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Regmi P, Knesebeck M, Boles E, Weuster-Botz D, Oreb M. A comparative analysis of NADPH supply strategies in Saccharomyces cerevisiae: Production of d-xylitol from d-xylose as a case study. Metab Eng Commun 2024; 19:e00245. [PMID: 39072283 PMCID: PMC11283233 DOI: 10.1016/j.mec.2024.e00245] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/29/2024] [Revised: 07/04/2024] [Accepted: 07/04/2024] [Indexed: 07/30/2024] Open
Abstract
Enhancing the supply of the redox cofactor NADPH in metabolically engineered cells is a critical target for optimizing the synthesis of many product classes, such as fatty acids or terpenoids. In S. cerevisiae, several successful approaches have been developed in different experimental contexts. However, their systematic comparison has not been reported. Here, we established the reduction of xylose to xylitol by an NADPH-dependent xylose reductase as a model reaction to compare the efficacy of different NADPH supply strategies in the course of a batch fermentation, in which glucose and ethanol are sequentially used as carbon sources and redox donors. We show that strains overexpressing the glucose-6-phosphate dehydrogenase Zwf1 perform best, producing up to 16.9 g L-1 xylitol from 20 g L-1 xylose in stirred tank bioreactors. The beneficial effect of increased Zwf1 activity is especially pronounced during the ethanol consumption phase. The same notion applies to the deletion of the aldehyde dehydrogenase ALD6 gene, albeit at a quantitatively lower level. Reduced expression of the phosphoglucose isomerase Pgi1 and heterologous expression of the NADP+-dependent glyceraldehyde-3-phosphate dehydrogenase Gdp1 from Kluyveromyces lactis acted synergistically with ZWF1 overexpression in the presence of glucose, but had a detrimental effect after the diauxic shift. Expression of the mitochondrial NADH kinase Pos5 in the cytosol likewise improved the production of xylitol only on glucose, but not in combination with enhanced Zwf1 activity. To demonstrate the generalizability of our observations, we show that the most promising strategies - ZWF1 overexpression and deletion of ALD6 - also improve the production of l-galactonate from d-galacturonic acid. Therefore, we expect that these findings will provide valuable guidelines for engineering not only the production of xylitol but also of diverse other pathways that require NADPH.
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Affiliation(s)
- Priti Regmi
- Goethe University Frankfurt, Faculty of Biological Sciences, Institute of Molecular Biosciences, Max-von-Laue Straße 9, 60438, Frankfurt am Main, Germany
| | - Melanie Knesebeck
- Technical University of Munich, Chair of Biochemical Engineering, Boltzmannstr. 15, 85748, Garching, Germany
| | - Eckhard Boles
- Goethe University Frankfurt, Faculty of Biological Sciences, Institute of Molecular Biosciences, Max-von-Laue Straße 9, 60438, Frankfurt am Main, Germany
| | - Dirk Weuster-Botz
- Technical University of Munich, Chair of Biochemical Engineering, Boltzmannstr. 15, 85748, Garching, Germany
| | - Mislav Oreb
- Goethe University Frankfurt, Faculty of Biological Sciences, Institute of Molecular Biosciences, Max-von-Laue Straße 9, 60438, Frankfurt am Main, Germany
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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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Qiu Y, Liu W, Wu M, Bao H, Sun X, Dou Q, Jia H, Liu W, Shen Y. Construction of an alternative NADPH regeneration pathway improves ethanol production in Saccharomyces cerevisiae with xylose metabolic pathway. Synth Syst Biotechnol 2024; 9:269-276. [PMID: 38469586 PMCID: PMC10926300 DOI: 10.1016/j.synbio.2024.02.004] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2023] [Revised: 02/05/2024] [Accepted: 02/19/2024] [Indexed: 03/13/2024] Open
Abstract
Full conversion of glucose and xylose from lignocellulosic hydrolysates is required for obtaining a high ethanol yield. However, glucose and xylose share flux in the pentose phosphate pathway (PPP) and glycolysis pathway (EMP), with glucose having a competitive advantage in the shared metabolic pathways. In this work, we knocked down ZWF1 to preclude glucose from entering the PPP. This reduced the [NADPH] level and disturbed growth on both glucose or xylose, confirming that the oxidative PPP, which begins with Zwf1p and ultimately leads to CO2 production, is the primary source of NADPH in both glucose and xylose. Upon glucose depletion, gluconeogenesis is necessary to generate glucose-6-phosphate, the substrate of Zwf1p. We re-established the NADPH regeneration pathway by replacing the endogenous NAD+-dependent glyceraldehyde-3-phosphate dehydrogenase (GAPDH) gene TDH3 with heterogenous NADP + -GAPDH genes GDH, gapB, and GDP1. Among the resulting strains, the strain BZP1 (zwf1Δ, tdh3::GDP1) exhibited a similar xylose consumption rate before glucose depletion, but a 1.6-fold increased xylose consumption rate following glucose depletion compared to the original strain BSGX001, and the ethanol yield for total consumed sugars of BZP1 was 13.5% higher than BSGX001. This suggested that using the EMP instead of PPP to generate NADPH reduces the wasteful metabolic cycle and excess CO2 release from oxidative PPP. Furthermore, we used a copper-repressing promoter to modulate the expression of ZWF1 and optimize the timing of turning off the ZWF1, therefore, to determine the competitive equilibrium between glucose-xylose co-metabolism. This strategy allowed fast growth in the early stage of fermentation and low waste in the following stages of fermentation.
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Affiliation(s)
- Yali Qiu
- State Key Laboratory of Microbial Technology, Institute of Microbial Technology, Shandong University, Qingdao, 266237, China
| | - Wei Liu
- State Key Laboratory of Microbial Technology, Institute of Microbial Technology, Shandong University, Qingdao, 266237, China
| | - Meiling Wu
- Advanced Medical Research Institute, Shandong University, Jinan, 250012, China
| | - Haodong Bao
- State Key Laboratory of Microbial Technology, Institute of Microbial Technology, Shandong University, Qingdao, 266237, China
| | - Xinhua Sun
- State Key Laboratory of Microbial Technology, Institute of Microbial Technology, Shandong University, Qingdao, 266237, China
| | - Qin Dou
- State Key Laboratory of Microbial Technology, Institute of Microbial Technology, Shandong University, Qingdao, 266237, China
| | - Hongying Jia
- State Key Laboratory of Microbial Technology, Institute of Microbial Technology, Shandong University, Qingdao, 266237, China
| | - Weifeng Liu
- State Key Laboratory of Microbial Technology, Institute of Microbial Technology, Shandong University, Qingdao, 266237, China
| | - Yu Shen
- State Key Laboratory of Microbial Technology, Institute of Microbial Technology, Shandong University, Qingdao, 266237, China
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Zhang C, Wu J, Sun Q, Ding S, Tao H, He Y, Qiu H, Shu B, Zhu D, Zhu H, Hong K. De novo production of bioactive sesterterpenoid ophiobolins in Saccharomyces cerevisiae cell factories. Microb Cell Fact 2024; 23:129. [PMID: 38711040 DOI: 10.1186/s12934-024-02406-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/15/2024] [Accepted: 04/25/2024] [Indexed: 05/08/2024] Open
Abstract
BACKGROUND Sesterterpenoids are rare species among the terpenoids family. Ophiobolins are sesterterpenes with a 5-8-5 tricyclic skeleton. The oxidized ophiobolins exhibit significant cytotoxic activity and potential medicinal value. There is an urgent need for large amounts of ophiobolins supplication for drug development. The synthetic biology approach has been successfully employed in lots of terpene compound production and inspired us to develop a cell factory for ophiobolin biosynthesis. RESULTS We developed a systematic metabolic engineering strategy to construct an ophiobolin biosynthesis chassis based on Saccharomyces cerevisiae. The whole-cell biotransformation methods were further combined with metabolic engineering to enhance the expression of key ophiobolin biosynthetic genes and improve the supply of precursors and cofactors. A high yield of 5.1 g/L of ophiobolin F was reached using ethanol and fatty acids as substrates. To accumulate oxidized ophiobolins, we optimized the sources and expression conditions for P450-CPR and alleviated the toxicity of bioactive compounds to cells through PDR engineering. We unexpectedly obtained a novel ophiobolin intermediate with potent cytotoxicity, 5-hydroxy-21-formyl-ophiobolin F, and the known bioactive compound ophiobolin U. Finally, we achieved the ophiobolin U titer of 128.9 mg/L. CONCLUSIONS We established efficient cell factories based on S. cerevisiae, enabling de novo biosynthesis of the ophiobolin skeleton ophiobolin F and oxidized ophiobolins derivatives. This work has filled the gap in the heterologous biosynthesis of sesterterpenoids in S. cerevisiae and provided valuable solutions for new drug development based on sesterterpenoids.
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Affiliation(s)
- Caizhe Zhang
- Department of Radiation and Medical Oncology, Key Laboratory of Combinatorial Biosynthesis and Drug Discovery, School of Pharmaceutical Sciences, Zhongnan Hospital, Ministry of Education, Wuhan University, Wuhan, 430071, China
| | - Jun Wu
- Department of Radiation and Medical Oncology, Key Laboratory of Combinatorial Biosynthesis and Drug Discovery, School of Pharmaceutical Sciences, Zhongnan Hospital, Ministry of Education, Wuhan University, Wuhan, 430071, China
| | - Qing Sun
- Department of Radiation and Medical Oncology, Key Laboratory of Combinatorial Biosynthesis and Drug Discovery, School of Pharmaceutical Sciences, Zhongnan Hospital, Ministry of Education, Wuhan University, Wuhan, 430071, China
| | - Shuaishuai Ding
- Department of Radiation and Medical Oncology, Key Laboratory of Combinatorial Biosynthesis and Drug Discovery, School of Pharmaceutical Sciences, Zhongnan Hospital, Ministry of Education, Wuhan University, Wuhan, 430071, China
| | - Hua Tao
- Department of Radiation and Medical Oncology, Key Laboratory of Combinatorial Biosynthesis and Drug Discovery, School of Pharmaceutical Sciences, Zhongnan Hospital, Ministry of Education, Wuhan University, Wuhan, 430071, China
| | - Yuhua He
- Department of Radiation and Medical Oncology, Key Laboratory of Combinatorial Biosynthesis and Drug Discovery, School of Pharmaceutical Sciences, Zhongnan Hospital, Ministry of Education, Wuhan University, Wuhan, 430071, China
| | - Hui Qiu
- Department of Radiation and Medical Oncology, Key Laboratory of Combinatorial Biosynthesis and Drug Discovery, School of Pharmaceutical Sciences, Zhongnan Hospital, Ministry of Education, Wuhan University, Wuhan, 430071, China
| | - Bei Shu
- Department of Radiation and Medical Oncology, Key Laboratory of Combinatorial Biosynthesis and Drug Discovery, School of Pharmaceutical Sciences, Zhongnan Hospital, Ministry of Education, Wuhan University, Wuhan, 430071, China
| | - Dongqing Zhu
- Department of Radiation and Medical Oncology, Key Laboratory of Combinatorial Biosynthesis and Drug Discovery, School of Pharmaceutical Sciences, Zhongnan Hospital, Ministry of Education, Wuhan University, Wuhan, 430071, China
| | - Hengcheng Zhu
- Department of Urology, Renmin Hospital of Wuhan University, No. 238 Jie-Fang Avenue, Wuhan, 430060, China
| | - Kui Hong
- Department of Radiation and Medical Oncology, Key Laboratory of Combinatorial Biosynthesis and Drug Discovery, School of Pharmaceutical Sciences, Zhongnan Hospital, Ministry of Education, Wuhan University, Wuhan, 430071, China.
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5
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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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Bolubaid M, Özdemir A, Dertli E, Alamoudi M, Taylan O, Karaboğa D, Yılmaz MT, Şahin E. Optimization of asymmetric bioreduction conditions of 1-(thiophen-2-yl)ethanone by Weissella cibaria N9 using a desirability function-embedded face-centered optimization model. Prep Biochem Biotechnol 2023; 53:1254-1262. [PMID: 36876855 DOI: 10.1080/10826068.2023.2185898] [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] [Indexed: 03/07/2023]
Abstract
Prochiral ketones can be effectively bio-reduced to chiral secondary alcohols by whole-cell biocatalysts, which are possible useful precursors to synthesize physiologically active chemicals and natural products. When whole-cell biocatalysts strains are used, bioreduction process can be influenced by various cultural factors, and it is vital to optimize these factors that affect selectivity, conversion rate, and yield. In this study, Weissella cibaria N9 was used as whole-cell biocatalyst for bioreduction of 1-(thiophen-2-yl)ethanone, and cultural design factors were optimized using a desirability function-embedded face-centered optimization model. For this, effects of pH (4.5-5.5-6.5, x1), (2) temperature (25-30-35 °C, x2), (3) incubation period (24-48-72 h, x3), and (4) agitation speed (100-150-200 rpm, x4) on two response variables; (1) ee (%) and (2) cr (%) were tested. Next, desirability function-embedded face-centered optimization model revealed that a pH of 6.43, a temperature of 26.04 °C, an incubation period of 52.41 h, and an agitation speed of 150 rpm were the optimum levels and the estimated ee and cr responses were 99.31% and 98.16%, respectively. Importantly, the actual experimental ee and cr responses were similar to the estimated values indicating the capability of the offered desirability function-embedded face-centered optimization model when using the optimum cultural conditions.
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Affiliation(s)
- Mohammed Bolubaid
- Department of Industrial Engineering, Faculty of Engineering, King Abdulaziz University, Jeddah, Saudi Arabia
| | - Akın Özdemir
- Department of Industrial Engineering, Faculty of Engineering, Ondokuz Mayıs University, Samsun, Türkiye
| | - Enes Dertli
- Food Engineering Department, Chemical and Metallurgical Engineering Faculty, Yildiz Technical University, Istanbul, Türkiye
| | - Mohammed Alamoudi
- Department of Industrial Engineering, Faculty of Engineering, King Abdulaziz University, Jeddah, Saudi Arabia
| | - Osman Taylan
- Department of Industrial Engineering, Faculty of Engineering, King Abdulaziz University, Jeddah, Saudi Arabia
| | - Derviş Karaboğa
- Computer Engineering Department, Engineering Faculty, Erciyes University, Kayseri, Türkiye
| | - Mustafa Tahsin Yılmaz
- Department of Industrial Engineering, Faculty of Engineering, King Abdulaziz University, Jeddah, Saudi Arabia
| | - Engin Şahin
- Department of Nutrition and Dietetics, Faculty of Health Sciences, Bayburt University, Bayburt, Turkiye
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7
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Pham NN, Chang CW, Chang YH, Tu Y, Chou JY, Wang HY, Hu YC. Rational genome and metabolic engineering of Candida viswanathii by split CRISPR to produce hundred grams of dodecanedioic acid. Metab Eng 2023; 77:76-88. [PMID: 36948241 DOI: 10.1016/j.ymben.2023.03.007] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/09/2022] [Revised: 01/29/2023] [Accepted: 03/14/2023] [Indexed: 03/24/2023]
Abstract
Candida viswanathii is a promising cell factory for producing dodecanedioic acid (DDA) and other long chain dicarboxylic acids. However, metabolic engineering of C. viswanathii is difficult partly due to the lack of synthetic biology toolkits. Here we developed CRISPR-based approaches for rational genome and metabolic engineering of C. viswanathii. We first optimized the CRISPR system and protocol to promote the homozygous gene integration efficiency to >60%. We also designed a split CRISPR system for one-step integration of multiple genes into C. viswanathii. We uncovered that co-expression of CYP52A19, CPRb and FAO2 that catalyze different steps in the biotransformation enhances DDA production and abolishes accumulation of intermediates. We also unveiled that co-expression of additional enzyme POS5 further promotes DDA production and augments cell growth. We harnessed the split CRISPR system to co-integrate these 4 genes (13.6 kb) into C. viswanathii and generated a stable strain that doubles the DDA titer (224 g/L), molar conversion (83%) and productivity (1.87 g/L/h) when compared with the parent strain. This study altogether identifies appropriate enzymes/promoters to augment dodecane conversion to DDA and implicates the potential of split CRISPR system for metabolic engineering of C. viswanathii.
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Affiliation(s)
- Nam Ngoc Pham
- Department of Chemical Engineering, National Tsing Hua University, Hsinchu, Taiwan
| | - Chin-Wei Chang
- Department of Chemical Engineering, National Tsing Hua University, Hsinchu, Taiwan
| | - Yi-Hao Chang
- Department of Chemical Engineering, National Tsing Hua University, Hsinchu, Taiwan
| | - Yi Tu
- Department of Life Science, National Taiwan University, Taipei, Taiwan
| | - June-Yen Chou
- Innovation and R&D Division, Chang Chun Group, Taipei, Taiwan; Dairen Chemical Corp, Taipei, Taiwan
| | | | - Yu-Chen Hu
- Department of Chemical Engineering, National Tsing Hua University, Hsinchu, Taiwan; Frontier Research Center on Fundamental and Applied Sciences of Matters, National Tsing Hua University, Hsinchu, Taiwan.
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Geng B, Jia X, Peng X, Han Y. Biosynthesis of value-added bioproducts from hemicellulose of biomass through microbial metabolic engineering. Metab Eng Commun 2022; 15:e00211. [PMID: 36311477 PMCID: PMC9597109 DOI: 10.1016/j.mec.2022.e00211] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/04/2022] [Revised: 10/02/2022] [Accepted: 10/17/2022] [Indexed: 11/06/2022] Open
Abstract
Hemicellulose is the second most abundant carbohydrate in lignocellulosic biomass and has extensive applications. In conventional biomass refinery, hemicellulose is easily converted to unwanted by-products in pretreatment and therefore can't be fully utilized. The present study aims to summarize the most recent development of lignocellulosic polysaccharide degradation and fully convert it to value-added bioproducts through microbial and enzymatic catalysis. Firstly, bioprocess and microbial metabolic engineering for enhanced utilization of lignocellulosic carbohydrates were discussed. The bioprocess for degradation and conversion of natural lignocellulose to monosaccharides and organic acids using anaerobic thermophilic bacteria and thermostable glycoside hydrolases were summarized. Xylose transmembrane transporting systems in natural microorganisms and the latest strategies for promoting the transporting capacity by metabolic engineering were summarized. The carbon catabolite repression effect restricting xylose utilization in microorganisms, and metabolic engineering strategies developed for co-utilization of glucose and xylose were discussed. Secondly, the metabolic pathways of xylose catabolism in microorganisms were comparatively analyzed. Microbial metabolic engineering for converting xylose to value-added bioproducts based on redox pathways, non-redox pathways, pentose phosphate pathway, and improving inhibitors resistance were summarized. Thirdly, strategies for degrading lignocellulosic polysaccharides and fully converting hemicellulose to value-added bioproducts through microbial metabolic engineering were proposed. Hemicellulose is the main carbohydrate of biomass and has valuable applications. Hemicellulose is underutilized in conventional biomass refinery and pretreatment. Microbial and enzymatic catalysis were applied for hemicellulose utilization. Xylose is converted to value-added bioproducts by metabolic engineering.
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Affiliation(s)
- Biao Geng
- National Key Laboratory of Biochemical Engineering, Institute of Process Engineering, Chinese Academy of Sciences, Beijing, 100190, China,School of Chemical Engineering, University of Chinese Academy of Sciences, Beijing, 100049, China
| | - Xiaojing Jia
- National Key Laboratory of Biochemical Engineering, Institute of Process Engineering, Chinese Academy of Sciences, Beijing, 100190, China,School of Chemical Engineering, University of Chinese Academy of Sciences, Beijing, 100049, China
| | - Xiaowei Peng
- National Key Laboratory of Biochemical Engineering, Institute of Process Engineering, Chinese Academy of Sciences, Beijing, 100190, China,School of Chemical Engineering, University of Chinese Academy of Sciences, Beijing, 100049, China
| | - Yejun Han
- National Key Laboratory of Biochemical Engineering, Institute of Process Engineering, Chinese Academy of Sciences, Beijing, 100190, China,School of Chemical Engineering, University of Chinese Academy of Sciences, Beijing, 100049, China,Corresponding author. National Key Laboratory of Biochemical Engineering, Institute of Process Engineering, Chinese Academy of Sciences, Beijing, 100190, China.
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9
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Bever D, Wheeldon I, Da Silva N. RNA polymerase II-driven CRISPR-Cas9 system for efficient non-growth-biased metabolic engineering of Kluyveromyces marxianus. Metab Eng Commun 2022; 15:e00208. [PMID: 36249306 PMCID: PMC9558044 DOI: 10.1016/j.mec.2022.e00208] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/16/2022] [Revised: 09/07/2022] [Accepted: 09/23/2022] [Indexed: 11/24/2022] Open
Abstract
The thermotolerant yeast Kluyveromyces marxianus has gained significant attention in recent years as a promising microbial candidate for industrial biomanufacturing. Despite several contributions to the expanding molecular toolbox for gene expression and metabolic engineering of K. marxianus, there remains a need for a more efficient and versatile genome editing platform. To address this, we developed a CRISPR-based editing system that enables high efficiency marker-less gene disruptions and integrations using only 40 bp homology arms in NHEJ functional and non-functional K. marxianus strains. The use of a strong RNA polymerase II promoter allows efficient expression of gRNAs flanked by the self-cleaving RNA structures, tRNA and HDV ribozyme, from a single plasmid co-expressing a codon optimized Cas9. Implementing this system resulted in nearly 100% efficiency of gene disruptions in both NHEJ-functional and NHEJ-deficient K. marxianus strains, with donor integration efficiencies reaching 50% and 100% in the two strains, respectively. The high gRNA targeting performance also proved instrumental for selection of engineered strains with lower growth rate but improved polyketide biosynthesis by avoiding an extended outgrowth period, a common method used to enrich for edited cells but that fails to recover advantageous mutants with even slightly impaired fitness. Finally, we provide the first demonstration of simultaneous, markerless integrations at multiple loci in K. marxianus using a 2.6 kb and a 7.6 kb donor, achieving a dual integration efficiency of 25.5% in a NHEJ-deficient strain. These results highlight both the ease of use and general robustness of this system for rapid and flexible metabolic engineering in this non-conventional yeast. RNAP II-driven tRNA-gRNA-HDV ribozyme cassette built for K. marxianus genome editing. Gene integrations up to 7.6 kb were achieved with only 40 bp homology sequences. Recovery of growth-biased modifications achievable as extended outgrowth not required. Application (ZWF1 and GPD1 knockouts) increased polyketide specific titers. Expressing two unique gRNAs from one cassette enabled integrations at separate loci.
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10
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Fermentation performance of a Mexican native Clavispora lusitaniae strain for xylitol and ethanol production from xylose, glucose and cellobiose. Enzyme Microb Technol 2022; 160:110094. [PMID: 35810624 DOI: 10.1016/j.enzmictec.2022.110094] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/08/2022] [Revised: 07/01/2022] [Accepted: 07/03/2022] [Indexed: 11/21/2022]
Abstract
Lignocellulose hydrolysates are rich in fermentable sugars such as xylose, cellobiose and glucose, with high potential in the biotechnology industry to obtain bioproducts of higher economic value. Thus, it is important to search for and study new yeast strains that co-consume these sugars to achieve better yields and productivity in the processes. The yeast Clavispora lusitaniae CDBB-L-2031, a native strain isolated from mezcal must, was studied under various culture conditions to potentially produce ethanol and xylitol due to its ability to assimilate xylose, cellobiose and glucose. This yeast produced ethanol under microaerobic conditions with yields of 0.451 gethanol/gglucose and 0.344 gethanol/gcellobiose, when grown on 1% glucose or cellobiose, respectively. In mixtures (0.5% each) of glucose:xylose and glucose:xylose:cellobiose the yields were 0.367 gethanol/gGX and 0. 380 gethanol/gGXC, respectively. Likewise, in identical conditions, C. lusitaniae produced xylitol from xylose with a yield of 0.421 gxylitol/gxylose. In 5% glucose or xylose, this yeast had better ethanol and xylitol titers and yields, respectively. However, glucose negatively affected xylitol production in the mixture of both sugars (3% each), producing only ethanol. Xylose reductase (XR) and xylitol dehydrogenase (XDH) activities were evaluated in cultures growing on xylose or glucose, obtaining the highest values in cultures on xylose at 8 h (25.9 and 6.22 mU/mg, respectively). While in glucose cultures, XR and XDH activities were detected once this substrate was consumed (4.06 and 3.32 mU/mg, respectively). Finally, the XYL1 and XYL2 genes encoding xylose reductase and xylitol dehydrogenase, respectively, were up-regulated by xylose, whereas glucose down-regulated their expression.
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11
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Liang B, Sun G, Zhang X, Nie Q, Zhao Y, Yang J. Recent Advances, Challenges and Metabolic Engineering Strategies in the Biosynthesis of 3-Hydroxypropionic Acid. Biotechnol Bioeng 2022; 119:2639-2668. [PMID: 35781640 DOI: 10.1002/bit.28170] [Citation(s) in RCA: 13] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2021] [Revised: 04/26/2022] [Accepted: 06/29/2022] [Indexed: 11/07/2022]
Abstract
As an attractive and valuable platform chemical, 3-hydroxypropionic acid (3-HP) can be used to produce a variety of industrially important commodity chemicals and biodegradable polymers. Moreover, the biosynthesis of 3-HP has drawn much attention in recent years due to its sustainability and environmental friendliness. Here, we focus on recent advances, challenges and metabolic engineering strategies in the biosynthesis of 3-HP. While glucose and glycerol are major carbon sources for its production of 3-HP via microbial fermentation, other carbon sources have also been explored. To increase yield and titer, synthetic biology and metabolic engineering strategies have been explored, including modifying pathway enzymes, eliminating flux blockages due to byproduct synthesis, eliminating toxic byproducts, and optimizing via genome-scale models. This review also provides insights on future directions for 3-HP biosynthesis. This article is protected by copyright. All rights reserved.
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Affiliation(s)
- Bo Liang
- Energy-rich Compounds Production by Photosynthetic Carbon Fixation Research Center, Qingdao Agricultural University, Qingdao, China.,Shandong Key Lab of Applied Mycology, College of Life Sciences, Qingdao Agricultural University, Qingdao, China
| | - Guannan Sun
- Energy-rich Compounds Production by Photosynthetic Carbon Fixation Research Center, Qingdao Agricultural University, Qingdao, China.,Shandong Key Lab of Applied Mycology, College of Life Sciences, Qingdao Agricultural University, Qingdao, China
| | - Xinping Zhang
- Energy-rich Compounds Production by Photosynthetic Carbon Fixation Research Center, Qingdao Agricultural University, Qingdao, China.,Shandong Key Lab of Applied Mycology, College of Life Sciences, Qingdao Agricultural University, Qingdao, China
| | - Qingjuan Nie
- Foreign Languages School, Qingdao Agricultural University, Qingdao, China
| | - Yukun Zhao
- Pony Testing International Group, Qingdao, China
| | - Jianming Yang
- Energy-rich Compounds Production by Photosynthetic Carbon Fixation Research Center, Qingdao Agricultural University, Qingdao, China.,Shandong Key Lab of Applied Mycology, College of Life Sciences, Qingdao Agricultural University, Qingdao, China
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12
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Theodosiou E, Tüllinghoff A, Toepel J, Bühler B. Exploitation of Hetero- and Phototrophic Metabolic Modules for Redox-Intensive Whole-Cell Biocatalysis. Front Bioeng Biotechnol 2022; 10:855715. [PMID: 35497353 PMCID: PMC9043136 DOI: 10.3389/fbioe.2022.855715] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/15/2022] [Accepted: 03/09/2022] [Indexed: 11/13/2022] Open
Abstract
The successful realization of a sustainable manufacturing bioprocess and the maximization of its production potential and capacity are the main concerns of a bioprocess engineer. A main step towards this endeavor is the development of an efficient biocatalyst. Isolated enzyme(s), microbial cells, or (immobilized) formulations thereof can serve as biocatalysts. Living cells feature, beside active enzymes, metabolic modules that can be exploited to support energy-dependent and multi-step enzyme-catalyzed reactions. Metabolism can sustainably supply necessary cofactors or cosubstrates at the expense of readily available and cheap resources, rendering external addition of costly cosubstrates unnecessary. However, for the development of an efficient whole-cell biocatalyst, in depth comprehension of metabolic modules and their interconnection with cell growth, maintenance, and product formation is indispensable. In order to maximize the flux through biosynthetic reactions and pathways to an industrially relevant product and respective key performance indices (i.e., titer, yield, and productivity), existing metabolic modules can be redesigned and/or novel artificial ones established. This review focuses on whole-cell bioconversions that are coupled to heterotrophic or phototrophic metabolism and discusses metabolic engineering efforts aiming at 1) increasing regeneration and supply of redox equivalents, such as NAD(P/H), 2) blocking competing fluxes, and 3) increasing the availability of metabolites serving as (co)substrates of desired biosynthetic routes.
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Affiliation(s)
- Eleni Theodosiou
- Institute of Applied Biosciences, Centre for Research and Technology Hellas, Thessaloniki, Greece
| | - Adrian Tüllinghoff
- Department of Solar Materials, Helmholtz Centre for Environmental Research GmbH—UFZ, Leipzig, Germany
| | - Jörg Toepel
- Department of Solar Materials, Helmholtz Centre for Environmental Research GmbH—UFZ, Leipzig, Germany
| | - Bruno Bühler
- Department of Solar Materials, Helmholtz Centre for Environmental Research GmbH—UFZ, Leipzig, Germany
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13
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Optimization of Asymmetric Bioreduction Conditions of 2-methyl-1-phenylpropan-1-one by Lactobacillus fermentum BY35 Using I-Optimal Design-Based Model. ARABIAN JOURNAL FOR SCIENCE AND ENGINEERING 2022. [DOI: 10.1007/s13369-021-06434-5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
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14
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Baptista M, Cunha JT, Domingues L. Establishment of Kluyveromyces marxianus as a Microbial Cell Factory for Lignocellulosic Processes: Production of High Value Furan Derivatives. J Fungi (Basel) 2021; 7:1047. [PMID: 34947029 PMCID: PMC8708846 DOI: 10.3390/jof7121047] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/05/2021] [Revised: 11/30/2021] [Accepted: 12/02/2021] [Indexed: 12/19/2022] Open
Abstract
The establishment of lignocellulosic biorefineries is dependent on microorganisms being able to cope with the stressful conditions resulting from the release of inhibitory compounds during biomass processing. The yeast Kluyveromyces marxianus has been explored as an alternative microbial factory due to its thermotolerance and ability to natively metabolize xylose. The lignocellulose-derived inhibitors furfural and 5-hydroxymethylfurfural (HMF) are considered promising building-block platforms that can be converted into a wide variety of high-value derivatives. Here, several K. marxianus strains, isolated from cocoa fermentation, were evaluated for xylose consumption and tolerance towards acetic acid, furfural, and HMF. The potential of this yeast to reduce furfural and HMF at high inhibitory loads was disclosed and characterized. Our results associated HMF reduction with NADPH while furfural-reducing activity was higher with NADH. In addition, furans' inhibitory effect was higher when combined with xylose consumption. The furan derivatives produced by K. marxianus in different conditions were identified. Furthermore, one selected isolate was efficiently used as a whole-cell biocatalyst to convert furfural and HMF into their derivatives, furfuryl alcohol and 2,5-bis(hydroxymethyl)furan (BHMF), with high yields and productivities. These results validate K. marxianus as a promising microbial platform in lignocellulosic biorefineries.
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Affiliation(s)
| | | | - Lucília Domingues
- CEB—Centre of Biological Engineering, University of Minho, Campus de Gualtar, 4710-057 Braga, Portugal; (M.B.); (J.T.C.)
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15
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D-Galacturonic acid reduction by S. cerevisiae for L-galactonate production from extracted sugar beet press pulp hydrolysate. Appl Microbiol Biotechnol 2021; 105:5795-5807. [PMID: 34268581 PMCID: PMC8390429 DOI: 10.1007/s00253-021-11433-5] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/22/2021] [Revised: 06/03/2021] [Accepted: 06/25/2021] [Indexed: 11/06/2022]
Abstract
Abstract Pectin-rich residues are considered as promising feedstocks for sustainable production of platform chemicals. Enzymatic hydrolysis of extracted sugar beet press pulp (SBPP) releases the main constituent of pectin, d-galacturonic acid (d-GalA). Using engineered Saccharomyces cerevisiae, d-GalA is then reduced to l-galactonate (l-GalOA) with sorbitol as co-substrate. The current work addresses the combination of enzymatic hydrolysis of pectin in SBPP with a consecutive optimized biotransformation of the released d-GalA to l-GalOA in simple batch processes in stirred-tank bioreactors. Process conditions were first identified with synthetic media, where a product concentration of 9.9 g L-1 L-GalOA was obtained with a product selectivity of 99% (L-GalOA D-GalA-1) at pH 5 with 4% (w/v) sorbitol within 48 h. A very similar batch process performance with a product selectivity of 97% was achieved with potassium citrate buffered SBPP hydrolysate, demonstrating for the first time direct production of L-GalOA from hydrolyzed biomass using engineered S. cerevisiae. Combining the hydrolysis process of extracted SBPP and the biotransformation process with engineered S. cerevisiae paves the way towards repurposing pectin-rich residues as substrates for value-added chemicals. Key points • Efficient bioreduction of D-GalA with S. cerevisiae in stirred-tank reactors • Batch production of L-GalOA by engineered S. cerevisiae with high selectivity • Direct L-GalOA production from hydrolyzed sugar beet press pulp Graphical abstract Bioreduction of D-galacturonic acid to L-galactonate with recombinant Saccharomyces cerevisiae enables for the first time the valorization of hydrolysates from extracted sugar beet press pulp for the sustainable production of value-added chemicals. ![]()
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16
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Zhang L, Chen Z, Wang J, Shen W, Li Q, Chen X. Stepwise metabolic engineering of Candida tropicalis for efficient xylitol production from xylose mother liquor. Microb Cell Fact 2021; 20:105. [PMID: 34034730 PMCID: PMC8147403 DOI: 10.1186/s12934-021-01596-1] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/22/2021] [Accepted: 05/15/2021] [Indexed: 11/11/2022] Open
Abstract
Background Commercial xylose purification produces xylose mother liquor (XML) as a major byproduct, which has become an inexpensive and abundant carbon source. A portion of this XML has been used to produce low-value-added products such as caramel but the remainder often ends up as an organic pollutant. This has become an issue of industrial concern. In this study, a uracil-deficient Candida tropicalis strain was engineered to efficiently convert XML to the commercially useful product xylitol. Results The xylitol dehydrogenase gene was deleted to block the conversion of xylitol to xylulose. Then, an NADPH regeneration system was added through heterologous expression of the Yarrowia lipolytica genes encoding 6-phosphate-gluconic acid dehydrogenase and 6-phosphate-glucose dehydrogenase. After process optimization, the engineered strain, C. tropicalis XZX-B4ZG, produced 97.10 g L− 1 xylitol in 120 h from 300 g L− 1 XML in a 5-L fermenter. The xylitol production rate was 0.82 g L− 1 h− 1 and the conversion rate was 92.40 %. Conclusions In conclusion, this study performed a combination of metabolic engineering and process optimizing in C. tropicalis to enhance xylitol production from XML. The use of C. tropicalis XZX-B4ZG, therefore, provided a convenient method to transform the industrial by-product XML into the useful material xylitol. Supplementary Information The online version contains supplementary material available at 10.1186/s12934-021-01596-1.
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Affiliation(s)
- Lihua Zhang
- Key Laboratory of Industrial Biotechnology, Ministry of Education, School of Biotechnology, Jiangnan University, 1800 Lihu Road, Wuxi, 214122, People's Republic of China
| | - Zhen Chen
- Key Laboratory of Industrial Biotechnology, Ministry of Education, School of Biotechnology, Jiangnan University, 1800 Lihu Road, Wuxi, 214122, People's Republic of China
| | - Junhua Wang
- Key Laboratory of Industrial Biotechnology, Ministry of Education, School of Biotechnology, Jiangnan University, 1800 Lihu Road, Wuxi, 214122, People's Republic of China
| | - Wei Shen
- Key Laboratory of Industrial Biotechnology, Ministry of Education, School of Biotechnology, Jiangnan University, 1800 Lihu Road, Wuxi, 214122, People's Republic of China
| | - Qi Li
- Key Laboratory of Industrial Biotechnology, Ministry of Education, School of Biotechnology, Jiangnan University, 1800 Lihu Road, Wuxi, 214122, People's Republic of China.
| | - Xianzhong Chen
- Key Laboratory of Industrial Biotechnology, Ministry of Education, School of Biotechnology, Jiangnan University, 1800 Lihu Road, Wuxi, 214122, People's Republic of China.
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17
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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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18
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Sui YF, Schütze T, Ouyang LM, Lu H, Liu P, Xiao X, Qi J, Zhuang YP, Meyer V. Engineering cofactor metabolism for improved protein and glucoamylase production in Aspergillus niger. Microb Cell Fact 2020; 19:198. [PMID: 33097040 PMCID: PMC7584080 DOI: 10.1186/s12934-020-01450-w] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/08/2020] [Accepted: 10/07/2020] [Indexed: 01/26/2023] Open
Abstract
Background Nicotinamide adenine dinucleotide phosphate (NADPH) is an important cofactor ensuring intracellular redox balance, anabolism and cell growth in all living systems. Our recent multi-omics analyses of glucoamylase (GlaA) biosynthesis in the filamentous fungal cell factory Aspergillus niger indicated that low availability of NADPH might be a limiting factor for GlaA overproduction. Results We thus employed the Design-Build-Test-Learn cycle for metabolic engineering to identify and prioritize effective cofactor engineering strategies for GlaA overproduction. Based on available metabolomics and 13C metabolic flux analysis data, we individually overexpressed seven predicted genes encoding NADPH generation enzymes under the control of the Tet-on gene switch in two A. niger recipient strains, one carrying a single and one carrying seven glaA gene copies, respectively, to test their individual effects on GlaA and total protein overproduction. Both strains were selected to understand if a strong pull towards glaA biosynthesis (seven gene copies) mandates a higher NADPH supply compared to the native condition (one gene copy). Detailed analysis of all 14 strains cultivated in shake flask cultures uncovered that overexpression of the gsdA gene (glucose 6-phosphate dehydrogenase), gndA gene (6-phosphogluconate dehydrogenase) and maeA gene (NADP-dependent malic enzyme) supported GlaA production on a subtle (10%) but significant level in the background strain carrying seven glaA gene copies. We thus performed maltose-limited chemostat cultures combining metabolome analysis for these three isolates to characterize metabolic-level fluctuations caused by cofactor engineering. In these cultures, overexpression of either the gndA or maeA gene increased the intracellular NADPH pool by 45% and 66%, and the yield of GlaA by 65% and 30%, respectively. In contrast, overexpression of the gsdA gene had a negative effect on both total protein and glucoamylase production. Conclusions This data suggests for the first time that increased NADPH availability can indeed underpin protein and especially GlaA production in strains where a strong pull towards GlaA biosynthesis exists. This data also indicates that the highest impact on GlaA production can be engineered on a genetic level by increasing the flux through the pentose phosphate pathway (gndA gene) followed by engineering the flux through the reverse TCA cycle (maeA gene). We thus propose that NADPH cofactor engineering is indeed a valid strategy for metabolic engineering of A. niger to improve GlaA production, a strategy which is certainly also applicable to the rational design of other microbial cell factories.![]()
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Affiliation(s)
- Yu-Fei Sui
- State Key Laboratory of Bioreactor Engineering, East China University of Science and Technology, Shanghai, 200237, People's Republic of China.,Chair of Applied and Molecular Microbiology, Institute of Biotechnology, Technische Universität Berlin, Straße des 17. Juni 135, 10623, Berlin, Germany
| | - Tabea Schütze
- Chair of Applied and Molecular Microbiology, Institute of Biotechnology, Technische Universität Berlin, Straße des 17. Juni 135, 10623, Berlin, Germany
| | - Li-Ming Ouyang
- State Key Laboratory of Bioreactor Engineering, East China University of Science and Technology, Shanghai, 200237, People's Republic of China
| | - Hongzhong Lu
- Department of Biology and Biological Engineering, Chalmers University of Technology, Kemivägen 10, 412 96, Gothenburg, Sweden
| | - Peng Liu
- State Key Laboratory of Bioreactor Engineering, East China University of Science and Technology, Shanghai, 200237, People's Republic of China
| | - Xianzun Xiao
- State Key Laboratory of Bioreactor Engineering, East China University of Science and Technology, Shanghai, 200237, People's Republic of China
| | - Jie Qi
- State Key Laboratory of Bioreactor Engineering, East China University of Science and Technology, Shanghai, 200237, People's Republic of China
| | - Ying-Ping Zhuang
- State Key Laboratory of Bioreactor Engineering, East China University of Science and Technology, Shanghai, 200237, People's Republic of China.
| | - Vera Meyer
- Chair of Applied and Molecular Microbiology, Institute of Biotechnology, Technische Universität Berlin, Straße des 17. Juni 135, 10623, Berlin, Germany.
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19
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Nijland JG, Driessen AJM. Engineering of Pentose Transport in Saccharomyces cerevisiae for Biotechnological Applications. Front Bioeng Biotechnol 2020; 7:464. [PMID: 32064252 PMCID: PMC7000353 DOI: 10.3389/fbioe.2019.00464] [Citation(s) in RCA: 33] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/14/2019] [Accepted: 12/19/2019] [Indexed: 01/05/2023] Open
Abstract
Lignocellulosic biomass yields after hydrolysis, besides the hexose D-glucose, D-xylose, and L-arabinose as main pentose sugars. In second generation bioethanol production utilizing the yeast Saccharomyces cerevisiae, it is critical that all three sugars are co-consumed to obtain an economically feasible and robust process. Since S. cerevisiae is unable to metabolize pentose sugars, metabolic pathway engineering has been employed to introduce the respective pathways for D-xylose and L-arabinose metabolism. However, S. cerevisiae lacks specific pentose transporters, and these sugars enter the cell with low affinity via glucose transporters of the Hxt family. Therefore, in the presence of D-glucose, utilization of D-xylose and L-arabinose is poor as the Hxt transporters prefer D-glucose. To solve this problem, heterologous expression of pentose transporters has been attempted but often with limited success due to poor expression and stability, and/or low turnover. A more successful approach is the engineering of the endogenous Hxt transporter family and evolutionary selection for D-glucose insensitive growth on pentose sugars. This has led to the identification of a critical and conserved asparagine residue in Hxt transporters that, when mutated, reduces the D-glucose affinity while leaving the D-xylose affinity mostly unaltered. Likewise, mutant Gal2 transporter have been selected supporting specific uptake of L-arabinose. In fermentation experiments, the transporter mutants support efficient uptake and consumption of pentose sugars, and even co-consumption of D-xylose and D-glucose when used at industrial concentrations. Further improvements are obtained by interfering with the post-translational inactivation of Hxt transporters at high or low D-glucose concentrations. Transporter engineering solved major limitations in pentose transport in yeast, now allowing for co-consumption of sugars that is limited only by the rates of primary metabolism. This paves the way for a more economical second-generation biofuels production process.
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Affiliation(s)
- Jeroen G Nijland
- Molecular Microbiology, Groningen Biomolecular Sciences and Biotechnology, University of Groningen, Groningen, Netherlands
| | - Arnold J M Driessen
- Molecular Microbiology, Groningen Biomolecular Sciences and Biotechnology, University of Groningen, Groningen, Netherlands
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20
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Şahin E. First green synthesis of (R)-2-methyl-1-phenylpropan-1-ol using whole-cell Lactobacillus paracasei BD101 biotransformation. BIOCATAL BIOTRANSFOR 2019. [DOI: 10.1080/10242422.2019.1698554] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
Affiliation(s)
- Engin Şahin
- Faculty of Engineering, Department of Food Engineering, Bayburt University, Bayburt, Turkey
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21
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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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22
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Saa PA, Cortés MP, López J, Bustos D, Maass A, Agosin E. Expanding Metabolic Capabilities Using Novel Pathway Designs: Computational Tools and Case Studies. Biotechnol J 2019; 14:e1800734. [DOI: 10.1002/biot.201800734] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2018] [Revised: 04/22/2019] [Indexed: 11/10/2022]
Affiliation(s)
- Pedro A. Saa
- Departamento de Ingeniería Química y BioprocesosPontificia Universidad Católica de Chile Av. Vicuña Mackenna 4860 7820436 Santiago Chile
| | - María P. Cortés
- Centro de Modelamiento MatemáticoUniversidad de Chile Av. Beaucheff 851 Santiago 8370456 Chile
- Centro de Regulación del GenomaUniversidad de Chile Av. Beaucheff 851 Santiago 8370456 Chile
| | - Javiera López
- Centro de Aromas y SaboresDICTUC S.A Av. Vicuña Mackenna 4860 Santiago 7820436 Chile
| | - Diego Bustos
- Centro de Aromas y SaboresDICTUC S.A Av. Vicuña Mackenna 4860 Santiago 7820436 Chile
| | - Alejandro Maass
- Centro de Modelamiento MatemáticoUniversidad de Chile Av. Beaucheff 851 Santiago 8370456 Chile
- Departmento de Ingeniería MatemáticaUniversidad de Chile Av. Beaucheff 851 Santiago 8370456 Chile
| | - Eduardo Agosin
- Departamento de Ingeniería Química y BioprocesosPontificia Universidad Católica de Chile Av. Vicuña Mackenna 4860 7820436 Santiago Chile
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23
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Xu W, Yao J, Liu L, Ma X, Li W, Sun X, Wang Y. Improving squalene production by enhancing the NADPH/NADP + ratio, modifying the isoprenoid-feeding module and blocking the menaquinone pathway in Escherichia coli. BIOTECHNOLOGY FOR BIOFUELS 2019; 12:68. [PMID: 30962822 PMCID: PMC6437923 DOI: 10.1186/s13068-019-1415-x] [Citation(s) in RCA: 26] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/30/2019] [Accepted: 03/20/2019] [Indexed: 05/27/2023]
Abstract
BACKGROUND Squalene is currently used widely in the food, cosmetics, and medicine industries. It could also replace petroleum as a raw material for fuels. Microbial fermentation processes for squalene production have been emerging over recent years. In this study, to study the squalene-producing potential of Escherichia coli (E. coli), we employed several increasing strategies for systematic metabolic engineering. These include the expression of human truncated squalene synthase, the overexpression of rate-limiting enzymes in isoprenoid pathway, the modification of isoprenoid-feeding module and the blocking of menaquinone pathway. RESULTS Herein, human truncated squalene synthase was engineered in Escherichia coli to create a squalene-producing bacterial strain. To increase squalene yield, we employed several metabolic engineering strategies. A fivefold squalene titer increase was achieved by expressing rate-limiting enzymes (IDI, DXS, and FPS) involved in the isoprenoid pathway. Pyridine nucleotide transhydrogenase (UdhA) was then expressed to improve the cellular NADPH/NADP+ ratio, resulting in a 59% increase in squalene titer. The Embden-Meyerhof pathway (EMP) was replaced with the Entner-Doudoroff pathway (EDP) and pentose phosphate pathway (PPP) to feed the isoprenoid pathway, along with the overexpression of zwf and pgl genes which encode rate-limiting enzymes in the EDP and PPP, leading to a 104% squalene content increase. Based on the blocking of menaquinone pathway, a further 17.7% increase in squalene content was achieved. Squalene content reached a final 28.5 mg/g DCW and 52.1 mg/L. CONCLUSIONS This study provided novel strategies for improving squalene yield and demonstrated the potential of producing squalene by E. coli.
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Affiliation(s)
- Wen Xu
- The Molecular Virology and Viral Immunology Laboratory, Xi’an Medical University, Xi’an, 710021 Shaanxi China
| | - Jia Yao
- The Molecular Virology and Viral Immunology Laboratory, Xi’an Medical University, Xi’an, 710021 Shaanxi China
| | - Lijun Liu
- The Molecular Virology and Viral Immunology Laboratory, Xi’an Medical University, Xi’an, 710021 Shaanxi China
| | - Xi Ma
- The Molecular Virology and Viral Immunology Laboratory, Xi’an Medical University, Xi’an, 710021 Shaanxi China
| | - Wei Li
- The Molecular Virology and Viral Immunology Laboratory, Xi’an Medical University, Xi’an, 710021 Shaanxi China
| | - Xiaojing Sun
- The Molecular Virology and Viral Immunology Laboratory, Xi’an Medical University, Xi’an, 710021 Shaanxi China
| | - Yang Wang
- The Molecular Virology and Viral Immunology Laboratory, Xi’an Medical University, Xi’an, 710021 Shaanxi China
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Myers KS, Riley NM, MacGilvray ME, Sato TK, McGee M, Heilberger J, Coon JJ, Gasch AP. Rewired cellular signaling coordinates sugar and hypoxic responses for anaerobic xylose fermentation in yeast. PLoS Genet 2019; 15:e1008037. [PMID: 30856163 PMCID: PMC6428351 DOI: 10.1371/journal.pgen.1008037] [Citation(s) in RCA: 22] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/10/2018] [Revised: 03/21/2019] [Accepted: 02/20/2019] [Indexed: 01/08/2023] Open
Abstract
Microbes can be metabolically engineered to produce biofuels and biochemicals, but rerouting metabolic flux toward products is a major hurdle without a systems-level understanding of how cellular flux is controlled. To understand flux rerouting, we investigated a panel of Saccharomyces cerevisiae strains with progressive improvements in anaerobic fermentation of xylose, a sugar abundant in sustainable plant biomass used for biofuel production. We combined comparative transcriptomics, proteomics, and phosphoproteomics with network analysis to understand the physiology of improved anaerobic xylose fermentation. Our results show that upstream regulatory changes produce a suite of physiological effects that collectively impact the phenotype. Evolved strains show an unusual co-activation of Protein Kinase A (PKA) and Snf1, thus combining responses seen during feast on glucose and famine on non-preferred sugars. Surprisingly, these regulatory changes were required to mount the hypoxic response when cells were grown on xylose, revealing a previously unknown connection between sugar source and anaerobic response. Network analysis identified several downstream transcription factors that play a significant, but on their own minor, role in anaerobic xylose fermentation, consistent with the combinatorial effects of small-impact changes. We also discovered that different routes of PKA activation produce distinct phenotypes: deletion of the RAS/PKA inhibitor IRA2 promotes xylose growth and metabolism, whereas deletion of PKA inhibitor BCY1 decouples growth from metabolism to enable robust fermentation without division. Comparing phosphoproteomic changes across ira2Δ and bcy1Δ strains implicated regulatory changes linked to xylose-dependent growth versus metabolism. Together, our results present a picture of the metabolic logic behind anaerobic xylose flux and suggest that widespread cellular remodeling, rather than individual metabolic changes, is an important goal for metabolic engineering.
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Affiliation(s)
- Kevin S. Myers
- Great Lakes Bioenergy Research Center, University of Wisconsin-Madison, Madison, WI, United States of America
| | - Nicholas M. Riley
- Department of Chemistry, University of Wisconsin-Madison, Madison, WI, United States of America
| | - Matthew E. MacGilvray
- Laboratory of Genetics, University of Wisconsin-Madison, Madison, WI, United States of America
| | - Trey K. Sato
- Great Lakes Bioenergy Research Center, University of Wisconsin-Madison, Madison, WI, United States of America
| | - Mick McGee
- Great Lakes Bioenergy Research Center, University of Wisconsin-Madison, Madison, WI, United States of America
| | - Justin Heilberger
- Great Lakes Bioenergy Research Center, University of Wisconsin-Madison, Madison, WI, United States of America
| | - Joshua J. Coon
- Department of Chemistry, University of Wisconsin-Madison, Madison, WI, United States of America
- Genome Center of Wisconsin, University of Wisconsin-Madison, Madison, WI, United States of America
- Department of Biomolecular Chemistry, University of Wisconsin-Madison, Madison, WI, United States of America
- Morgridge Institute for Research, Madison, WI, United States of America
| | - Audrey P. Gasch
- Great Lakes Bioenergy Research Center, University of Wisconsin-Madison, Madison, WI, United States of America
- Laboratory of Genetics, University of Wisconsin-Madison, Madison, WI, United States of America
- Genome Center of Wisconsin, University of Wisconsin-Madison, Madison, WI, United States of America
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25
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Meshram SH, Ramesh T, Nanubolu JB, Srivastava AK, Adari BR, Sahu N. Green synthesis of enantiopure quinoxaline alcohols using Daucus carota. Chirality 2019; 31:312-320. [PMID: 30702777 DOI: 10.1002/chir.23057] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/02/2018] [Revised: 12/20/2018] [Accepted: 12/21/2018] [Indexed: 11/11/2022]
Abstract
Green chemistry comprises a new approach in the synthesis of biologically active compounds using biocatalysts, thus diminishing the hazards for human health and environmental pollution. Asymmetric bioreduction is one of the most widely employed strategies in chemoenzymatic synthesis to produce enantiomerically pure chiral alcohols. The present study highlights the use biocatalyst Daucus carota for selective bioreduction of quinoxaline ketones 1a-6a to their corresponding optically pure alcohols 1b-6b in high yields (up to 84%) and good enantioselectivity (up to 98%). The absolute configuration of the chiral product (R)-1-(3-methyl 7-nitroquinoxalin-2-yl) ethan-1-ol 2b was confirmed by X-ray crystallography studies. The chiral R-configuration of the products obtained was confirmed by absolute configuration studies and was assigned following anti-Prelogs rule. Quinoxaline pharmacophores form a part of well-known potent drug molecules; hence, the chiral products were studied for determination of their molecular properties using SwissADME property analyser. All the chiral products show no Lipinski rule violations and are expected to have good oral bioavailability. As per the molecular properties prediction studies, the compound 6b (R)-1-(6,7-dichloro-3- methylquinoxalin-2-yl) ethanol is observed to show the best physicochemical properties to be a good lead molecule. Thus, the sustainable methodology was developed, and it confirms the synthesis of novel quinoxaline chiral alcohols in a simple, inexpensive, and eco-friendly condition using D carota.
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Affiliation(s)
- Sneha H Meshram
- Academy of Scientific and Innovative Research (AcSIR), Council of Scientific and Industrial Research (CSIR), New Delhi, India.,Medicinal Chemistry and Biotechnology Division, CSIR-Indian Institute of Chemical Technology, Tarnaka, Hyderabad, India
| | - Tungana Ramesh
- Academy of Scientific and Innovative Research (AcSIR), Council of Scientific and Industrial Research (CSIR), New Delhi, India.,Medicinal Chemistry and Biotechnology Division, CSIR-Indian Institute of Chemical Technology, Tarnaka, Hyderabad, India
| | - Jagadeesh Babu Nanubolu
- Laboratory of X-ray Crystallography, CSIR-Indian Institute of Chemical Technology, Tarnaka, Hyderabad, India
| | - Ajay Kumar Srivastava
- Medicinal and Process Chemistry, CSIR-Central Drug Research Institute, Lucknow, India
| | - Bhaskar Rao Adari
- Medicinal Chemistry and Biotechnology Division, CSIR-Indian Institute of Chemical Technology, Tarnaka, Hyderabad, India
| | - Nivedita Sahu
- Chemical Engineering Division, CSIR-Indian Institute of Chemical Technology, Tarnaka, Hyderabad, India
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26
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Gao M, Ploessl D, Shao Z. Enhancing the Co-utilization of Biomass-Derived Mixed Sugars by Yeasts. Front Microbiol 2019; 9:3264. [PMID: 30723464 PMCID: PMC6349770 DOI: 10.3389/fmicb.2018.03264] [Citation(s) in RCA: 28] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/25/2018] [Accepted: 12/14/2018] [Indexed: 12/11/2022] Open
Abstract
Plant biomass is a promising carbon source for producing value-added chemicals, including transportation biofuels, polymer precursors, and various additives. Most engineered microbial hosts and a select group of wild-type species can metabolize mixed sugars including oligosaccharides, hexoses, and pentoses that are hydrolyzed from plant biomass. However, most of these microorganisms consume glucose preferentially to non-glucose sugars through mechanisms generally defined as carbon catabolite repression. The current lack of simultaneous mixed-sugar utilization limits achievable titers, yields, and productivities. Therefore, the development of microbial platforms capable of fermenting mixed sugars simultaneously from biomass hydrolysates is essential for economical industry-scale production, particularly for compounds with marginal profits. This review aims to summarize recent discoveries and breakthroughs in the engineering of yeast cell factories for improved mixed-sugar co-utilization based on various metabolic engineering approaches. Emphasis is placed on enhanced non-glucose utilization, discovery of novel sugar transporters free from glucose repression, native xylose-utilizing microbes, consolidated bioprocessing (CBP), improved cellulase secretion, and creation of microbial consortia for improving mixed-sugar utilization. Perspectives on the future development of biorenewables industry are provided in the end.
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Affiliation(s)
- Meirong Gao
- Department of Chemical and Biological Engineering, Iowa State University, Ames, IA, United States.,NSF Engineering Research Center for Biorenewable Chemicals (CBiRC), Iowa State University, Ames, IA, United States
| | - Deon Ploessl
- Department of Chemical and Biological Engineering, Iowa State University, Ames, IA, United States.,NSF Engineering Research Center for Biorenewable Chemicals (CBiRC), Iowa State University, Ames, IA, United States
| | - Zengyi Shao
- Department of Chemical and Biological Engineering, Iowa State University, Ames, IA, United States.,NSF Engineering Research Center for Biorenewable Chemicals (CBiRC), Iowa State University, Ames, IA, United States.,The Ames Laboratory, Iowa State University, Ames, IA, United States.,The Interdisciplinary Microbiology Program, Biorenewables Research Laboratory, Iowa State University, Ames, IA, United States
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27
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Hemansi, Gupta R, Yadav G, Kumar G, Yadav A, Saini JK, Kuhad RC. Second Generation Bioethanol Production: The State of Art. BIOFUEL AND BIOREFINERY TECHNOLOGIES 2019. [DOI: 10.1007/978-3-319-94797-6_8] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/06/2023]
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28
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Cunha JT, Soares PO, Romaní A, Thevelein JM, Domingues L. Xylose fermentation efficiency of industrial Saccharomyces cerevisiae yeast with separate or combined xylose reductase/xylitol dehydrogenase and xylose isomerase pathways. BIOTECHNOLOGY FOR BIOFUELS 2019; 12:20. [PMID: 30705706 PMCID: PMC6348659 DOI: 10.1186/s13068-019-1360-8] [Citation(s) in RCA: 68] [Impact Index Per Article: 13.6] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/20/2018] [Accepted: 01/18/2019] [Indexed: 05/12/2023]
Abstract
BACKGROUND Xylose isomerase (XI) and xylose reductase/xylitol dehydrogenase (XR/XDH) pathways have been extensively used to confer xylose assimilation capacity to Saccharomyces cerevisiae and tackle one of the major bottlenecks in the attainment of economically viable lignocellulosic ethanol production. Nevertheless, there is a lack of studies comparing the efficiency of those pathways both separately and combined. In this work, the XI and/or XR/XDH pathways were introduced into two robust industrial S. cerevisiae strains, evaluated in synthetic media and corn cob hemicellulosic hydrolysate and the results were correlated with the differential enzyme activities found in the xylose-pathway engineered strains. RESULTS The sole expression of XI was found to increase the fermentative capacity of both strains in synthetic media at 30 °C and 40 °C: decreasing xylitol accumulation and improving xylose consumption and ethanol production. Similar results were observed in fermentations of detoxified hydrolysate. However, in the presence of lignocellulosic-derived inhibitors, a positive synergistic effect resulted from the expression of both XI and XR/XDH, possibly caused by a cofactor equilibrium between the XDH and furan detoxifying enzymes, increasing the ethanol yield by more than 38%. CONCLUSIONS This study clearly shows an advantage of using the XI from Clostridium phytofermentans to attain high ethanol productivities and yields from xylose. Furthermore, and for the first time, the simultaneous utilization of XR/XDH and XI pathways was compared to the single expression of XR/XDH or XI and was found to improve ethanol production from non-detoxified hemicellulosic hydrolysates. These results extend the knowledge regarding S. cerevisiae xylose assimilation metabolism and pave the way for the construction of more efficient strains for use in lignocellulosic industrial processes.
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Affiliation(s)
- Joana T. Cunha
- CEB-Centre of Biological Engineering, University of Minho, 4710-057 Braga, Portugal
| | - Pedro O. Soares
- CEB-Centre of Biological Engineering, University of Minho, 4710-057 Braga, Portugal
| | - Aloia Romaní
- CEB-Centre of Biological Engineering, University of Minho, 4710-057 Braga, Portugal
| | - Johan M. Thevelein
- Laboratory of Molecular Cell Biology, Institute of Botany and Microbiology, Department of Biology, KU Leuven, Kasteelpark Arenberg 31, 3001 Leuven-Heverlee, Flanders Belgium
- Center for Microbiology, VIB, Kasteelpark Arenberg 31, 3001 Leuven-Heverlee, Flanders Belgium
| | - Lucília Domingues
- CEB-Centre of Biological Engineering, University of Minho, 4710-057 Braga, Portugal
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29
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Ji RY, Ding Y, Shi TQ, Lin L, Huang H, Gao Z, Ji XJ. Metabolic Engineering of Yeast for the Production of 3-Hydroxypropionic Acid. Front Microbiol 2018; 9:2185. [PMID: 30298059 PMCID: PMC6160737 DOI: 10.3389/fmicb.2018.02185] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2018] [Accepted: 08/27/2018] [Indexed: 02/05/2023] Open
Abstract
The beta-hydroxy acid 3-hydroxypropionic acid (3-HP) is an attractive platform compound that can be used as a precursor for many commercially interesting compounds. In order to reduce the dependence on petroleum and follow sustainable development, 3-HP has been produced biologically from glucose or glycerol. It is reported that 3-HP synthesis pathways can be constructed in microbes such as Escherichia coli, Klebsiella pneumoniae and the yeast Saccharomyces cerevisiae. Among these host strains, yeast is prominent because of its strong acid tolerance which can simplify the fermentation process. Currently, the malonyl-CoA reductase pathway and the β-alanine pathway have been successfully constructed in yeast. This review presents the current developments in 3-HP production using yeast as an industrial host. By combining genome-scale engineering tools, malonyl-CoA biosensors and optimization of downstream fermentation, the production of 3-HP in yeast has the potential to reach or even exceed the yield of chemical production in the future.
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Affiliation(s)
- Rong-Yu Ji
- College of Biotechnology and Pharmaceutical Engineering, Nanjing Tech University, Nanjing, China
| | - Ying Ding
- College of Biotechnology and Pharmaceutical Engineering, Nanjing Tech University, Nanjing, China
| | - Tian-Qiong Shi
- College of Biotechnology and Pharmaceutical Engineering, Nanjing Tech University, Nanjing, China
| | - Lu Lin
- School of Pharmaceutical Sciences, Nanjing Tech University, Nanjing, China
| | - He Huang
- School of Pharmaceutical Sciences, Nanjing Tech University, Nanjing, China
- State Key Laboratory of Materials-Oriented Chemical Engineering, Nanjing Tech University, Nanjing, China
- Jiangsu National Synergetic Innovation Center for Advanced Materials, Nanjing Tech University, Nanjing, China
| | - Zhen Gao
- College of Biotechnology and Pharmaceutical Engineering, Nanjing Tech University, Nanjing, China
| | - Xiao-Jun Ji
- College of Biotechnology and Pharmaceutical Engineering, Nanjing Tech University, Nanjing, China
- Jiangsu National Synergetic Innovation Center for Advanced Materials, Nanjing Tech University, Nanjing, China
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30
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Qi F, Thakker C, Zhu F, Pena M, San KY, Bennett GN. Improvement of butanol production in Clostridium acetobutylicum through enhancement of NAD(P)H availability. J Ind Microbiol Biotechnol 2018; 45:993-1002. [PMID: 30141107 DOI: 10.1007/s10295-018-2068-7] [Citation(s) in RCA: 20] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/29/2018] [Accepted: 08/13/2018] [Indexed: 01/14/2023]
Abstract
Clostridium acetobutylicum is a natural producer of butanol, butyrate, acetone and ethanol. The pattern of metabolites reflects the partitioning of redox equivalents between hydrogen and carbon metabolites. Here the exogenous genes of ferredoxin-NAD(P)+ oxidoreductase (FdNR) and trans-enoyl-coenzyme reductase (TER) are introduced to three different Clostridium acetobutylicum strains to investigate the distribution of redox equivalents and butanol productivity. The FdNR improves NAD(P)H availability by capturing reducing power from ferredoxin. A butanol production of 9.01 g/L (36.9% higher than the control), and the highest ratios of butanol/acetate (7.02) and C4/C2 (3.17) derived metabolites were obtained in the C acetobutylicum buk- strain expressing FdNR. While the TER functions as an NAD(P)H oxidase, butanol production was decreased in the C. acetobutylicum strains containing TER. The results illustrate that metabolic flux can be significantly changed and directed into butanol or butyrate due to enhancement of NAD(P)H availability by controlling electron flow through the ferredoxin node.
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Affiliation(s)
- Feng Qi
- Department of BioSciences, Rice University, Houston, TX, 77005, USA.,Engineering Research Center of Industrial Microbiology of Ministry of Education, College of Life Sciences, Fujian Normal University, Fuzhou, 350117, Fujian, China.,Provincial University Key Laboratory of Cellular Stress Response and Metabolic Regulation, College of Life Sciences, Fujian Normal University, Fuzhou, 350117, Fujian, China
| | | | - Fayin Zhu
- Department of BioSciences, Rice University, Houston, TX, 77005, USA
| | - Matthew Pena
- Department of BioSciences, Rice University, Houston, TX, 77005, USA
| | - Ka-Yiu San
- Department of Bioengineering, Rice University, Houston, TX, 77005, USA.,Department of Chemical and Biomolecular Engineering, Rice University, Houston, TX, 77005, USA
| | - George N Bennett
- Department of BioSciences, Rice University, Houston, TX, 77005, USA. .,Department of Chemical and Biomolecular Engineering, Rice University, Houston, TX, 77005, USA.
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31
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Oehling V, Klaassen P, Frick O, Dusny C, Schmid A. l-Arabinose triggers its own uptake via induction of the arabinose-specific Gal2p transporter in an industrial Saccharomyces cerevisiae strain. BIOTECHNOLOGY FOR BIOFUELS 2018; 11:231. [PMID: 30159031 PMCID: PMC6106821 DOI: 10.1186/s13068-018-1231-8] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 06/06/2018] [Accepted: 08/17/2018] [Indexed: 06/08/2023]
Abstract
Bioethanol production processes with Saccharomyces cerevisiae using lignocellulosic biomass as feedstock are challenged by the simultaneous utilization of pentose and hexose sugars from biomass hydrolysates. The pentose uptake into the cell represents a crucial role for the efficiency of the process. The focus of the here presented study was to understand the uptake and conversion of the pentose l-arabinose in S. cerevisiae and reveal its regulation by d-glucose and d-galactose. Gal2p-the most prominent transporter enabling l-arabinose uptake in S. cerevisiae wild-type strains-has an affinity for the transport of l-arabinose, d-glucose, and d-galactose. d-Galactose was reported for being mandatory for inducing GAL2 expression. GAL2 expression is also known to be regulated by d-glucose-mediated carbon catabolite repression, as well as catabolite inactivation. The results of the present study demonstrate that l-arabinose can be used as sole carbon and energy source by the recombinant industrial strain S. cerevisiae DS61180. RT-qPCR and RNA-Seq experiments confirmed that l-arabinose can trigger its own uptake via the induction of GAL2 expression. Expression levels of GAL2 during growth on l-arabinose reached up to 21% of those obtained with d-galactose as sole carbon and energy source. l-Arabinose-induced GAL2 expression was also subject to catabolite repression by d-glucose. Kinetic investigations of substrate uptake, biomass, and product formation during growth on a mixture of d-glucose/l-arabinose revealed impairment of growth and ethanol production from l-arabinose upon d-glucose depletion. The presence of d-glucose is thus preventing the fermentation of l-arabinose in S. cerevisiae DS61180. Comparative transcriptome studies including the wild-type and a precursor strain delivered hints for an increased demand in ATP production and cofactor regeneration during growth of S. cerevisiae DS61180 on l-arabinose. Our results thus emphasize that cofactor and energy metabolism demand attention if the combined conversion of hexose and pentose sugars is intended, for example in biorefineries using lignocellulosics.
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Affiliation(s)
- Verena Oehling
- Laboratory of Chemical Biotechnology, Department of Biochemical & Chemical Engineering, TU Dortmund University, Dortmund, Germany
| | | | - Oliver Frick
- Laboratory of Chemical Biotechnology, Department of Biochemical & Chemical Engineering, TU Dortmund University, Dortmund, Germany
- Present Address: Department of Solar Materials, Helmholtz Centre for Environmental Research UFZ, Leipzig, Germany
| | - Christian Dusny
- Laboratory of Chemical Biotechnology, Department of Biochemical & Chemical Engineering, TU Dortmund University, Dortmund, Germany
- Present Address: Department of Solar Materials, Helmholtz Centre for Environmental Research UFZ, Leipzig, Germany
| | - Andreas Schmid
- Laboratory of Chemical Biotechnology, Department of Biochemical & Chemical Engineering, TU Dortmund University, Dortmund, Germany
- Present Address: Department of Solar Materials, Helmholtz Centre for Environmental Research UFZ, Leipzig, Germany
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32
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Mishra P, Lee NR, Lakshmanan M, Kim M, Kim BG, Lee DY. Genome-scale model-driven strain design for dicarboxylic acid production in Yarrowia lipolytica. BMC SYSTEMS BIOLOGY 2018; 12:12. [PMID: 29560822 PMCID: PMC5861505 DOI: 10.1186/s12918-018-0542-5] [Citation(s) in RCA: 44] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
Background Recently, there have been several attempts to produce long-chain dicarboxylic acids (DCAs) in various microbial hosts. Of these, Yarrowia lipolytica has great potential due to its oleaginous characteristics and unique ability to utilize hydrophobic substrates. However, Y. lipolytica should be further engineered to make it more competitive: the current approaches are mostly intuitive and cumbersome, thus limiting its industrial application. Results In this study, we proposed model-guided metabolic engineering strategies for enhanced production of DCAs in Y. lipolytica. At the outset, we reconstructed genome-scale metabolic model (GSMM) of Y. lipolytica (iYLI647) by substantially expanding the previous models. Subsequently, the model was validated using three sets of published culture experiment data. It was finally exploited to identify genetic engineering targets for overexpression, knockout, and cofactor modification by applying several in silico strain design methods, which potentially give rise to high yield production of the industrially relevant long-chain DCAs, e.g., dodecanedioic acid (DDDA). The resultant targets include (1) malate dehydrogenase and malic enzyme genes and (2) glutamate dehydrogenase gene, in silico overexpression of which generated additional NADPH required for fatty acid synthesis, leading to the increased DDDA fluxes by 48% and 22% higher, respectively, compared to wild-type. We further investigated the effect of supplying branched-chain amino acids on the acetyl-CoA turn-over rate which is key metabolite for fatty acid synthesis, suggesting their significance for production of DDDA in Y. lipolytica. Conclusion In silico model-based strain design strategies allowed us to identify several metabolic engineering targets for overproducing DCAs in lipid accumulating yeast, Y. lipolytica. Thus, the current study can provide a methodological framework that is applicable to other oleaginous yeasts for value-added biochemical production. Electronic supplementary material The online version of this article (10.1186/s12918-018-0542-5) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Pranjul Mishra
- NUS Synthetic Biology for Clinical and Technological Innovation (SynCTI), Life Sciences Institute, National University of Singapore, 28 Medical Drive, Singapore, 117456, Singapore
| | - Na-Rae Lee
- NUS Synthetic Biology for Clinical and Technological Innovation (SynCTI), Life Sciences Institute, National University of Singapore, 28 Medical Drive, Singapore, 117456, Singapore
| | - Meiyappan Lakshmanan
- Bioprocessing Technology Institute, Agency for Science, Technology and Research (A*STAR), 20 Biopolis Way, #06-01, Centros, Singapore, 138668, Singapore
| | - Minsuk Kim
- School of Chemical and Biological Engineering, Institute of Molecular Biology and Genetics, and Bioengineering Institute, Seoul National University, 1 Gwanak-ro, Gwanak-gu, Seoul, 151-742, Republic of Korea
| | - Byung-Gee Kim
- School of Chemical and Biological Engineering, Institute of Molecular Biology and Genetics, and Bioengineering Institute, Seoul National University, 1 Gwanak-ro, Gwanak-gu, Seoul, 151-742, Republic of Korea
| | - Dong-Yup Lee
- NUS Synthetic Biology for Clinical and Technological Innovation (SynCTI), Life Sciences Institute, National University of Singapore, 28 Medical Drive, Singapore, 117456, Singapore. .,Bioprocessing Technology Institute, Agency for Science, Technology and Research (A*STAR), 20 Biopolis Way, #06-01, Centros, Singapore, 138668, Singapore. .,School of Chemical Engineering, Sungkyunkwan University, 2066 Seobu-ro, Jangan-gu, Suwon, Gyeonggi-do, 16419, Republic of Korea.
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33
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Partow S, Hyland PB, Mahadevan R. Synthetic rescue couples NADPH generation to metabolite overproduction in Saccharomyces cerevisiae. Metab Eng 2017; 43:64-70. [PMID: 28803913 DOI: 10.1016/j.ymben.2017.08.004] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/18/2016] [Revised: 08/04/2017] [Accepted: 08/07/2017] [Indexed: 11/15/2022]
Abstract
Engineering the redox cofactor metabolism is known to be a key challenge in developing a platform strain for biosynthesis of valuable products. Hence, general strategies for manipulation of co-factor metabolism in industrially relevant hosts are of significance. Here, we demonstrate an improvement in α-ketoglutarate (AKG) production in S. cerevisiae using a novel approach based on synthetic rescue. Here, we first perturb the cytosolic NADPH metabolism via deletion of glucose-6-phosphate dehydrogenase (ZWF1). In parallel, we used a strain design algorithm to identify strategies for further improvement in AKG production. Implementation of the identified genetic targets, including disruption of succinyl-CoA Ligase (LSC2) and constitutive expression of NADP+-specific isocitrate dehydrogenases (IDP1 and IDP2) resulted in more than 3 fold improvement in AKG production as compared to the wild type. Our results demonstrate this improvement is due to a synthetic rescue mechanism in which the metabolic flux was redirected towards AKG production through the manipulation of redox cofactors. Disrupting lsc2 in zwf1 mutant improved specific growth rate more than 15% as compared to the zwf1 mutant. In addition, our result suggests that cytosolic isocitrate dehydrogenase (IDP2) may be regulated by isocitrate pools. Together, these results suggest the ability to improve metabolite production via a model guided synthetic rescue mechanism in S. cerevisiae and the potential for using IDP2 expression as a generalized strategy to effectively meet NADPH requirements in engineered strains.
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Affiliation(s)
- Siavash Partow
- Department of Chemical Engineering and Applied Chemistry, University of Toronto, Canada
| | - Patrick B Hyland
- Department of Chemical Engineering and Applied Chemistry, University of Toronto, Canada
| | - Radhakrishnan Mahadevan
- Department of Chemical Engineering and Applied Chemistry, University of Toronto, Canada; Institute of Biomaterials and Biomedical Engineering (IBBME), University of Toronto, Canada.
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34
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Zhao C, Zhao Q, Li Y, Zhang Y. Engineering redox homeostasis to develop efficient alcohol-producing microbial cell factories. Microb Cell Fact 2017; 16:115. [PMID: 28646866 PMCID: PMC5483285 DOI: 10.1186/s12934-017-0728-3] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/24/2017] [Accepted: 06/16/2017] [Indexed: 12/11/2022] Open
Abstract
The biosynthetic pathways of most alcohols are linked to intracellular redox homeostasis, which is crucial for life. This crucial balance is primarily controlled by the generation of reducing equivalents, as well as the (reduction)-oxidation metabolic cycle and the thiol redox homeostasis system. As a main oxidation pathway of reducing equivalents, the biosynthesis of most alcohols includes redox reactions, which are dependent on cofactors such as NADH or NADPH. Thus, when engineering alcohol-producing strains, the availability of cofactors and redox homeostasis must be considered. In this review, recent advances on the engineering of cellular redox homeostasis systems to accelerate alcohol biosynthesis are summarized. Recent approaches include improving cofactor availability, manipulating the affinity of redox enzymes to specific cofactors, as well as globally controlling redox reactions, indicating the power of these approaches, and opening a path towards improving the production of a number of different industrially-relevant alcohols in the near future.
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Affiliation(s)
- Chunhua Zhao
- CAS Key Laboratory of Microbial Physiological and Metabolic Engineering, Institute of Microbiology, Chinese Academy of Sciences, No. 1 West Beichen Road Chaoyang District, Beijing, 100101 China
- University of Chinese Academy of Sciences, Beijing, 100049 China
| | - Qiuwei Zhao
- CAS Key Laboratory of Microbial Physiological and Metabolic Engineering, Institute of Microbiology, Chinese Academy of Sciences, No. 1 West Beichen Road Chaoyang District, Beijing, 100101 China
| | - Yin Li
- CAS Key Laboratory of Microbial Physiological and Metabolic Engineering, Institute of Microbiology, Chinese Academy of Sciences, No. 1 West Beichen Road Chaoyang District, Beijing, 100101 China
| | - Yanping Zhang
- CAS Key Laboratory of Microbial Physiological and Metabolic Engineering, Institute of Microbiology, Chinese Academy of Sciences, No. 1 West Beichen Road Chaoyang District, Beijing, 100101 China
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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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Weber N, Hatsch A, Labagnere L, Heider H. Production of (S)-2-aminobutyric acid and (S)-2-aminobutanol in Saccharomyces cerevisiae. Microb Cell Fact 2017; 16:51. [PMID: 28335772 PMCID: PMC5364695 DOI: 10.1186/s12934-017-0667-z] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/10/2016] [Accepted: 03/21/2017] [Indexed: 01/09/2023] Open
Abstract
Background Saccharomyces cerevisiae (baker’s yeast) has great potential as a whole-cell biocatalyst for multistep synthesis of various organic molecules. To date, however, few examples exist in the literature of the successful biosynthetic production of chemical compounds, in yeast, that do not exist in nature. Considering that more than 30% of all drugs on the market are purely chemical compounds, often produced by harsh synthetic chemistry or with very low yields, novel and environmentally sound production routes are highly desirable. Here, we explore the biosynthetic production of enantiomeric precursors of the anti-tuberculosis and anti-epilepsy drugs ethambutol, brivaracetam, and levetiracetam. To this end, we have generated heterologous biosynthetic pathways leading to the production of (S)-2-aminobutyric acid (ABA) and (S)-2-aminobutanol in baker’s yeast. Results We first designed a two-step heterologous pathway, starting with the endogenous amino acid l-threonine and leading to the production of enantiopure (S)-2-aminobutyric acid. The combination of Bacillus subtilis threonine deaminase and a mutated Escherichia coli glutamate dehydrogenase resulted in the intracellular accumulation of 0.40 mg/L of (S)-2-aminobutyric acid. The combination of a threonine deaminase from Solanum lycopersicum (tomato) with two copies of mutated glutamate dehydrogenase from E. coli resulted in the accumulation of comparable amounts of (S)-2-aminobutyric acid. Additional l-threonine feeding elevated (S)-2-aminobutyric acid production to more than 1.70 mg/L. Removing feedback inhibition of aspartate kinase HOM3, an enzyme involved in threonine biosynthesis in yeast, elevated (S)-2-aminobutyric acid biosynthesis to above 0.49 mg/L in cultures not receiving additional l-threonine. We ultimately extended the pathway from (S)-2-aminobutyric acid to (S)-2-aminobutanol by introducing two reductases and a phosphopantetheinyl transferase. The engineered strains produced up to 1.10 mg/L (S)-2-aminobutanol. Conclusions Our results demonstrate the biosynthesis of (S)-2-aminobutyric acid and (S)-2-aminobutanol in yeast. To our knowledge this is the first time that the purely synthetic compound (S)-2-aminobutanol has been produced in vivo. This work paves the way to greener and more sustainable production of chemical entities hitherto inaccessible to synthetic biology. Electronic supplementary material The online version of this article (doi:10.1186/s12934-017-0667-z) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Nora Weber
- Evolva SA, Duggingerstrasse 23, 4153, Reinach, Switzerland.
| | - Anaëlle Hatsch
- Evolva SA, Duggingerstrasse 23, 4153, Reinach, Switzerland
| | | | - Harald Heider
- Evolva SA, Duggingerstrasse 23, 4153, Reinach, Switzerland
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Zhang GC, Turner TL, Jin YS. Enhanced xylose fermentation by engineered yeast expressing NADH oxidase through high cell density inoculums. ACTA ACUST UNITED AC 2017; 44:387-395. [DOI: 10.1007/s10295-016-1899-3] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/28/2016] [Accepted: 12/25/2016] [Indexed: 12/22/2022]
Abstract
Abstract
Accumulation of reduced byproducts such as glycerol and xylitol during xylose fermentation by engineered Saccharomyces cerevisiae hampers the economic production of biofuels and chemicals from cellulosic hydrolysates. In particular, engineered S. cerevisiae expressing NADPH-linked xylose reductase (XR) and NAD+-linked xylitol dehydrogenase (XDH) produces substantial amounts of the reduced byproducts under anaerobic conditions due to the cofactor difference of XR and XDH. While the additional expression of a water-forming NADH oxidase (NoxE) from Lactococcus lactis in engineered S. cerevisiae with the XR/XDH pathway led to reduced glycerol and xylitol production and increased ethanol yields from xylose, volumetric ethanol productivities by the engineered yeast decreased because of growth defects from the overexpression of noxE. In this study, we introduced noxE into an engineered yeast strain (SR8) exhibiting near-optimal xylose fermentation capacity. To overcome the growth defect caused by the overexpression of noxE, we used a high cell density inoculum for xylose fermentation by the SR8 expressing noxE. The resulting strain, SR8N, not only showed a higher ethanol yield and lower byproduct yields, but also exhibited a high ethanol productivity during xylose fermentation. As noxE overexpression elicits a negligible growth defect on glucose conditions, the beneficial effects of noxE overexpression were substantial when a mixture of glucose and xylose was used. Consumption of glucose led to rapid cell growth and therefore enhanced the subsequent xylose fermentation. As a result, the SR8N strain produced more ethanol and fewer byproducts from a mixture of glucose and xylose than the parental SR8 strain without noxE overexpression. Our results suggest that the growth defects from noxE overexpression can be overcome in the case of fermenting lignocellulose-derived sugars such as glucose and xylose.
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Affiliation(s)
- Guo-Chang Zhang
- grid.35403.31 0000000419369991 Carl R. Woese Institute for Genomic Biology University of Illinois at Urbana-Champaign 1206 W. Gregory Drive 61801 Urbana IL USA
- grid.35403.31 0000000419369991 Department of Food Science and Human Nutrition University of Illinois at Urbana-Champaign 61801 Urbana IL USA
| | - Timothy L Turner
- grid.35403.31 0000000419369991 Department of Food Science and Human Nutrition University of Illinois at Urbana-Champaign 61801 Urbana IL USA
| | - Yong-Su Jin
- grid.35403.31 0000000419369991 Carl R. Woese Institute for Genomic Biology University of Illinois at Urbana-Champaign 1206 W. Gregory Drive 61801 Urbana IL USA
- grid.35403.31 0000000419369991 Department of Food Science and Human Nutrition University of Illinois at Urbana-Champaign 61801 Urbana IL USA
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Cahn JKB, Werlang CA, Baumschlager A, Brinkmann-Chen S, Mayo SL, Arnold FH. A General Tool for Engineering the NAD/NADP Cofactor Preference of Oxidoreductases. ACS Synth Biol 2017; 6:326-333. [PMID: 27648601 DOI: 10.1021/acssynbio.6b00188] [Citation(s) in RCA: 98] [Impact Index Per Article: 14.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
The ability to control enzymatic nicotinamide cofactor utilization is critical for engineering efficient metabolic pathways. However, the complex interactions that determine cofactor-binding preference render this engineering particularly challenging. Physics-based models have been insufficiently accurate and blind directed evolution methods too inefficient to be widely adopted. Building on a comprehensive survey of previous studies and our own prior engineering successes, we present a structure-guided, semirational strategy for reversing enzymatic nicotinamide cofactor specificity. This heuristic-based approach leverages the diversity and sensitivity of catalytically productive cofactor binding geometries to limit the problem to an experimentally tractable scale. We demonstrate the efficacy of this strategy by inverting the cofactor specificity of four structurally diverse NADP-dependent enzymes: glyoxylate reductase, cinnamyl alcohol dehydrogenase, xylose reductase, and iron-containing alcohol dehydrogenase. The analytical components of this approach have been fully automated and are available in the form of an easy-to-use web tool: Cofactor Specificity Reversal-Structural Analysis and Library Design (CSR-SALAD).
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Affiliation(s)
- Jackson K. B. Cahn
- Division of Chemistry and Chemical Engineering, and ‡Division of Biology and Biological
Engineering, California Institute of Technology, Pasadena, California 91125, United States
| | - Caroline A. Werlang
- Division of Chemistry and Chemical Engineering, and ‡Division of Biology and Biological
Engineering, California Institute of Technology, Pasadena, California 91125, United States
| | - Armin Baumschlager
- Division of Chemistry and Chemical Engineering, and ‡Division of Biology and Biological
Engineering, California Institute of Technology, Pasadena, California 91125, United States
| | - Sabine Brinkmann-Chen
- Division of Chemistry and Chemical Engineering, and ‡Division of Biology and Biological
Engineering, California Institute of Technology, Pasadena, California 91125, United States
| | - Stephen L. Mayo
- Division of Chemistry and Chemical Engineering, and ‡Division of Biology and Biological
Engineering, California Institute of Technology, Pasadena, California 91125, United States
| | - Frances H. Arnold
- Division of Chemistry and Chemical Engineering, and ‡Division of Biology and Biological
Engineering, California Institute of Technology, Pasadena, California 91125, United States
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Guo W, Sheng J, Feng X. Synergizing 13C Metabolic Flux Analysis and Metabolic Engineering for Biochemical Production. ADVANCES IN BIOCHEMICAL ENGINEERING/BIOTECHNOLOGY 2017; 162:265-299. [PMID: 28424826 DOI: 10.1007/10_2017_2] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
Metabolic engineering of industrial microorganisms to produce chemicals, fuels, and drugs has attracted increasing interest as it provides an environment-friendly and renewable route that does not depend on depleting petroleum sources. However, the microbial metabolism is so complex that metabolic engineering efforts often have difficulty in achieving a satisfactory yield, titer, or productivity of the target chemical. To overcome this challenge, 13C Metabolic Flux Analysis (13C-MFA) has been developed to investigate rigorously the cell metabolism and quantify the carbon flux distribution in central metabolic pathways. In the past decade, 13C-MFA has been widely used in academic labs and the biotechnology industry to pinpoint the key issues related to microbial-based chemical production and to guide the development of the appropriate metabolic engineering strategies for improving the biochemical production. In this chapter we introduce the basics of 13C-MFA and illustrate how 13C-MFA has been applied to synergize with metabolic engineering to identify and tackle the rate-limiting steps in biochemical production.
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Affiliation(s)
- Weihua Guo
- Department of Biological Systems Engineering, Virginia Polytechnic Institute and State University, Blacksburg, VA, 24061, USA
| | - Jiayuan Sheng
- Department of Biological Systems Engineering, Virginia Polytechnic Institute and State University, Blacksburg, VA, 24061, USA
| | - Xueyang Feng
- Department of Biological Systems Engineering, Virginia Polytechnic Institute and State University, Blacksburg, VA, 24061, USA.
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Li F, Li Y, Sun L, Li X, Yin C, An X, Chen X, Tian Y, Song H. Engineering Shewanella oneidensis enables xylose-fed microbial fuel cell. BIOTECHNOLOGY FOR BIOFUELS 2017; 10:196. [PMID: 28804512 PMCID: PMC5549365 DOI: 10.1186/s13068-017-0881-2] [Citation(s) in RCA: 43] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/26/2017] [Accepted: 08/01/2017] [Indexed: 05/22/2023]
Abstract
BACKGROUND The microbial fuel cell (MFC) is a green and sustainable technology for electricity energy harvest from biomass, in which exoelectrogens use metabolism and extracellular electron transfer pathways for the conversion of chemical energy into electricity. However, Shewanella oneidensis MR-1, one of the most well-known exoelectrogens, could not use xylose (a key pentose derived from hydrolysis of lignocellulosic biomass) for cell growth and power generation, which limited greatly its practical applications. RESULTS Herein, to enable S. oneidensis to directly utilize xylose as the sole carbon source for bioelectricity production in MFCs, we used synthetic biology strategies to successfully construct four genetically engineered S. oneidensis (namely XE, GE, XS, and GS) by assembling one of the xylose transporters (from Candida intermedia and Clostridium acetobutylicum) with one of intracellular xylose metabolic pathways (the isomerase pathway from Escherichia coli and the oxidoreductase pathway from Scheffersomyces stipites), respectively. We found that among these engineered S. oneidensis strains, the strain GS (i.e. harbouring Gxf1 gene encoding the xylose facilitator from C. intermedi, and XYL1, XYL2, and XKS1 genes encoding the xylose oxidoreductase pathway from S. stipites) was able to generate the highest power density, enabling a maximum electricity power density of 2.1 ± 0.1 mW/m2. CONCLUSION To the best of our knowledge, this was the first report on the rationally designed Shewanella that could use xylose as the sole carbon source and electron donor to produce electricity. The synthetic biology strategies developed in this study could be further extended to rationally engineer other exoelectrogens for lignocellulosic biomass utilization to generate electricity power.
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Affiliation(s)
- Feng Li
- Key Laboratory of Systems Bioengineering (Ministry of Education), School of Chemical Engineering and Technology, Tianjin University, Tianjin, 300072 China
- SynBio Research Platform, Collaborative Innovation Centre of Chemical Science and Engineering, Tianjin University, Tianjin, 300072 China
| | - Yuanxiu Li
- Key Laboratory of Systems Bioengineering (Ministry of Education), School of Chemical Engineering and Technology, Tianjin University, Tianjin, 300072 China
- SynBio Research Platform, Collaborative Innovation Centre of Chemical Science and Engineering, Tianjin University, Tianjin, 300072 China
| | - Liming Sun
- Petrochemical Research Institute, PetroChina Company Limited, Beijing, 102206 People’s Republic of China
| | - Xiaofei Li
- Key Laboratory of Systems Bioengineering (Ministry of Education), School of Chemical Engineering and Technology, Tianjin University, Tianjin, 300072 China
- SynBio Research Platform, Collaborative Innovation Centre of Chemical Science and Engineering, Tianjin University, Tianjin, 300072 China
| | - Changji Yin
- Key Laboratory of Systems Bioengineering (Ministry of Education), School of Chemical Engineering and Technology, Tianjin University, Tianjin, 300072 China
- SynBio Research Platform, Collaborative Innovation Centre of Chemical Science and Engineering, Tianjin University, Tianjin, 300072 China
| | - Xingjuan An
- Key Laboratory of Systems Bioengineering (Ministry of Education), School of Chemical Engineering and Technology, Tianjin University, Tianjin, 300072 China
- SynBio Research Platform, Collaborative Innovation Centre of Chemical Science and Engineering, Tianjin University, Tianjin, 300072 China
| | - Xiaoli Chen
- Key Laboratory of Systems Bioengineering (Ministry of Education), School of Chemical Engineering and Technology, Tianjin University, Tianjin, 300072 China
- SynBio Research Platform, Collaborative Innovation Centre of Chemical Science and Engineering, Tianjin University, Tianjin, 300072 China
| | - Yao Tian
- Key Laboratory of Systems Bioengineering (Ministry of Education), School of Chemical Engineering and Technology, Tianjin University, Tianjin, 300072 China
- SynBio Research Platform, Collaborative Innovation Centre of Chemical Science and Engineering, Tianjin University, Tianjin, 300072 China
| | - Hao Song
- Key Laboratory of Systems Bioengineering (Ministry of Education), School of Chemical Engineering and Technology, Tianjin University, Tianjin, 300072 China
- SynBio Research Platform, Collaborative Innovation Centre of Chemical Science and Engineering, Tianjin University, Tianjin, 300072 China
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Isolation and characterization of xylitol-assimilating mutants of recombinant Saccharomyces cerevisiae. J Biosci Bioeng 2016; 122:446-55. [DOI: 10.1016/j.jbiosc.2016.03.008] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/07/2015] [Revised: 02/22/2016] [Accepted: 03/12/2016] [Indexed: 11/22/2022]
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Zhang GC, Kong II, Wei N, Peng D, Turner TL, Sung BH, Sohn JH, Jin YS. Optimization of an acetate reduction pathway for producing cellulosic ethanol by engineered yeast. Biotechnol Bioeng 2016; 113:2587-2596. [DOI: 10.1002/bit.26021] [Citation(s) in RCA: 37] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/06/2016] [Revised: 05/24/2016] [Accepted: 05/27/2016] [Indexed: 01/17/2023]
Affiliation(s)
- Guo-Chang Zhang
- Carl R. Woese Institute for Genomic Biology; University of Illinois at Urbana-Champaign; Urbana Illinois 61801
- Department of Food Science and Human Nutrition; University of Illinois at Urbana-Champaign; Urbana Illinois
| | - In Iok Kong
- Carl R. Woese Institute for Genomic Biology; University of Illinois at Urbana-Champaign; Urbana Illinois 61801
- Department of Food Science and Human Nutrition; University of Illinois at Urbana-Champaign; Urbana Illinois
| | - Na Wei
- Department of Civil and Environmental Engineering and Earth Sciences; University of Notre Dame; South Bend Indiana
| | - Dairong Peng
- Department of Food Science and Human Nutrition; University of Illinois at Urbana-Champaign; Urbana Illinois
| | - Timothy L. Turner
- Department of Food Science and Human Nutrition; University of Illinois at Urbana-Champaign; Urbana Illinois
| | - Bong Hyun Sung
- Bioenergy and Biochemical Research Center; Korea Research Institute of Bioscience and Biotechnology; Daejeon Korea
| | - Jung-Hoon Sohn
- Bioenergy and Biochemical Research Center; Korea Research Institute of Bioscience and Biotechnology; Daejeon Korea
| | - Yong-Su Jin
- Carl R. Woese Institute for Genomic Biology; University of Illinois at Urbana-Champaign; Urbana Illinois 61801
- Department of Food Science and Human Nutrition; University of Illinois at Urbana-Champaign; Urbana Illinois
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Ye W, Zhang W, Liu T, Tan G, Li H, Huang Z. Improvement of Ethanol Production in Saccharomyces cerevisiae by High-Efficient Disruption of the ADH2 Gene Using a Novel Recombinant TALEN Vector. Front Microbiol 2016; 7:1067. [PMID: 27462304 PMCID: PMC4939295 DOI: 10.3389/fmicb.2016.01067] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/11/2016] [Accepted: 06/24/2016] [Indexed: 01/28/2023] Open
Abstract
Bioethanol is becoming increasingly important in energy supply and economic development. However, the low yield of bioethanol and the insufficiency of high-efficient genetic manipulation approaches limit its application. In this study, a novel transcription activator-like effector nuclease (TALEN) vector containing the left and right arms of TALEN was electroporated into Saccharomyces cerevisiae strain As2.4 to sequence the alcohol dehydrogenase gene ADH2 and the hygromycin-resistant gene hyg. Western blot analysis using anti-FLAG monoclonal antibody proved the successful expression of TALE proteins in As2.4 strains. qPCR and sequencing demonstrated the accurate knockout of the 17 bp target gene with 80% efficiency. The TALEN vector and ADH2 PCR product were electroporated into ΔADH2 to complement the ADH2 gene (ADH2+ As2.4). LC–MS and GC were employed to detect ethanol yields in the native As2.4, ΔADH2 As2.4, and ADH2+ As2.4 strains. Results showed that ethanol production was improved by 52.4 ± 5.3% through the disruption of ADH2 in As2.4. The bioethanol yield of ADH2+ As2.4 was nearly the same as that of native As2.4. This study is the first to report on the disruption of a target gene in S. cerevisiae by employing Fast TALEN technology to improve bioethanol yield. This work provides a novel approach for the disruption of a target gene in S. cerevisiae with high efficiency and specificity, thereby promoting the improvement of bioethanol production in S. cerevisiae by metabolic engineering.
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Affiliation(s)
- Wei Ye
- State Key Laboratory of Applied Microbiology Southern China, Guangdong Provincial Key Laboratory of Microbial Culture Collection and Application, Guangdong Open Laboratory of Applied Micrbiology, Guangdong Institute of Microbiology Guangzhou, China
| | - Weimin Zhang
- State Key Laboratory of Applied Microbiology Southern China, Guangdong Provincial Key Laboratory of Microbial Culture Collection and Application, Guangdong Open Laboratory of Applied Micrbiology, Guangdong Institute of Microbiology Guangzhou, China
| | - Taomei Liu
- State Key Laboratory of Applied Microbiology Southern China, Guangdong Provincial Key Laboratory of Microbial Culture Collection and Application, Guangdong Open Laboratory of Applied Micrbiology, Guangdong Institute of Microbiology Guangzhou, China
| | - Guohui Tan
- State Key Laboratory of Applied Microbiology Southern China, Guangdong Provincial Key Laboratory of Microbial Culture Collection and Application, Guangdong Open Laboratory of Applied Micrbiology, Guangdong Institute of Microbiology Guangzhou, China
| | - Haohua Li
- State Key Laboratory of Applied Microbiology Southern China, Guangdong Provincial Key Laboratory of Microbial Culture Collection and Application, Guangdong Open Laboratory of Applied Micrbiology, Guangdong Institute of Microbiology Guangzhou, China
| | - Zilei Huang
- State Key Laboratory of Applied Microbiology Southern China, Guangdong Provincial Key Laboratory of Microbial Culture Collection and Application, Guangdong Open Laboratory of Applied Micrbiology, Guangdong Institute of Microbiology Guangzhou, China
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45
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Nielsen F, Zacchi G, Galbe M, Wallberg O. Prefermentation improves ethanol yield in separate hydrolysis and cofermentation of steam-pretreated wheat straw. ACTA ACUST UNITED AC 2016. [DOI: 10.1186/s40508-016-0054-9] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
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46
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47
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Jo SE, Seong YJ, Lee HS, Lee SM, Kim SJ, Park K, Park YC. Microaerobic conversion of xylose to ethanol in recombinant Saccharomyces cerevisiae SX6 MUT expressing cofactor-balanced xylose metabolic enzymes and deficient in ALD6. J Biotechnol 2016; 227:72-78. [DOI: 10.1016/j.jbiotec.2016.04.005] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/05/2016] [Revised: 03/27/2016] [Accepted: 04/04/2016] [Indexed: 11/30/2022]
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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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13C-Metabolic Flux Analysis: An Accurate Approach to Demystify Microbial Metabolism for Biochemical Production. Bioengineering (Basel) 2015; 3:bioengineering3010003. [PMID: 28952565 PMCID: PMC5597161 DOI: 10.3390/bioengineering3010003] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/01/2015] [Revised: 12/10/2015] [Accepted: 12/18/2015] [Indexed: 12/15/2022] Open
Abstract
Metabolic engineering of various industrial microorganisms to produce chemicals, fuels, and drugs has raised interest since it is environmentally friendly, sustainable, and independent of nonrenewable resources. However, microbial metabolism is so complex that only a few metabolic engineering efforts have been able to achieve a satisfactory yield, titer or productivity of the target chemicals for industrial commercialization. In order to overcome this challenge, 13C Metabolic Flux Analysis (13C-MFA) has been continuously developed and widely applied to rigorously investigate cell metabolism and quantify the carbon flux distribution in central metabolic pathways. In the past decade, many 13C-MFA studies have been performed in academic labs and biotechnology industries to pinpoint key issues related to microbe-based chemical production. Insightful information about the metabolic rewiring has been provided to guide the development of the appropriate metabolic engineering strategies for improving the biochemical production. In this review, we will introduce the basics of 13C-MFA and illustrate how 13C-MFA has been applied via integration with metabolic engineering to identify and tackle the rate-limiting steps in biochemical production for various host microorganisms
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In Silico Constraint-Based Strain Optimization Methods: the Quest for Optimal Cell Factories. Microbiol Mol Biol Rev 2015; 80:45-67. [PMID: 26609052 DOI: 10.1128/mmbr.00014-15] [Citation(s) in RCA: 75] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023] Open
Abstract
Shifting from chemical to biotechnological processes is one of the cornerstones of 21st century industry. The production of a great range of chemicals via biotechnological means is a key challenge on the way toward a bio-based economy. However, this shift is occurring at a pace slower than initially expected. The development of efficient cell factories that allow for competitive production yields is of paramount importance for this leap to happen. Constraint-based models of metabolism, together with in silico strain design algorithms, promise to reveal insights into the best genetic design strategies, a step further toward achieving that goal. In this work, a thorough analysis of the main in silico constraint-based strain design strategies and algorithms is presented, their application in real-world case studies is analyzed, and a path for the future is discussed.
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