 DOI: 10.3389/fbioe.2021.654177] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/15/2021] [Accepted: 03/08/2021] [Indexed: 11/13/2022] Open
Abstract
Being a microbial host for lignocellulosic biofuel production, Saccharomyces cerevisiae needs to be engineered to express a heterologous xylose pathway; however, it has been challenging to optimize the engineered strain for efficient and rapid fermentation of xylose. Deletion of PHO13 (Δpho13) has been reported to be a crucial genetic perturbation in improving xylose fermentation. A confirmed mechanism of the Δpho13 effect on xylose fermentation is that the Δpho13 transcriptionally activates the genes in the non-oxidative pentose phosphate pathway (PPP). In the current study, we found a couple of engineered strains, of which phenotypes were not affected by Δpho13 (Δpho13-negative), among many others we examined. Genome resequencing of the Δpho13-negative strains revealed that a loss-of-function mutation in GCR2 was responsible for the phenotype. Gcr2 is a global transcriptional factor involved in glucose metabolism. The results of RNA-seq confirmed that the deletion of GCR2 (Δgcr2) led to the upregulation of PPP genes as well as downregulation of glycolytic genes, and changes were more significant under xylose conditions than those under glucose conditions. Although there was no synergistic effect between Δpho13 and Δgcr2 in improving xylose fermentation, these results suggested that GCR2 is a novel knockout target in improving lignocellulosic ethanol production.
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Affiliation(s)
- Minhye Shin
- Department of Agricultural Biotechnology, Research Institute of Agriculture and Life Science, Seoul National University, Seoul, South Korea
| | - Heeyoung Park
- School of Food Science and Biotechnology, Kyungpook National University, Daegu, South Korea
| | - Sooah Kim
- Department of Environment Science and Biotechnology, Jeonju University, Jeonju, South Korea
| | - Eun Joong Oh
- Department of Food Science, Purdue University, West Lafayette, IN, United States
| | - Deokyeol Jeong
- School of Food Science and Biotechnology, Kyungpook National University, Daegu, South Korea
| | - Clarissa Florencia
- Department of Food Science and Human Nutrition, University of Illinois at Urbana-Champaign, Urbana, IL, United States
| | - Kyoung Heon Kim
- Department of Biotechnology, Graduate School, Korea University, Seoul, South Korea
| | - Yong-Su Jin
- Department of Food Science and Human Nutrition, University of Illinois at Urbana-Champaign, Urbana, IL, United States
| | - Soo Rin Kim
- School of Food Science and Biotechnology, Kyungpook National University, Daegu, South Korea
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11
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Characterisation of novel regulatory sequences compatible with modular assembly in the diatom Phaeodactylum tricornutum. ALGAL RES 2021. [DOI: 10.1016/j.algal.2020.102159] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
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12
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Ruchala J, Sibirny AA. Pentose metabolism and conversion to biofuels and high-value chemicals in yeasts. FEMS Microbiol Rev 2020; 45:6034013. [PMID: 33316044 DOI: 10.1093/femsre/fuaa069] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/20/2020] [Accepted: 12/09/2020] [Indexed: 12/15/2022] Open
Abstract
Pentose sugars are widespread in nature and two of them, D-xylose and L-arabinose belong to the most abundant sugars being the second and third by abundance sugars in dry plant biomass (lignocellulose) and in general on planet. Therefore, it is not surprising that metabolism and bioconversion of these pentoses attract much attention. Several different pathways of D-xylose and L-arabinose catabolism in bacteria and yeasts are known. There are even more common and really ubiquitous though not so abundant pentoses, D-ribose and 2-deoxy-D-ribose, the constituents of all living cells. Thus, ribose metabolism is example of endogenous metabolism whereas metabolism of other pentoses, including xylose and L-arabinose, represents examples of the metabolism of foreign exogenous compounds which normally are not constituents of yeast cells. As a rule, pentose degradation by the wild-type strains of microorganisms does not lead to accumulation of high amounts of valuable substances; however, productive strains have been obtained by random selection and metabolic engineering. There are numerous reviews on xylose and (less) L-arabinose metabolism and conversion to high value substances; however, they mostly are devoted to bacteria or the yeast Saccharomyces cerevisiae. This review is devoted to reviewing pentose metabolism and bioconversion mostly in non-conventional yeasts, which naturally metabolize xylose. Pentose metabolism in the recombinant strains of S. cerevisiae is also considered for comparison. The available data on ribose, xylose, L-arabinose transport, metabolism, regulation of these processes, interaction with glucose catabolism and construction of the productive strains of high-value chemicals or pentose (ribose) itself are described. In addition, genome studies of the natural xylose metabolizing yeasts and available tools for their molecular research are reviewed. Metabolism of other pentoses (2-deoxyribose, D-arabinose, lyxose) is briefly reviewed.
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Affiliation(s)
- Justyna Ruchala
- Department of Microbiology and Molecular Genetics, University of Rzeszow, Zelwerowicza 4, Rzeszow 35-601, Poland.,Department of Molecular Genetics and Biotechnology, Institute of Cell Biology NAS of Ukraine, Drahomanov Street, 14/16, Lviv 79005, Ukraine
| | - Andriy A Sibirny
- Department of Microbiology and Molecular Genetics, University of Rzeszow, Zelwerowicza 4, Rzeszow 35-601, Poland.,Department of Molecular Genetics and Biotechnology, Institute of Cell Biology NAS of Ukraine, Drahomanov Street, 14/16, Lviv 79005, Ukraine
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13
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Compartmentalized microbes and co-cultures in hydrogels for on-demand bioproduction and preservation. Nat Commun 2020; 11:563. [PMID: 32019917 PMCID: PMC7000784 DOI: 10.1038/s41467-020-14371-4] [Citation(s) in RCA: 108] [Impact Index Per Article: 27.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/18/2019] [Accepted: 01/03/2020] [Indexed: 01/13/2023] Open
Abstract
Most mono- and co-culture bioprocess applications rely on large-scale suspension fermentation technologies that are not easily portable, reusable, or suitable for on-demand production. Here, we describe a hydrogel system for harnessing the bioactivity of embedded microbes for on-demand small molecule and peptide production in microbial mono-culture and consortia. This platform bypasses the challenges of engineering a multi-organism consortia by utilizing a temperature-responsive, shear-thinning hydrogel to compartmentalize organisms into polymeric hydrogels that control the final consortium composition and dynamics without the need for synthetic control of mutualism. We demonstrate that these hydrogels provide protection from preservation techniques (including lyophilization) and can sustain metabolic function for over 1 year of repeated use. This approach was utilized for the production of four chemical compounds, a peptide antibiotic, and carbohydrate catabolism by using either mono-cultures or co-cultures. The printed microbe-laden hydrogel constructs’ efficiency in repeated production phases, both pre- and post-preservation, outperforms liquid culture. Large scale suspension fermentation technology is not easily portable or reusable. Here the authors describe a hydrogel system suitable for long-term and reusable production with both single and multi-organism consortia.
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14
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Ruchala J, Kurylenko OO, Dmytruk KV, Sibirny AA. Construction of advanced producers of first- and second-generation ethanol in Saccharomyces cerevisiae and selected species of non-conventional yeasts (Scheffersomyces stipitis, Ogataea polymorpha). J Ind Microbiol Biotechnol 2019; 47:109-132. [PMID: 31637550 PMCID: PMC6970964 DOI: 10.1007/s10295-019-02242-x] [Citation(s) in RCA: 32] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/29/2019] [Accepted: 10/01/2019] [Indexed: 12/20/2022]
Abstract
This review summarizes progress in the construction of efficient yeast ethanol producers from glucose/sucrose and lignocellulose. Saccharomyces cerevisiae is the major industrial producer of first-generation ethanol. The different approaches to increase ethanol yield and productivity from glucose in S. cerevisiae are described. Construction of the producers of second-generation ethanol is described for S. cerevisiae, one of the best natural xylose fermenters, Scheffersomyces stipitis and the most thermotolerant yeast known Ogataea polymorpha. Each of these organisms has some advantages and drawbacks. S. cerevisiae is the primary industrial ethanol producer and is the most ethanol tolerant natural yeast known and, however, cannot metabolize xylose. S. stipitis can effectively ferment both glucose and xylose and, however, has low ethanol tolerance and requires oxygen for growth. O. polymorpha grows and ferments at high temperatures and, however, produces very low amounts of ethanol from xylose. Review describes how the mentioned drawbacks could be overcome.
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Affiliation(s)
- Justyna Ruchala
- Department of Microbiology and Biotechnology, University of Rzeszow, Zelwerowicza 4, 35-601, Rzeszow, Poland
| | - Olena O Kurylenko
- Department of Molecular Genetics and Biotechnology, Institute of Cell Biology, NAS of Ukraine, Drahomanov Street, 14/16, Lviv, 79005, Ukraine
| | - Kostyantyn V Dmytruk
- Department of Molecular Genetics and Biotechnology, Institute of Cell Biology, NAS of Ukraine, Drahomanov Street, 14/16, Lviv, 79005, Ukraine
| | - Andriy A Sibirny
- Department of Microbiology and Biotechnology, University of Rzeszow, Zelwerowicza 4, 35-601, Rzeszow, Poland.
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15
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Osiro KO, Borgström C, Brink DP, Fjölnisdóttir BL, Gorwa-Grauslund MF. Exploring the xylose paradox in Saccharomyces cerevisiae through in vivo sugar signalomics of targeted deletants. Microb Cell Fact 2019; 18:88. [PMID: 31122246 PMCID: PMC6532234 DOI: 10.1186/s12934-019-1141-x] [Citation(s) in RCA: 27] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/23/2019] [Accepted: 05/17/2019] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND There have been many successful strategies to implement xylose metabolism in Saccharomyces cerevisiae, but no effort has so far enabled xylose utilization at rates comparable to that of glucose (the preferred sugar of this yeast). Many studies have pointed towards the engineered yeast not sensing that xylose is a fermentable carbon source despite growing and fermenting on it, which is paradoxical. We have previously used fluorescent biosensor strains to in vivo monitor the sugar signalome in yeast engineered with xylose reductase and xylitol dehydrogenase (XR/XDH) and have established that S. cerevisiae senses high concentrations of xylose with the same signal as low concentration of glucose, which may explain the poor utilization. RESULTS In the present study, we evaluated the effects of three deletions (ira2∆, isu1∆ and hog1∆) that have recently been shown to display epistatic effects on a xylose isomerase (XI) strain. Through aerobic and anaerobic characterization, we showed that the proposed effects in XI strains were for the most part also applicable in the XR/XDH background. The ira2∆isu1∆ double deletion led to strains with the highest specific xylose consumption- and ethanol production rates but also the lowest biomass titre. The signalling response revealed that ira2∆isu1∆ changed the low glucose-signal in the background strain to a simultaneous signalling of high and low glucose, suggesting that engineering of the signalome can improve xylose utilization. CONCLUSIONS The study was able to correlate the previously proposed beneficial effects of ira2∆, isu1∆ and hog1∆ on S. cerevisiae xylose uptake, with a change in the sugar signalome. This is in line with our previous hypothesis that the key to resolve the xylose paradox lies in the sugar sensing and signalling networks. These results indicate that the future engineering targets for improved xylose utilization should probably be sought not in the metabolic networks, but in the signalling ones.
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Affiliation(s)
- Karen O Osiro
- Applied Microbiology, Department of Chemistry, Lund University, Lund, Sweden
| | - Celina Borgström
- Applied Microbiology, Department of Chemistry, Lund University, Lund, Sweden
| | - Daniel P Brink
- Applied Microbiology, Department of Chemistry, Lund University, Lund, Sweden
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16
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Wagner ER, Myers KS, Riley NM, Coon JJ, Gasch AP. PKA and HOG signaling contribute separable roles to anaerobic xylose fermentation in yeast engineered for biofuel production. PLoS One 2019; 14:e0212389. [PMID: 31112537 PMCID: PMC6528989 DOI: 10.1371/journal.pone.0212389] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2019] [Accepted: 04/29/2019] [Indexed: 12/25/2022] Open
Abstract
Lignocellulosic biomass offers a sustainable source for biofuel production that does not compete with food-based cropping systems. Importantly, two critical bottlenecks prevent economic adoption: many industrially relevant microorganisms cannot ferment pentose sugars prevalent in lignocellulosic medium, leaving a significant amount of carbon unutilized. Furthermore, chemical biomass pretreatment required to release fermentable sugars generates a variety of toxins, which inhibit microbial growth and metabolism, specifically limiting pentose utilization in engineered strains. Here we dissected genetic determinants of anaerobic xylose fermentation and stress tolerance in chemically pretreated corn stover biomass, called hydrolysate. We previously revealed that loss-of-function mutations in the stress-responsive MAP kinase HOG1 and negative regulator of the RAS/Protein Kinase A (PKA) pathway, IRA2, enhances anaerobic xylose fermentation. However, these mutations likely reduce cells' ability to tolerate the toxins present in lignocellulosic hydrolysate, making the strain especially vulnerable to it. We tested the contributions of Hog1 and PKA signaling via IRA2 or PKA negative regulatory subunit BCY1 to metabolism, growth, and stress tolerance in corn stover hydrolysate and laboratory medium with mixed sugars. We found mutations causing upregulated PKA activity increase growth rate and glucose consumption in various media but do not have a specific impact on xylose fermentation. In contrast, mutation of HOG1 specifically increased xylose usage. We hypothesized improving stress tolerance would enhance the rate of xylose consumption in hydrolysate. Surprisingly, increasing stress tolerance did not augment xylose fermentation in lignocellulosic medium in this strain background, suggesting other mechanisms besides cellular stress limit this strain's ability for anaerobic xylose fermentation in hydrolysate.
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Affiliation(s)
- Ellen R. Wagner
- Great Lakes Bioenergy Research Center, University of Wisconsin–Madison, Madison, WI United States of America
| | - 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
| | - 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
- Genome Center of Wisconsin, University of Wisconsin–Madison, Madison, WI United States of America
- Laboratory of Genetics, University of Wisconsin–Madison, Madison, WI United States of America
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17
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Wierzbicki MP, Maloney V, Mizrachi E, Myburg AA. Xylan in the Middle: Understanding Xylan Biosynthesis and Its Metabolic Dependencies Toward Improving Wood Fiber for Industrial Processing. FRONTIERS IN PLANT SCIENCE 2019; 10:176. [PMID: 30858858 PMCID: PMC6397879 DOI: 10.3389/fpls.2019.00176] [Citation(s) in RCA: 30] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/09/2018] [Accepted: 02/04/2019] [Indexed: 05/14/2023]
Abstract
Lignocellulosic biomass, encompassing cellulose, lignin and hemicellulose in plant secondary cell walls (SCWs), is the most abundant source of renewable materials on earth. Currently, fast-growing woody dicots such as Eucalyptus and Populus trees are major lignocellulosic (wood fiber) feedstocks for bioproducts such as pulp, paper, cellulose, textiles, bioplastics and other biomaterials. Processing wood for these products entails separating the biomass into its three main components as efficiently as possible without compromising yield. Glucuronoxylan (xylan), the main hemicellulose present in the SCWs of hardwood trees carries chemical modifications that are associated with SCW composition and ultrastructure, and affect the recalcitrance of woody biomass to industrial processing. In this review we highlight the importance of xylan properties for industrial wood fiber processing and how gaining a greater understanding of xylan biosynthesis, specifically xylan modification, could yield novel biotechnology approaches to reduce recalcitrance or introduce novel processing traits. Altering xylan modification patterns has recently become a focus of plant SCW studies due to early findings that altered modification patterns can yield beneficial biomass processing traits. Additionally, it has been noted that plants with altered xylan composition display metabolic differences linked to changes in precursor usage. We explore the possibility of using systems biology and systems genetics approaches to gain insight into the coordination of SCW formation with other interdependent biological processes. Acetyl-CoA, s-adenosylmethionine and nucleotide sugars are precursors needed for xylan modification, however, the pathways which produce metabolic pools during different stages of fiber cell wall formation still have to be identified and their co-regulation during SCW formation elucidated. The crucial dependence on precursor metabolism provides an opportunity to alter xylan modification patterns through metabolic engineering of one or more of these interdependent pathways. The complexity of xylan biosynthesis and modification is currently a stumbling point, but it may provide new avenues for woody biomass engineering that are not possible for other biopolymers.
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Affiliation(s)
| | | | | | - Alexander A. Myburg
- Department of Biochemistry, Genetics and Microbiology, Forestry and Agricultural Biotechnology Institute (FABI), University of Pretoria, Pretoria, South Africa
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18
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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: 32] [Impact Index Per Article: 6.4] [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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19
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Gao X, Caiyin Q, Zhao F, Wu Y, Lu W. Engineering Saccharomyces cerevisiae for Enhanced Production of Protopanaxadiol with Cofermentation of Glucose and Xylose. JOURNAL OF AGRICULTURAL AND FOOD CHEMISTRY 2018; 66:12009-12016. [PMID: 30350965 DOI: 10.1021/acs.jafc.8b04916] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/06/2023]
Abstract
Protopanaxadiol (PPD), an active triterpene compound, is the precursor of high-value ginsenosides. In this study, we report a strategy for the enhancement of PPD production in Saccharomyces cerevisiae by cofermentation of glucose and xylose. In mixed sugar fermentation, strain GW6 showed higher PPD titer and yield than that obtained from glucose cultivation. Then, engineering strategies were implemented on GW6 to enhance the PPD yields, such as adjustment of the central carbon metabolism, optimization of the mevalonate pathway, reinforcement of the xylose assimilation pathway, and regulation of cofactor balance, namely, overexpression of xPK/PTA, ERG10/ERG12/ERG13, XYL1/XYL2/TAL1, and POS5, respectively. In particular, the final obtained strain GW10, harboring overexpressed POS5, exhibited the highest PPD yield, which was 2.06 mg of PPD/g of mixed sugar. In a 5-L fermenter, PPD titer reached 152.37 mg/L. These promising results demonstrate the great advantages of mixed sugar over glucose for high-yield production of PPD.
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Affiliation(s)
- Xiao Gao
- School of Chemical Engineering and Technology , Tianjin University , Tianjin 300072 , People's Republic of China
| | - Qinggele Caiyin
- School of Chemical Engineering and Technology , Tianjin University , Tianjin 300072 , People's Republic of China
| | - Fanglong Zhao
- School of Chemical Engineering and Technology , Tianjin University , Tianjin 300072 , People's Republic of China
| | - Yufen Wu
- School of Chemical Engineering and Technology , Tianjin University , Tianjin 300072 , People's Republic of China
| | - Wenyu Lu
- School of Chemical Engineering and Technology , Tianjin University , Tianjin 300072 , People's Republic of China
- Key Laboratory of System Bioengineering (Tianjin University) , Ministry of Education , Tianjin 300072 , People's Republic of China
- SynBio Research Platform , Collaborative Innovation Center of Chemical Science and Engineering (Tianjin) , Tianjin 300072 , People's Republic of China
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20
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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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21
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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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22
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Gibney PA, Schieler A, Chen JC, Bacha-Hummel JM, Botstein M, Volpe M, Silverman SJ, Xu Y, Bennett BD, Rabinowitz JD, Botstein D. Common and divergent features of galactose-1-phosphate and fructose-1-phosphate toxicity in yeast. Mol Biol Cell 2018; 29:897-910. [PMID: 29444955 PMCID: PMC5896929 DOI: 10.1091/mbc.e17-11-0666] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/22/2023] Open
Abstract
Metabolic dysregulation leading to sugar-phosphate accumulation is toxic in organisms ranging from bacteria to humans. By comparing two models of sugar-phosphate toxicity in Saccharomyces cerevisiae, we demonstrate that toxicity occurs, at least in part, through multiple, isomer-specific mechanisms, rather than a single general mechanism.
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Affiliation(s)
- Patrick A Gibney
- Lewis-Sigler Institute for Integrative Genomics, Princeton University, Princeton, NJ 08544.,Calico Life Sciences LLC, South San Francisco, CA 94080.,Department of Food Science, Cornell University, Ithaca, NY 14853
| | - Ariel Schieler
- Lewis-Sigler Institute for Integrative Genomics, Princeton University, Princeton, NJ 08544
| | - Jonathan C Chen
- Lewis-Sigler Institute for Integrative Genomics, Princeton University, Princeton, NJ 08544.,Department of Chemistry, Princeton University, Princeton, NJ 08544
| | | | - Maxim Botstein
- Lewis-Sigler Institute for Integrative Genomics, Princeton University, Princeton, NJ 08544
| | - Matthew Volpe
- Lewis-Sigler Institute for Integrative Genomics, Princeton University, Princeton, NJ 08544
| | - Sanford J Silverman
- Lewis-Sigler Institute for Integrative Genomics, Princeton University, Princeton, NJ 08544
| | - Yifan Xu
- Lewis-Sigler Institute for Integrative Genomics, Princeton University, Princeton, NJ 08544.,Department of Chemistry, Princeton University, Princeton, NJ 08544
| | | | - Joshua D Rabinowitz
- Lewis-Sigler Institute for Integrative Genomics, Princeton University, Princeton, NJ 08544.,Department of Chemistry, Princeton University, Princeton, NJ 08544
| | - David Botstein
- Lewis-Sigler Institute for Integrative Genomics, Princeton University, Princeton, NJ 08544.,Calico Life Sciences LLC, South San Francisco, CA 94080.,Department of Food Science, Cornell University, Ithaca, NY 14853
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23
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Eriksen DT, Chao R, Zhao H. Applying Advanced DNA Assembly Methods to Generate Pathway Libraries. Synth Biol (Oxf) 2018. [DOI: 10.1002/9783527688104.ch16] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022] Open
Affiliation(s)
- Dawn T. Eriksen
- University of Illinois at Urbana-Champaign; Department of Chemical and Biomolecular Engineering; 600 South Mathews Avenue, Urbana IL 61801 USA
| | - Ran Chao
- University of Illinois at Urbana-Champaign; Department of Chemical and Biomolecular Engineering; 600 South Mathews Avenue, Urbana IL 61801 USA
| | - Huimin Zhao
- University of Illinois at Urbana-Champaign; Department of Chemical and Biomolecular Engineering; 600 South Mathews Avenue, Urbana IL 61801 USA
- University of Illinois at Urbana-Champaign; Departments of Chemistry, Biochemistry, and Bioengineering, 600 South Mathews Avenue; Urbana IL 61801 USA
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24
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Bioethanol a Microbial Biofuel Metabolite; New Insights of Yeasts Metabolic Engineering. FERMENTATION-BASEL 2018. [DOI: 10.3390/fermentation4010016] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
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25
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Karabín M, Jelínek L, Kotrba P, Cejnar R, Dostálek P. Enhancing the performance of brewing yeasts. Biotechnol Adv 2017; 36:691-706. [PMID: 29277309 DOI: 10.1016/j.biotechadv.2017.12.014] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2017] [Revised: 11/23/2017] [Accepted: 12/20/2017] [Indexed: 12/26/2022]
Abstract
Beer production is one of the oldest known traditional biotechnological processes, but is nowadays facing increasing demands not only for enhanced product quality, but also for improved production economics. Targeted genetic modification of a yeast strain is one way to increase beer quality and to improve the economics of beer production. In this review we will present current knowledge on traditional approaches for improving brewing strains and for rational metabolic engineering. These research efforts will, in the near future, lead to the development of a wider range of industrial strains that should increase the diversity of commercial beers.
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Affiliation(s)
- Marcel Karabín
- Department of Biotechnology, University of Chemistry and Technology, Prague, Technická 5, 16628 Prague 6, Czech Republic
| | - Lukáš Jelínek
- Department of Biotechnology, University of Chemistry and Technology, Prague, Technická 5, 16628 Prague 6, Czech Republic
| | - Pavel Kotrba
- Department of Biochemistry and Microbiology, University of Chemistry and Technology, Prague, Technická 5, 16628 Prague 6, Czech Republic
| | - Rudolf Cejnar
- Department of Biotechnology, University of Chemistry and Technology, Prague, Technická 5, 16628 Prague 6, Czech Republic
| | - Pavel Dostálek
- Department of Biotechnology, University of Chemistry and Technology, Prague, Technická 5, 16628 Prague 6, Czech Republic.
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26
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Jo JH, Park YC, Jin YS, Seo JH. Construction of efficient xylose-fermenting Saccharomyces cerevisiae through a synthetic isozyme system of xylose reductase from Scheffersomyces stipitis. BIORESOURCE TECHNOLOGY 2017; 241:88-94. [PMID: 28550778 DOI: 10.1016/j.biortech.2017.05.091] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/03/2017] [Revised: 05/13/2017] [Accepted: 05/15/2017] [Indexed: 05/12/2023]
Abstract
Engineered Saccharomyces cerevisiae has been used for ethanol production from xylose, the abundant sugar in lignocellulosic hydrolyzates. Development of engineered S. cerevisiae able to utilize xylose effectively is crucial for economical and sustainable production of fuels. To this end, the xylose-metabolic genes (XYL1, XYL2 and XYL3) from Scheffersomyces stipitis have been introduced into S. cerevisiae. The resulting engineered S. cerevisiae strains, however, often exhibit undesirable phenotypes such as slow xylose assimilation and xylitol accumulation. This work was undertaken to construct an improved xylose-fermenting strain by developing a synthetic isozyme system of xylose reductase (XR). The DXS strain having both wild XR and mutant XR showed low xylitol accumulation and fast xylose consumption compared to the engineered strains expressing only one type of XRs, resulting in improved ethanol yield and productivity. These results suggest that the introduction of the XR-based synthetic isozyme system is a promising strategy to develop efficient xylose-fermenting strains.
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Affiliation(s)
- Jung-Hyun Jo
- Department of Agricultural Biotechnology, Center for Food and Bioconvergence, Seoul National University, Seoul 08826, Republic of Korea
| | - Yong-Cheol Park
- Department of Bio and Fermentation Convergence Technology and BK21 Plus Program, Kookmin University, Seoul 03084, Republic of Korea
| | - Yong-Su Jin
- Department of Food Science and Human Nutrition, University of Illinois at Urbana-Champaign, Urbana, IL 61801, USA
| | - Jin-Ho Seo
- Department of Agricultural Biotechnology, Center for Food and Bioconvergence, Seoul National University, Seoul 08826, Republic of Korea.
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27
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Nambu-Nishida Y, Sakihama Y, Ishii J, Hasunuma T, Kondo A. Selection of yeast Saccharomyces cerevisiae promoters available for xylose cultivation and fermentation. J Biosci Bioeng 2017; 125:76-86. [PMID: 28869192 DOI: 10.1016/j.jbiosc.2017.08.001] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/11/2017] [Revised: 06/21/2017] [Accepted: 08/02/2017] [Indexed: 11/26/2022]
Abstract
To efficiently utilize xylose, a major sugar component of hemicelluloses, in Saccharomyces cerevisiae requires the proper expression of varied exogenous and endogenous genes. To expand the repertoire of promoters in engineered xylose-utilizing yeast strains, we selected promoters in S. cerevisiae during cultivation and fermentation using xylose as a carbon source. To select candidate promoters that function in the presence of xylose, we performed comprehensive gene expression analyses using xylose-utilizing yeast strains both during xylose and glucose fermentation. Based on microarray data, we chose 29 genes that showed strong, moderate, and weak expression in xylose rather than glucose fermentation. The activities of these promoters in a xylose-utilizing yeast strain were measured by lacZ reporter gene assays over time during aerobic cultivation and microaerobic fermentation, both in xylose and glucose media. In xylose media, PTDH3, PFBA1, and PTDH1 were favorable for high expression, and PSED1, PHXT7, PPDC1, PTEF1, PTPI1, and PPGK1 were acceptable for medium-high expression in aerobic cultivation, and moderate expression in microaerobic fermentation. PTEF2 allowed moderate expression in aerobic culture and weak expression in microaerobic fermentation, although it showed medium-high expression in glucose media. PZWF1 and PSOL4 allowed moderate expression in aerobic cultivation, while showing weak but clear expression in microaerobic fermentation. PALD3 and PTKL2 showed moderate promoter activity in aerobic cultivation, but showed almost no activity in microaerobic fermentation. The knowledge of promoter activities in xylose cultivation obtained in this study will permit the control of gene expression in engineered xylose-utilizing yeast strains that are used for hemicellulose fermentation.
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Affiliation(s)
- Yumiko Nambu-Nishida
- Technology Research Association of Highly Efficient Gene Design (TRAHED), 7-1-49 Minatojimaminamimachi, Chuo-ku, Kobe 650-0047, Japan; Department of Chemical Science and Engineering, Graduate School of Engineering, Kobe University, 1-1 Rokkodai-cho, Nada-ku, Kobe 657-8501, Japan
| | - Yuri Sakihama
- Graduate School of Science, Technology and Innovation, Kobe University, 1-1 Rokkodai-cho, Nada-ku, Kobe 657-8501, Japan
| | - Jun Ishii
- Graduate School of Science, Technology and Innovation, Kobe University, 1-1 Rokkodai-cho, Nada-ku, Kobe 657-8501, Japan
| | - Tomohisa Hasunuma
- Graduate School of Science, Technology and Innovation, Kobe University, 1-1 Rokkodai-cho, Nada-ku, Kobe 657-8501, Japan
| | - Akihiko Kondo
- Department of Chemical Science and Engineering, Graduate School of Engineering, Kobe University, 1-1 Rokkodai-cho, Nada-ku, Kobe 657-8501, Japan; Graduate School of Science, Technology and Innovation, Kobe University, 1-1 Rokkodai-cho, Nada-ku, Kobe 657-8501, Japan; Biomass Engineering Program, RIKEN, 1-7-22 Suehiro-cho, Tsurumi-ku, Yokohama 230-0045, Japan.
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Ali SS, Wu J, Xie R, Zhou F, Sun J, Huang M. Screening and characterizing of xylanolytic and xylose-fermenting yeasts isolated from the wood-feeding termite, Reticulitermes chinensis. PLoS One 2017; 12:e0181141. [PMID: 28704553 PMCID: PMC5509302 DOI: 10.1371/journal.pone.0181141] [Citation(s) in RCA: 40] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/29/2017] [Accepted: 06/21/2017] [Indexed: 11/20/2022] Open
Abstract
The effective fermentation of xylose remains an intractable challenge in bioethanol industry. The relevant xylanase enzyme is also in a high demand from industry for several biotechnological applications that inevitably in recent times led to many efforts for screening some novel microorganisms for better xylanase production and fermentation performance. Recently, it seems that wood-feeding termites can truly be considered as highly efficient natural bioreactors. The highly specialized gut systems of such insects are not yet fully realized, particularly, in xylose fermentation and xylanase production to advance industrial bioethanol technology as well as industrial applications of xylanases. A total of 92 strains from 18 yeast species were successfully isolated and identified from the gut of wood-feeding termite, Reticulitermes chinensis. Of these yeasts and strains, seven were identified for new species: Candida gotoi, Candida pseudorhagii, Hamamotoa lignophila, Meyerozyma guilliermondii, Sugiyamaella sp.1, Sugiyamaella sp. 2, and Sugiyamaella sp.3. Based on the phylogenetic and phenotypic characterization, the type strain of C. pseudorhagii sp. nov., which was originally designated strain SSA-1542T, was the most frequently occurred yeast from termite gut samples, showed the highly xylanolytic activity as well as D-xylose fermentation. The highest xylanase activity was recorded as 1.73 and 0.98 U/mL with xylan or D-xylose substrate, respectively, from SSA-1542T. Among xylanase-producing yeasts, four novel species were identified as D-xylose-fermenting yeasts, where the yeast, C. pseudorhagii SSA-1542T, showed the highest ethanol yield (0.31 g/g), ethanol productivity (0.31 g/L·h), and its fermentation efficiency (60.7%) in 48 h. Clearly, the symbiotic yeasts isolated from termite guts have demonstrated a competitive capability to produce xylanase and ferment xylose, suggesting that the wood-feeding termite gut is a promising reservoir for novel xylanases-producing and xylose-fermenting yeasts that are potentially valued for biorefinery industry.
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Affiliation(s)
- Sameh Samir Ali
- Biofuels Institute, School of the Environment and Safety Engineering, Jiangsu University, Zhenjiang, China
- Botany Department, Faculty of Science, Tanta University, Tanta, Egypt
| | - Jian Wu
- Biofuels Institute, School of the Environment and Safety Engineering, Jiangsu University, Zhenjiang, China
| | - Rongrong Xie
- Biofuels Institute, School of the Environment and Safety Engineering, Jiangsu University, Zhenjiang, China
| | - Feng Zhou
- Biofuels Institute, School of the Environment and Safety Engineering, Jiangsu University, Zhenjiang, China
| | - Jianzhong Sun
- Biofuels Institute, School of the Environment and Safety Engineering, Jiangsu University, Zhenjiang, China
- * E-mail:
| | - Miao Huang
- Biofuels Institute, School of the Environment and Safety Engineering, Jiangsu University, Zhenjiang, China
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Miskovic L, Alff-Tuomala S, Soh KC, Barth D, Salusjärvi L, Pitkänen JP, Ruohonen L, Penttilä M, Hatzimanikatis V. A design-build-test cycle using modeling and experiments reveals interdependencies between upper glycolysis and xylose uptake in recombinant S. cerevisiae and improves predictive capabilities of large-scale kinetic models. BIOTECHNOLOGY FOR BIOFUELS 2017; 10:166. [PMID: 28674555 PMCID: PMC5485749 DOI: 10.1186/s13068-017-0838-5] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/06/2016] [Accepted: 06/06/2017] [Indexed: 05/28/2023]
Abstract
BACKGROUND Recent advancements in omics measurement technologies have led to an ever-increasing amount of available experimental data that necessitate systems-oriented methodologies for efficient and systematic integration of data into consistent large-scale kinetic models. These models can help us to uncover new insights into cellular physiology and also to assist in the rational design of bioreactor or fermentation processes. Optimization and Risk Analysis of Complex Living Entities (ORACLE) framework for the construction of large-scale kinetic models can be used as guidance for formulating alternative metabolic engineering strategies. RESULTS We used ORACLE in a metabolic engineering problem: improvement of the xylose uptake rate during mixed glucose-xylose consumption in a recombinant Saccharomyces cerevisiae strain. Using the data from bioreactor fermentations, we characterized network flux and concentration profiles representing possible physiological states of the analyzed strain. We then identified enzymes that could lead to improved flux through xylose transporters (XTR). For some of the identified enzymes, including hexokinase (HXK), we could not deduce if their control over XTR was positive or negative. We thus performed a follow-up experiment, and we found out that HXK2 deletion improves xylose uptake rate. The data from the performed experiments were then used to prune the kinetic models, and the predictions of the pruned population of kinetic models were in agreement with the experimental data collected on the HXK2-deficient S. cerevisiae strain. CONCLUSIONS We present a design-build-test cycle composed of modeling efforts and experiments with a glucose-xylose co-utilizing recombinant S. cerevisiae and its HXK2-deficient mutant that allowed us to uncover interdependencies between upper glycolysis and xylose uptake pathway. Through this cycle, we also obtained kinetic models with improved prediction capabilities. The present study demonstrates the potential of integrated "modeling and experiments" systems biology approaches that can be applied for diverse applications ranging from biotechnology to drug discovery.
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Affiliation(s)
- Ljubisa Miskovic
- Ecole Polytechnique Federale de Lausanne (EPFL), 1015 Lausanne, Switzerland
| | | | - Keng Cher Soh
- Ecole Polytechnique Federale de Lausanne (EPFL), 1015 Lausanne, Switzerland
| | - Dorothee Barth
- VTT Technical Research Centre of Finland Ltd, Espoo, Finland
| | | | | | - Laura Ruohonen
- VTT Technical Research Centre of Finland Ltd, Espoo, Finland
| | - Merja Penttilä
- VTT Technical Research Centre of Finland Ltd, Espoo, Finland
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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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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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Light-controlled gene expression in yeast using photocaged Cu 2. J Biotechnol 2017; 258:117-125. [PMID: 28455204 DOI: 10.1016/j.jbiotec.2017.04.032] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2016] [Revised: 04/24/2017] [Accepted: 04/24/2017] [Indexed: 11/21/2022]
Abstract
The manipulation of cellular function, such as the regulation of gene expression, is of great interest to many biotechnological applications and often achieved by the addition of small effector molecules. By combining effector molecules with photolabile protecting groups that mask their biological activity until they are activated by light, precise, yet minimally invasive, photocontrol is enabled. However, applications of this trendsetting technology are limited by the small number of established caged compound-based expression systems. Supported by computational chemistry, we used the versatile photolabile chelator DMNP-EDTA, long-established in neurobiology for photolytic Ca2+ release, to control Cu2+ release upon specific UV-A irradiation. This permits light-mediated control over the widely used Cu2+-inducible pCUP1 promoter from S. cerevisiae and thus constitutes the first example of a caged metal ion to regulate recombinant gene expression. We screened our novel DMNP-EDTA-Cu system for best induction time and expression level of eYFP with a high-throughput online monitoring system equipped with an LED array for individual illumination of every single well. Thereby, we realized a minimally invasive, easy-to-control, parallel and automated optical expression regulation via caged Cu2+ allowing temporal and quantitative control as a beneficial alternative to conventional induction via pipetting CuCl2 as effector molecule.
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Zeng WY, Tang YQ, Gou M, Sun ZY, Xia ZY, Kida K. Comparative transcriptomes reveal novel evolutionary strategies adopted by Saccharomyces cerevisiae with improved xylose utilization capability. Appl Microbiol Biotechnol 2016; 101:1753-1767. [DOI: 10.1007/s00253-016-8046-y] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/26/2016] [Revised: 11/28/2016] [Accepted: 12/01/2016] [Indexed: 10/20/2022]
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Affiliation(s)
- Tao Jin
- Iowa State University; Department of Chemical and Biological Engineering; 2114 Sweeney Hall, 618 Bissell Rd. Ames, IA 50011 USA
| | - Jieni Lian
- Iowa State University; Department of Chemical and Biological Engineering; 2114 Sweeney Hall, 618 Bissell Rd. Ames, IA 50011 USA
| | - Laura R. Jarboe
- Iowa State University; Department of Chemical and Biological Engineering; 2114 Sweeney Hall, 618 Bissell Rd. Ames, IA 50011 USA
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Li H, Shen Y, Wu M, Hou J, Jiao C, Li Z, Liu X, Bao X. Engineering a wild-type diploid Saccharomyces cerevisiae strain for second-generation bioethanol production. BIORESOUR BIOPROCESS 2016; 3:51. [PMID: 27942436 PMCID: PMC5122614 DOI: 10.1186/s40643-016-0126-4] [Citation(s) in RCA: 44] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/09/2016] [Accepted: 11/11/2016] [Indexed: 11/24/2022] Open
Abstract
Background The cost-effective production of second-generation bioethanol, which is made from lignocellulosic materials, has to face the following two problems: co-fermenting xylose with glucose and enhancing the strain’s tolerance to lignocellulosic inhibitors. Based on our previous study, the wild-type diploid Saccharomyces cerevisiae strain BSIF with robustness and good xylose metabolism genetic background was used as a chassis for constructing efficient xylose-fermenting industrial strains. The performance of the resulting strains in the fermentation of media with sugars and hydrolysates was investigated. Results The following two novel heterologous genes were integrated into the genome of the chassis cell: the mutant MGT05196N360F, which encodes a xylose-specific, glucose-insensitive transporter and is derived from the Meyerozyma guilliermondii transporter gene MGT05196, and Ru-xylA (where Ru represents the rumen), which encodes a xylose isomerase (XI) with higher activity in S. cerevisiae. Additionally, endogenous modifications were also performed, including the overproduction of the xylulokinase Xks1p and the non-oxidative PPP (pentose phosphate pathway), and the inactivation of the aldose reductase Gre3p and the alkaline phosphatase Pho13p. These rationally designed genetic modifications, combined with alternating adaptive evolutions in xylose and SECS liquor (the leach liquor of steam-exploding corn stover), resulted in a final strain, LF1, with excellent xylose fermentation and enhanced inhibitor resistance. The specific xylose consumption rate of LF1 reached as high as 1.089 g g−1 h−1 with xylose as the sole carbon source. Moreover, its highly synchronized utilization of xylose and glucose was particularly significant; 77.6% of xylose was consumed along with glucose within 12 h, and the ethanol yield was 0.475 g g−1, which is more than 93% of the theoretical yield. Additionally, LF1 performed well in fermentations with two different lignocellulosic hydrolysates. Conclusion The strain LF1 co-ferments glucose and xylose efficiently and synchronously. This result highlights the great potential of LF1 for the practical production of second-generation bioethanol. Electronic supplementary material The online version of this article (doi:10.1186/s40643-016-0126-4) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Hongxing Li
- State Key Laboratory of Microbial Technology, Shandong University, Shan Da Nan Road 27, Jinan, 250100 China.,Shandong Provincial Key Laboratory of Microbial Engineering, Qi Lu University of Technology, Jinan, 250353 China
| | - Yu Shen
- State Key Laboratory of Microbial Technology, Shandong University, Shan Da Nan Road 27, Jinan, 250100 China
| | - Meiling Wu
- State Key Laboratory of Microbial Technology, Shandong University, Shan Da Nan Road 27, Jinan, 250100 China
| | - Jin Hou
- State Key Laboratory of Microbial Technology, Shandong University, Shan Da Nan Road 27, Jinan, 250100 China
| | - Chunlei Jiao
- State Key Laboratory of Microbial Technology, Shandong University, Shan Da Nan Road 27, Jinan, 250100 China
| | - Zailu Li
- Shandong Provincial Key Laboratory of Microbial Engineering, Qi Lu University of Technology, Jinan, 250353 China
| | - Xinli Liu
- Shandong Provincial Key Laboratory of Microbial Engineering, Qi Lu University of Technology, Jinan, 250353 China
| | - Xiaoming Bao
- State Key Laboratory of Microbial Technology, Shandong University, Shan Da Nan Road 27, Jinan, 250100 China.,Shandong Provincial Key Laboratory of Microbial Engineering, Qi Lu University of Technology, Jinan, 250353 China
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Xiong X, Lian J, Yu X, Garcia-Perez M, Chen S. Engineering levoglucosan metabolic pathway in Rhodococcus jostii RHA1 for lipid production. J Ind Microbiol Biotechnol 2016; 43:1551-1560. [PMID: 27558782 DOI: 10.1007/s10295-016-1832-9] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/12/2016] [Accepted: 08/15/2016] [Indexed: 11/28/2022]
Abstract
Oleaginous strains of Rhodococcus including R. jostii RHA1 have attracted considerable attention due to their ability to accumulate triacylglycerols (TAGs), robust growth properties and genetic tractability. In this study, a novel metabolic pathway was introduced into R. jostii by heterogenous expression of the well-characterized gene, lgk encoding levoglucosan kinase from Lipomyces starkeyi YZ-215. This enables the recombinant R. jostii RHA1 to produce TAGs from the anhydrous sugar, levoglucosan, which can be generated efficiently as the major molecule from the pyrolysis of cellulose. The recombinant R. jostii RHA1 could grow on levoglucosan as the sole carbon source, and the consumption rate of levoglucosan was determined. Furthermore, expression of one more copy of lgk increased the enzymatic activity of LGK in the recombinant. However, the growth performance of the recombinant bearing two copies of lgk on levoglucosan was not improved. Although expression of lgk in the recombinants was not repressed by the glucose present in the media, glucose in the sugar mixture still affected consumption of levoglucosan. Under nitrogen limiting conditions, lipid produced from levoglucosan by the recombinant bearing lgk was up to 43.54 % of the cell dry weight, which was comparable to the content of lipid accumulated from glucose. This work demonstrated the technical feasibility of producing lipid from levoglucosan, an anhydrosugar derived from the pyrolysis of lignocellulosic materials, by the genetically modified rhodococci strains.
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Affiliation(s)
- Xiaochao Xiong
- Department of Biological Systems Engineering, Washington State University, L. J. Smith Hall, P.O. Box 646120, Pullman, WA, 99164-6120, USA
| | - Jieni Lian
- Department of Biological Systems Engineering, Washington State University, L. J. Smith Hall, P.O. Box 646120, Pullman, WA, 99164-6120, USA.,Department of Chemical and Biological Engineering, Iowa State University, Ames, IA, 50011, USA
| | - Xiaochen Yu
- Department of Biological Systems Engineering, Washington State University, L. J. Smith Hall, P.O. Box 646120, Pullman, WA, 99164-6120, USA.,Department of Biochemistry, Biophysics, and Molecular Biology, Iowa State University, Ames, IA, 50011, USA
| | - Manuel Garcia-Perez
- Department of Biological Systems Engineering, Washington State University, L. J. Smith Hall, P.O. Box 646120, Pullman, WA, 99164-6120, USA
| | - Shulin Chen
- Department of Biological Systems Engineering, Washington State University, L. J. Smith Hall, P.O. Box 646120, Pullman, WA, 99164-6120, USA.
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Bamba T, Hasunuma T, Kondo A. Disruption of PHO13 improves ethanol production via the xylose isomerase pathway. AMB Express 2016; 6:4. [PMID: 26769491 PMCID: PMC4713403 DOI: 10.1186/s13568-015-0175-7] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/15/2015] [Accepted: 12/11/2015] [Indexed: 01/08/2023] Open
Abstract
Xylose is the second most abundant sugar in lignocellulosic materials and can be converted to ethanol by recombinant Saccharomyces cerevisiae yeast strains expressing heterologous genes involved in xylose assimilation pathways. Recent research demonstrated that disruption of the alkaline phosphatase gene, PHO13, enhances ethanol production from xylose by a strain expressing the xylose reductase (XR) and xylitol dehydrogenase (XDH) genes; however, the yield of ethanol is poor. In this study, PHO13 was disrupted in a recombinant strain harboring multiple copies of the xylose isomerase (XI) gene derived from Orpinomyces sp., coupled with overexpression of the endogenous xylulokinase (XK) gene and disruption of GRE3, which encodes aldose reductase. The resulting YΔGP/XK/XI strain consumed 2.08 g/L/h of xylose and produced 0.88 g/L/h of volumetric ethanol, for an 86.8 % theoretical ethanol yield, and only YΔGP/XK/XI demonstrated increase in cell concentration. Transcriptome analysis indicated that expression of genes involved in the pentose phosphate pathway (GND1, SOL3, TAL1, RKI1, and TKL1) and TCA cycle and respiratory chain (NDE1, ACO1, ACO2, SDH2, IDH1, IDH2, ATP7, ATP19, SDH4, SDH3, CMC2, and ATP15) was upregulated in the YΔGP/XK/XI strain. And the expression levels of 125 cell cycle genes were changed by deletion of PHO13.
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Moysés DN, Reis VCB, de Almeida JRM, de Moraes LMP, Torres FAG. Xylose Fermentation by Saccharomyces cerevisiae: Challenges and Prospects. Int J Mol Sci 2016; 17:207. [PMID: 26927067 PMCID: PMC4813126 DOI: 10.3390/ijms17030207] [Citation(s) in RCA: 138] [Impact Index Per Article: 17.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2015] [Revised: 01/23/2016] [Accepted: 01/27/2016] [Indexed: 12/17/2022] Open
Abstract
Many years have passed since the first genetically modified Saccharomyces cerevisiae strains capable of fermenting xylose were obtained with the promise of an environmentally sustainable solution for the conversion of the abundant lignocellulosic biomass to ethanol. Several challenges emerged from these first experiences, most of them related to solving redox imbalances, discovering new pathways for xylose utilization, modulation of the expression of genes of the non-oxidative pentose phosphate pathway, and reduction of xylitol formation. Strategies on evolutionary engineering were used to improve fermentation kinetics, but the resulting strains were still far from industrial application. Lignocellulosic hydrolysates proved to have different inhibitors derived from lignin and sugar degradation, along with significant amounts of acetic acid, intrinsically related with biomass deconstruction. This, associated with pH, temperature, high ethanol, and other stress fluctuations presented on large scale fermentations led the search for yeasts with more robust backgrounds, like industrial strains, as engineering targets. Some promising yeasts were obtained both from studies of stress tolerance genes and adaptation on hydrolysates. Since fermentation times on mixed-substrate hydrolysates were still not cost-effective, the more selective search for new or engineered sugar transporters for xylose are still the focus of many recent studies. These challenges, as well as under-appreciated process strategies, will be discussed in this review.
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Affiliation(s)
- Danuza Nogueira Moysés
- Departamento de Biologia Celular, Universidade de Brasília, Brasília, DF 70910-900, Brazil.
- Petrobras Research and Development Center, Biotechnology Management, Rio de Janeiro, RJ 21941-915, Brazil.
| | | | - João Ricardo Moreira de Almeida
- Embrapa Agroenergia, Laboratório de Genética e Biotecnologia, Parque Estação Biológica s/n, Av. W3 Norte, Brasília, DF 70770-901, Brazil.
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Shalley Sharma, Sonia Sharma, Surender Singh, Lata, Anju Arora. Improving Yeast Strains for Pentose Hexose Co-fermentation: Successes and Hurdles. SPRINGER PROCEEDINGS IN ENERGY 2016. [DOI: 10.1007/978-81-322-2773-1_3] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
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40
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Chu L, Zan X, Tang X, Zhao L, Chen H, Chen YQ, Chen W, Song Y. The role of a xylose isomerase pathway in the conversion of xylose to lipid in Mucor circinelloides. RSC Adv 2016. [DOI: 10.1039/c6ra12379a] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
The xylose isomerase (XI) pathway, which converts xylose in lignocellulosic materials into intermediate metabolites, is characterized for the first time in M. circinelloides.
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Affiliation(s)
- Linfang Chu
- State Key Laboratory of Food Science and Technology
- School of Food Science and Technology
- Jiangnan University
- Wuxi
- P. R. China
| | - Xinyi Zan
- State Key Laboratory of Food Science and Technology
- School of Food Science and Technology
- Jiangnan University
- Wuxi
- P. R. China
| | - Xin Tang
- State Key Laboratory of Food Science and Technology
- School of Food Science and Technology
- Jiangnan University
- Wuxi
- P. R. China
| | - Lina Zhao
- State Key Laboratory of Food Science and Technology
- School of Food Science and Technology
- Jiangnan University
- Wuxi
- P. R. China
| | - Haiqin Chen
- State Key Laboratory of Food Science and Technology
- School of Food Science and Technology
- Jiangnan University
- Wuxi
- P. R. China
| | - Yong Q. Chen
- State Key Laboratory of Food Science and Technology
- School of Food Science and Technology
- Jiangnan University
- Wuxi
- P. R. China
| | - Wei Chen
- State Key Laboratory of Food Science and Technology
- School of Food Science and Technology
- Jiangnan University
- Wuxi
- P. R. China
| | - Yuanda Song
- State Key Laboratory of Food Science and Technology
- School of Food Science and Technology
- Jiangnan University
- Wuxi
- P. R. China
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41
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Lee SM, Jellison T, Alper HS. Bioprospecting and evolving alternative xylose and arabinose pathway enzymes for use in Saccharomyces cerevisiae. Appl Microbiol Biotechnol 2015; 100:2487-98. [DOI: 10.1007/s00253-015-7211-z] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/02/2015] [Revised: 11/05/2015] [Accepted: 12/01/2015] [Indexed: 10/22/2022]
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42
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Qi X, Zha J, Liu GG, Zhang W, Li BZ, Yuan YJ. Heterologous xylose isomerase pathway and evolutionary engineering improve xylose utilization in Saccharomyces cerevisiae. Front Microbiol 2015; 6:1165. [PMID: 26539187 PMCID: PMC4612707 DOI: 10.3389/fmicb.2015.01165] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/26/2015] [Accepted: 10/08/2015] [Indexed: 12/24/2022] Open
Abstract
Xylose utilization is one key issue for the bioconversion of lignocelluloses. It is a promising approach to engineering heterologous pathway for xylose utilization in Saccharomyces cerevisiae. Here, we constructed a xylose-fermenting yeast SyBE001 through combinatorial fine-tuning the expression of XylA and endogenous XKS1. Additional overexpression of genes RKI1, RPE1, TKL1, and TAL1 in the non-oxidative pentose phosphate pathway (PPP) in SyBE001 increased the xylose consumption rate by 1.19-fold. By repetitive adaptation, the xylose utilization rate was further increased by ∼10-fold in the resultant strain SyBE003. Gene expression analysis identified a variety of genes with significantly changed expression in the PPP, glycolysis and the tricarboxylic acid cycle in SyBE003.
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Affiliation(s)
- Xin Qi
- Key Laboratory of Systems Bioengineering, Ministry of Education, Tianjin University Tianjin, China ; SynBio Research Platform, Collaborative Innovation Center of Chemical Science and Engineering (Tianjin), School of Chemical Engineering and Technology, Tianjin University Tianjin, China
| | - Jian Zha
- Key Laboratory of Systems Bioengineering, Ministry of Education, Tianjin University Tianjin, China ; SynBio Research Platform, Collaborative Innovation Center of Chemical Science and Engineering (Tianjin), School of Chemical Engineering and Technology, Tianjin University Tianjin, China
| | - Gao-Gang Liu
- Key Laboratory of Systems Bioengineering, Ministry of Education, Tianjin University Tianjin, China ; SynBio Research Platform, Collaborative Innovation Center of Chemical Science and Engineering (Tianjin), School of Chemical Engineering and Technology, Tianjin University Tianjin, China
| | - Weiwen Zhang
- Key Laboratory of Systems Bioengineering, Ministry of Education, Tianjin University Tianjin, China ; SynBio Research Platform, Collaborative Innovation Center of Chemical Science and Engineering (Tianjin), School of Chemical Engineering and Technology, Tianjin University Tianjin, China
| | - Bing-Zhi Li
- Key Laboratory of Systems Bioengineering, Ministry of Education, Tianjin University Tianjin, China ; SynBio Research Platform, Collaborative Innovation Center of Chemical Science and Engineering (Tianjin), School of Chemical Engineering and Technology, Tianjin University Tianjin, China
| | - Ying-Jin Yuan
- Key Laboratory of Systems Bioengineering, Ministry of Education, Tianjin University Tianjin, China ; SynBio Research Platform, Collaborative Innovation Center of Chemical Science and Engineering (Tianjin), School of Chemical Engineering and Technology, Tianjin University Tianjin, China
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43
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Park JB, Kim JS, Jang SW, Hong E, Ha SJ. The Application of Thermotolerant Yeast Kluyveromyces marxianus as a Potential Industrial Workhorse for Biofuel Production. ACTA ACUST UNITED AC 2015. [DOI: 10.7841/ksbbj.2015.30.3.125] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
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44
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Lactic acid production from xylose by engineered Saccharomyces cerevisiae without PDC or ADH deletion. Appl Microbiol Biotechnol 2015; 99:8023-33. [DOI: 10.1007/s00253-015-6701-3] [Citation(s) in RCA: 38] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/25/2015] [Revised: 05/11/2015] [Accepted: 05/15/2015] [Indexed: 10/23/2022]
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45
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Lee SM, Jellison T, Alper HS. Xylan catabolism is improved by blending bioprospecting and metabolic pathway engineering in Saccharomyces cerevisiae. Biotechnol J 2015; 10:575-83. [PMID: 25651533 DOI: 10.1002/biot.201400622] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/09/2014] [Revised: 01/09/2015] [Accepted: 02/03/2015] [Indexed: 11/09/2022]
Abstract
Complete utilization of all available carbon sources in lignocellulosic biomass still remains a challenge in engineering Saccharomyces cerevisiae. Even with efficient heterologous xylose catabolic pathways, S. cerevisiae is unable to utilize xylose in lignocellulosic biomass unless xylan is depolymerized to xylose. Here we demonstrate that a blended bioprospecting approach along with pathway engineering and evolutionary engineering can be used to improve xylan catabolism in S. cerevisiae. Specifically, we perform whole genome sequencing-based bioprospecting of a strain with remarkable pentose catabolic potential that we isolated and named Ustilago bevomyces. The heterologous expression of xylan catabolic genes enabled S. cerevisiae to grow on xylan as a single carbon source in minimal medium. A combination of bioprospecting and metabolic pathway evolution demonstrated that the xylan catabolic pathway could be further improved. Ultimately, engineering efforts were able to achieve xylan conversion into ethanol of up to 0.22 g/L on minimal medium compositions with xylan. This pathway provides a novel starting point for improving lignocellulosic conversion by yeast.
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Affiliation(s)
- Sun-Mi Lee
- McKetta Department of Chemical Engineering, The University of Texas at Austin, Austin, Texas; Clean Energy Research Center, Korea Institute of Science and Technology, Seoul, Korea
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46
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Hughes SR, Cox EJ, Bang SS, Pinkelman RJ, López-Núñez JC, Saha BC, Qureshi N, Gibbons WR, Fry MR, Moser BR, Bischoff KM, Liu S, Sterner DE, Butt TR, Riedmuller SB, Jones MA, Riaño-Herrera NM. Process for Assembly and Transformation into Saccharomyces cerevisiae of a Synthetic Yeast Artificial Chromosome Containing a Multigene Cassette to Express Enzymes That Enhance Xylose Utilization Designed for an Automated Platform. ACTA ACUST UNITED AC 2015; 20:621-35. [PMID: 25720598 DOI: 10.1177/2211068215573188] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2014] [Indexed: 01/26/2023]
Abstract
A yeast artificial chromosome (YAC) containing a multigene cassette for expression of enzymes that enhance xylose utilization (xylose isomerase [XI] and xylulokinase [XKS]) was constructed and transformed into Saccharomyces cerevisiae to demonstrate feasibility as a stable protein expression system in yeast and to design an assembly process suitable for an automated platform. Expression of XI and XKS from the YAC was confirmed by Western blot and PCR analyses. The recombinant and wild-type strains showed similar growth on plates containing hexose sugars, but only recombinant grew on D-xylose and L-arabinose plates. In glucose fermentation, doubling time (4.6 h) and ethanol yield (0.44 g ethanol/g glucose) of recombinant were comparable to wild type (4.9 h and 0.44 g/g). In whole-corn hydrolysate, ethanol yield (0.55 g ethanol/g [glucose + xylose]) and xylose utilization (38%) for recombinant were higher than for wild type (0.47 g/g and 12%). In hydrolysate from spent coffee grounds, yield was 0.46 g ethanol/g (glucose + xylose), and xylose utilization was 93% for recombinant. These results indicate introducing a YAC expressing XI and XKS enhanced xylose utilization without affecting integrity of the host strain, and the process provides a potential platform for automated synthesis of a YAC for expression of multiple optimized genes to improve yeast strains.
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Affiliation(s)
- Stephen R Hughes
- United States Department of Agriculture (USDA), Agricultural Research Service (ARS), National Center for Agricultural Utilization Research (NCAUR), Renewable Product Technology Research Unit, Peoria, IL, USA
| | - Elby J Cox
- United States Department of Agriculture (USDA), Agricultural Research Service (ARS), National Center for Agricultural Utilization Research (NCAUR), Renewable Product Technology Research Unit, Peoria, IL, USA Department of Chemistry and Biochemistry, Bradley University, Peoria, IL, USA
| | - Sookie S Bang
- South Dakota School of Mines & Technology, Chemical and Biological Engineering, Rapid City, SD, USA
| | - Rebecca J Pinkelman
- South Dakota School of Mines & Technology, Chemical and Biological Engineering, Rapid City, SD, USA
| | - Juan Carlos López-Núñez
- National Coffee Research Centre (Cenicafe), National Federation of Coffee Growers of Colombia (FNC), Manizales, Caldas, Colombia
| | - Badal C Saha
- USDA, ARS, NCAUR, Bioenergy Research Unit, Peoria, IL, USA
| | - Nasib Qureshi
- USDA, ARS, NCAUR, Bioenergy Research Unit, Peoria, IL, USA
| | - William R Gibbons
- Department of Biology and Microbiology, South Dakota State University, Brookings, SD, USA
| | - Michelle R Fry
- Department of Chemistry and Biochemistry, Bradley University, Peoria, IL, USA
| | - Bryan R Moser
- USDA, ARS, NCAUR, Bio-Oils Research Unit, Peoria, IL, USA
| | - Kenneth M Bischoff
- United States Department of Agriculture (USDA), Agricultural Research Service (ARS), National Center for Agricultural Utilization Research (NCAUR), Renewable Product Technology Research Unit, Peoria, IL, USA
| | - Siqing Liu
- United States Department of Agriculture (USDA), Agricultural Research Service (ARS), National Center for Agricultural Utilization Research (NCAUR), Renewable Product Technology Research Unit, Peoria, IL, USA
| | | | | | | | - Marjorie A Jones
- Department of Chemistry, Illinois State University, Normal, IL, USA
| | - Néstor M Riaño-Herrera
- National Coffee Research Centre (Cenicafe), National Federation of Coffee Growers of Colombia (FNC), Manizales, Caldas, Colombia
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47
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Wasylenko TM, Stephanopoulos G. Metabolomic and (13)C-metabolic flux analysis of a xylose-consuming Saccharomyces cerevisiae strain expressing xylose isomerase. Biotechnol Bioeng 2014; 112:470-83. [PMID: 25311863 DOI: 10.1002/bit.25447] [Citation(s) in RCA: 57] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/29/2014] [Revised: 08/11/2014] [Accepted: 08/27/2014] [Indexed: 11/09/2022]
Abstract
Over the past two decades, significant progress has been made in the engineering of xylose-consuming Saccharomyces cerevisiae strains for production of lignocellulosic biofuels. However, the ethanol productivities achieved on xylose are still significantly lower than those observed on glucose for reasons that are not well understood. We have undertaken an analysis of central carbon metabolite pool sizes and metabolic fluxes on glucose and on xylose under aerobic and anaerobic conditions in a strain capable of rapid xylose assimilation via xylose isomerase in order to investigate factors that may limit the rate of xylose fermentation. We find that during xylose utilization the flux through the non-oxidative Pentose Phosphate Pathway (PPP) is high but the flux through the oxidative PPP is low, highlighting an advantage of the strain employed in this study. Furthermore, xylose fails to elicit the full carbon catabolite repression response that is characteristic of glucose fermentation in S. cerevisiae. We present indirect evidence that the incomplete activation of the fermentation program on xylose results in a bottleneck in lower glycolysis, leading to inefficient re-oxidation of NADH produced in glycolysis.
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Affiliation(s)
- Thomas M Wasylenko
- Department of Chemical Engineering, Massachusetts Institute of Technology, Cambridge, 02139, Massachussetts
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48
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Employing a combinatorial expression approach to characterize xylose utilization in Saccharomyces cerevisiae. Metab Eng 2014; 25:20-9. [DOI: 10.1016/j.ymben.2014.06.002] [Citation(s) in RCA: 62] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/08/2014] [Revised: 05/07/2014] [Accepted: 06/04/2014] [Indexed: 12/24/2022]
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49
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Steensels J, Snoek T, Meersman E, Nicolino MP, Voordeckers K, Verstrepen KJ. Improving industrial yeast strains: exploiting natural and artificial diversity. FEMS Microbiol Rev 2014; 38:947-95. [PMID: 24724938 PMCID: PMC4293462 DOI: 10.1111/1574-6976.12073] [Citation(s) in RCA: 257] [Impact Index Per Article: 25.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/01/2013] [Revised: 01/31/2014] [Accepted: 04/02/2014] [Indexed: 12/23/2022] Open
Abstract
Yeasts have been used for thousands of years to make fermented foods and beverages, such as beer, wine, sake, and bread. However, the choice for a particular yeast strain or species for a specific industrial application is often based on historical, rather than scientific grounds. Moreover, new biotechnological yeast applications, such as the production of second-generation biofuels, confront yeast with environments and challenges that differ from those encountered in traditional food fermentations. Together, this implies that there are interesting opportunities to isolate or generate yeast variants that perform better than the currently used strains. Here, we discuss the different strategies of strain selection and improvement available for both conventional and nonconventional yeasts. Exploiting the existing natural diversity and using techniques such as mutagenesis, protoplast fusion, breeding, genome shuffling and directed evolution to generate artificial diversity, or the use of genetic modification strategies to alter traits in a more targeted way, have led to the selection of superior industrial yeasts. Furthermore, recent technological advances allowed the development of high-throughput techniques, such as 'global transcription machinery engineering' (gTME), to induce genetic variation, providing a new source of yeast genetic diversity.
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Affiliation(s)
- Jan Steensels
- Laboratory for Genetics and Genomics, Centre of Microbial and Plant Genetics (CMPG), KU LeuvenLeuven, Belgium
- Laboratory for Systems Biology, VIBLeuven, Belgium
| | - Tim Snoek
- Laboratory for Genetics and Genomics, Centre of Microbial and Plant Genetics (CMPG), KU LeuvenLeuven, Belgium
- Laboratory for Systems Biology, VIBLeuven, Belgium
| | - Esther Meersman
- Laboratory for Genetics and Genomics, Centre of Microbial and Plant Genetics (CMPG), KU LeuvenLeuven, Belgium
- Laboratory for Systems Biology, VIBLeuven, Belgium
| | - Martina Picca Nicolino
- Laboratory for Genetics and Genomics, Centre of Microbial and Plant Genetics (CMPG), KU LeuvenLeuven, Belgium
- Laboratory for Systems Biology, VIBLeuven, Belgium
| | - Karin Voordeckers
- Laboratory for Genetics and Genomics, Centre of Microbial and Plant Genetics (CMPG), KU LeuvenLeuven, Belgium
- Laboratory for Systems Biology, VIBLeuven, Belgium
| | - Kevin J Verstrepen
- Laboratory for Genetics and Genomics, Centre of Microbial and Plant Genetics (CMPG), KU LeuvenLeuven, Belgium
- Laboratory for Systems Biology, VIBLeuven, Belgium
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50
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Xylose and xylose/glucose co-fermentation by recombinant Saccharomyces cerevisiae strains expressing individual hexose transporters. Enzyme Microb Technol 2014; 63:13-20. [DOI: 10.1016/j.enzmictec.2014.05.003] [Citation(s) in RCA: 53] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/19/2014] [Revised: 05/08/2014] [Accepted: 05/09/2014] [Indexed: 01/16/2023]
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