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Huang J, Wang X, Chen X, Li H, Chen Y, Hu Z, Yang S. Adaptive Laboratory Evolution and Metabolic Engineering of Zymomonas mobilis for Bioethanol Production Using Molasses. ACS Synth Biol 2023; 12:1297-1307. [PMID: 37036829 DOI: 10.1021/acssynbio.3c00056] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 04/11/2023]
Abstract
Molasses with abundant sugars is widely used for bioethanol production. Although the ethanologenic bacterium Zymomonas mobilis can use glucose, fructose, and sucrose for ethanol production, levan production from sucrose reduces the ethanol yield of molasses fermentation. To increase ethanol production from sucrose-rich molasses, Z. mobilis was adapted in molasses, sucrose, and fructose in parallel. Adaptation in fructose is the most effective route to generate an evolved strain F74 with improved molasses utilization, which is majorly due to a G99S mutation in Glf for enhanced fructose import. Subsequent sacB deletion and sacC overexpression in F74 to divert sucrose metabolism from levan production to ethanol production further enhanced ethanol productivity 28.6% to 1.35 g/L/h. The efficient utilization of molasses by diverting sucrose metabolic flux through adaptation and genome engineering not only generated an excellent ethanol producer using molasses but also provided the strategy for developing microbial cell factories.
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Affiliation(s)
- Ju Huang
- State Key Laboratory of Biocatalysis and Enzyme Engineering, and School of Life Sciences, Hubei University, Wuhan 430062, China
| | - Xia Wang
- State Key Laboratory of Biocatalysis and Enzyme Engineering, and School of Life Sciences, Hubei University, Wuhan 430062, China
| | - Xiangyu Chen
- State Key Laboratory of Biocatalysis and Enzyme Engineering, and School of Life Sciences, Hubei University, Wuhan 430062, China
| | - Han Li
- State Key Laboratory of Biocatalysis and Enzyme Engineering, and School of Life Sciences, Hubei University, Wuhan 430062, China
| | - Yunhao Chen
- State Key Laboratory of Biocatalysis and Enzyme Engineering, and School of Life Sciences, Hubei University, Wuhan 430062, China
| | - Zhousheng Hu
- State Key Laboratory of Biocatalysis and Enzyme Engineering, and School of Life Sciences, Hubei University, Wuhan 430062, China
| | - Shihui Yang
- State Key Laboratory of Biocatalysis and Enzyme Engineering, and School of Life Sciences, Hubei University, Wuhan 430062, China
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2
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Zhang K, Zhang W, Qin M, Li Y, Wang H. Characterization and Application of the Sugar Transporter Zmo0293 from Zymomonas mobilis. Int J Mol Sci 2023; 24:ijms24065888. [PMID: 36982961 PMCID: PMC10055971 DOI: 10.3390/ijms24065888] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/03/2023] [Revised: 03/15/2023] [Accepted: 03/19/2023] [Indexed: 03/30/2023] Open
Abstract
Zymomonas mobilis is a natural ethanologen with many desirable characteristics, which makes it an ideal industrial microbial biocatalyst for the commercial production of desirable bioproducts. Sugar transporters are responsible for the import of substrate sugars and the conversion of ethanol and other products. Glucose-facilitated diffusion protein Glf is responsible for facilitating the diffusion of glucose uptake in Z. mobilis. However, another sugar transporter-encoded gene, ZMO0293, is poorly characterized. We employed gene deletion and heterologous expression mediated by the CRISPR/Cas method to investigate the role of ZMO0293. The results showed that deletion of the ZMO0293 gene slowed growth and reduced ethanol production and the activities of key enzymes involved in glucose metabolism in the presence of high concentrations of glucose. Moreover, ZMO0293 deletion caused different transcriptional changes in some genes of the Entner Doudoroff (ED) pathway in the ZM4-ΔZM0293 strain but not in ZM4 cells. The integrated expression of ZMO0293 restored the growth of the glucose uptake-defective strain Escherichia coli BL21(DE3)-ΔptsG. This study reveals the function of the ZMO0293 gene in Z. mobilis in response to high concentrations of glucose and provides a new biological part for synthetic biology.
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Affiliation(s)
- Kun Zhang
- Henan Province Engineering Laboratory for Bioconversion Technology of Functional Microbes, College of Life Sciences, Henan Normal University, Xinxiang 453007, China
| | - Wenwen Zhang
- Henan Province Engineering Laboratory for Bioconversion Technology of Functional Microbes, College of Life Sciences, Henan Normal University, Xinxiang 453007, China
| | - Mengxing Qin
- Henan Province Engineering Laboratory for Bioconversion Technology of Functional Microbes, College of Life Sciences, Henan Normal University, Xinxiang 453007, China
| | - Yi Li
- Henan Province Engineering Laboratory for Bioconversion Technology of Functional Microbes, College of Life Sciences, Henan Normal University, Xinxiang 453007, China
| | - Hailei Wang
- Henan Province Engineering Laboratory for Bioconversion Technology of Functional Microbes, College of Life Sciences, Henan Normal University, Xinxiang 453007, China
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3
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Joshi A, Verma KK, D Rajput V, Minkina T, Arora J. Recent advances in metabolic engineering of microorganisms for advancing lignocellulose-derived biofuels. Bioengineered 2022; 13:8135-8163. [PMID: 35297313 PMCID: PMC9161965 DOI: 10.1080/21655979.2022.2051856] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023] Open
Abstract
Combating climate change and ensuring energy supply to a rapidly growing global population has highlighted the need to replace petroleum fuels with clean, and sustainable renewable fuels. Biofuels offer a solution to safeguard energy security with reduced ecological footprint and process economics. Over the past years, lignocellulosic biomass has become the most preferred raw material for the production of biofuels, such as fuel, alcohol, biodiesel, and biohydrogen. However, the cost-effective conversion of lignocellulose into biofuels remains an unsolved challenge at the industrial scale. Recently, intensive efforts have been made in lignocellulose feedstock and microbial engineering to address this problem. By improving the biological pathways leading to the polysaccharide, lignin, and lipid biosynthesis, limited success has been achieved, and still needs to improve sustainable biofuel production. Impressive success is being achieved by the retouring metabolic pathways of different microbial hosts. Several robust phenotypes, mostly from bacteria and yeast domains, have been successfully constructed with improved substrate spectrum, product yield and sturdiness against hydrolysate toxins. Cyanobacteria is also being explored for metabolic advancement in recent years, however, it also remained underdeveloped to generate commercialized biofuels. The bacterium Escherichia coli and yeast Saccharomyces cerevisiae strains are also being engineered to have cell surfaces displaying hydrolytic enzymes, which holds much promise for near-term scale-up and biorefinery use. Looking forward, future advances to achieve economically feasible production of lignocellulosic-based biofuels with special focus on designing more efficient metabolic pathways coupled with screening, and engineering of novel enzymes.
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Affiliation(s)
- Abhishek Joshi
- Laboratory of Biomolecular Technology, Department of Botany, Mohanlal Sukhadia University, Udaipur313001, India
| | - Krishan K. Verma
- Key Laboratory of Sugarcane Biotechnology and Genetic Improvement (Guangxi), Ministry of Agriculture and Rural Affairs/Guangxi Key Laboratory of Sugarcane Genetic improvement/Sugarcane Research Institute, Guangxi Academy of Agricultural Sciences, Nanning - 530007, China
| | - Vishnu D Rajput
- Academy of Biology and Biotechnology, Southern Federal University, 344090, Russia
| | - Tatiana Minkina
- Academy of Biology and Biotechnology, Southern Federal University, 344090, Russia
| | - Jaya Arora
- Laboratory of Biomolecular Technology, Department of Botany, Mohanlal Sukhadia University, Udaipur313001, India,CONTACT Jaya Arora Laboratory of Biomolecular Technology, Department of Botany, Mohanlal Sukhadia University, Udaipur313001, India
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4
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Jenkins Sánchez LR, Claus S, Muth LT, Salvador López JM, Van Bogaert I. Force in numbers: high-throughput screening approaches to unlock microbial transport. Curr Opin Biotechnol 2021; 74:204-210. [PMID: 34968868 DOI: 10.1016/j.copbio.2021.11.012] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/29/2021] [Revised: 11/19/2021] [Accepted: 11/24/2021] [Indexed: 11/18/2022]
Abstract
Biological membranes are inherently complex, making transport processes in microbial cell factories a significant bottleneck. Lack of knowledge on transport proteins' characteristics and the need for advanced technical equipment often hamper transporter identification and optimization. For these reasons, moving away from individual characterization and towards high-throughput mining, engineering, and screening of transporters is an increasingly attractive approach. Superior transporters can be selected from large libraries by coupling their activity to growth, for substrates that function as feedstocks or toxic compounds. Other compounds can be screened thanks to recent advances in the design and deployment of synthetic genetic circuits (biosensors). Furthermore, novel strategies are rapidly increasing the repertoire of biomolecule transporters susceptible to high-throughput selection methods.
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Affiliation(s)
- Liam Richard Jenkins Sánchez
- Centre for Synthetic Biology, Department of Biotechnology, Ghent University, Coupure Links 653, Ghent, 9000, Belgium
| | - Silke Claus
- Centre for Synthetic Biology, Department of Biotechnology, Ghent University, Coupure Links 653, Ghent, 9000, Belgium
| | - Liv Teresa Muth
- Centre for Synthetic Biology, Department of Biotechnology, Ghent University, Coupure Links 653, Ghent, 9000, Belgium
| | - José Manuel Salvador López
- Centre for Synthetic Biology, Department of Biotechnology, Ghent University, Coupure Links 653, Ghent, 9000, Belgium
| | - Inge Van Bogaert
- Centre for Synthetic Biology, Department of Biotechnology, Ghent University, Coupure Links 653, Ghent, 9000, Belgium.
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Kurgan G, Onyeabor M, Holland SC, Taylor E, Schneider A, Kurgan L, Billings T, Wang X. Directed evolution of Zymomonas mobilis sugar facilitator Glf to overcome glucose inhibition. J Ind Microbiol Biotechnol 2021; 49:6371102. [PMID: 34529081 PMCID: PMC9118996 DOI: 10.1093/jimb/kuab066] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/22/2021] [Accepted: 09/04/2021] [Indexed: 12/01/2022]
Abstract
Cellular import of D-xylose, the second most abundant sugar in typical lignocellulosic biomass, has been evidenced to be an energy-depriving process in bacterial biocatalysts. The sugar facilitator of Zymomonas mobilis, Glf, is capable of importing xylose at high rates without extra energy input, but is inhibited by D-glucose (the primary biomass sugar), potentially limiting the utility of this transporter for fermentation of sugar mixtures derived from lignocellulose. In this work we developed an Escherichia coli platform strain deficient in glucose and xylose transport to facilitate directed evolution of Glf to overcome glucose inhibition. Using this platform, we isolated nine Glf variants created by both random and site-saturation mutagenesis with increased xylose utilization rates ranging from 4.8-fold to 13-fold relative to wild-type Glf when fermenting 100 g l–1 glucose–xylose mixtures. Diverse point mutations such as A165M and L445I were discovered leading to released glucose inhibition. Most of these mutations likely alter sugar coordinating pocket for the 6-hydroxymethyl group of D-glucose. These discovered glucose-resistant Glf variants can be potentially used as energy-conservative alternatives to the native sugar transport systems of bacterial biocatalysts for fermentation of lignocellulose-derived sugars.
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Affiliation(s)
- Gavin Kurgan
- School of Life Sciences, Arizona State University, Tempe, Arizona, USA
| | - Moses Onyeabor
- School of Life Sciences, Arizona State University, Tempe, Arizona, USA
| | - Steven C Holland
- School of Life Sciences, Arizona State University, Tempe, Arizona, USA
| | - Eric Taylor
- School of Life Sciences, Arizona State University, Tempe, Arizona, USA
| | - Aidan Schneider
- School of Life Sciences, Arizona State University, Tempe, Arizona, USA
| | - Logan Kurgan
- School of Life Sciences, Arizona State University, Tempe, Arizona, USA
| | - Tommy Billings
- School of Life Sciences, Arizona State University, Tempe, Arizona, USA
| | - Xuan Wang
- School of Life Sciences, Arizona State University, Tempe, Arizona, USA
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Wu C, Spiller R, Dowe N, Bomble YJ, St John PC. Thermodynamic and Kinetic Modeling of Co-utilization of Glucose and Xylose for 2,3-BDO Production by Zymomonas mobilis. Front Bioeng Biotechnol 2021; 9:707749. [PMID: 34381766 PMCID: PMC8350737 DOI: 10.3389/fbioe.2021.707749] [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: 05/10/2021] [Accepted: 06/30/2021] [Indexed: 11/20/2022] Open
Abstract
Prior engineering of the ethanologen Zymomonas mobilis has enabled it to metabolize xylose and to produce 2,3-butanediol (2,3-BDO) as a dominant fermentation product. When co-fermenting with xylose, glucose is preferentially utilized, even though xylose metabolism generates ATP more efficiently during 2,3-BDO production on a BDO-mol basis. To gain a deeper understanding of Z. mobilis metabolism, we first estimated the kinetic parameters of the glucose facilitator protein of Z. mobilis by fitting a kinetic uptake model, which shows that the maximum transport capacity of glucose is seven times higher than that of xylose, and glucose is six times more affinitive to the transporter than xylose. With these estimated kinetic parameters, we further compared the thermodynamic driving force and enzyme protein cost of glucose and xylose metabolism. It is found that, although 20% more ATP can be yielded stoichiometrically during xylose utilization, glucose metabolism is thermodynamically more favorable with 6% greater cumulative Gibbs free energy change, more economical with 37% less enzyme cost required at the initial stage and sustains the advantage of the thermodynamic driving force and protein cost through the fermentation process until glucose is exhausted. Glucose-6-phosphate dehydrogenase (g6pdh), glyceraldehyde-3-phosphate dehydrogenase (gapdh) and phosphoglycerate mutase (pgm) are identified as thermodynamic bottlenecks in glucose utilization pathway, as well as two more enzymes of xylose isomerase and ribulose-5-phosphate epimerase in xylose metabolism. Acetolactate synthase is found as potential engineering target for optimized protein cost supporting unit metabolic flux. Pathway analysis was then extended to the core stoichiometric matrix of Z. mobilis metabolism. Growth was simulated by dynamic flux balance analysis and the model was validated showing good agreement with experimental data. Dynamic FBA simulations suggest that a high agitation is preferable to increase 2,3-BDO productivity while a moderate agitation will benefit the 2,3-BDO titer. Taken together, this work provides thermodynamic and kinetic insights of Z. mobilis metabolism on dual substrates, and guidance of bioengineering efforts to increase hydrocarbon fuel production.
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Affiliation(s)
- Chao Wu
- Biosciences Center, National Renewable Energy Laboratory, Golden, CO, United States
| | - Ryan Spiller
- Biosciences Center, National Renewable Energy Laboratory, Golden, CO, United States
| | - Nancy Dowe
- Biosciences Center, National Renewable Energy Laboratory, Golden, CO, United States.,National Bioenergy Center, National Renewable Energy Laboratory, Golden, CO, United States
| | - Yannick J Bomble
- Biosciences Center, National Renewable Energy Laboratory, Golden, CO, United States
| | - Peter C St John
- Biosciences Center, National Renewable Energy Laboratory, Golden, CO, United States
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7
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Yi X, Lin L, Mei J, Wang W. Transporter proteins in Zymomonas mobilis contribute to the tolerance of lignocellulose-derived phenolic aldehyde inhibitors. Bioprocess Biosyst Eng 2021; 44:1875-1882. [PMID: 33839896 DOI: 10.1007/s00449-021-02567-x] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/12/2021] [Accepted: 03/31/2021] [Indexed: 01/29/2023]
Abstract
Transporter proteins are of great importance for improving the tolerance of fermentation strains to lignocellulose-derived furans and phenolic inhibitors. Different from the documented transporter proteins responsible for the tolerance of furfural and 5-hydroxymethyl-furfural (HMF), transporters responsible for that of varied phenolic aldehyde inhibitors were less investigated and elucidated. Here, an interesting phenomenon was found that no phenolic alcohols were accumulated from phenolic aldehydes degradation in Zymomonas mobilis. A transcriptional profiling of transporter genes was established in Z. mobilis ZM4 under phenolic aldehydes stress using DNA microarray. Six transporter proteins were identified as the potential candidates responsible for the tolerance of phenolic aldehydes including ABC transporter (ZMO0799 and ZMO0800), MFS transporter (ZMO1288 and ZMO1856), and RND transporter (ZMO0282 and ZMO0798). Furthermore, the analysis showed that the key transporters were significantly correlated with oxidoreductases and transcriptional regulators. This work would provide several important transporter genes serving as synthetic biology tools for improving the robustness of biorefinery strains.
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Affiliation(s)
- Xia Yi
- Jiangxi Provincial Key Laboratory of Systems Biomedicine, Jiujiang University, 17 Lufeng Road, Jiujiang, 332000, China.
| | - Ling Lin
- Jiangxi Provincial Key Laboratory of Systems Biomedicine, Jiujiang University, 17 Lufeng Road, Jiujiang, 332000, China
| | - Jun Mei
- Jiangxi Provincial Key Laboratory of Systems Biomedicine, Jiujiang University, 17 Lufeng Road, Jiujiang, 332000, China
| | - Wei Wang
- State Key Laboratory of Bioreactor Engineering, East China University of Science and Technology, 130 Meilong Road, Shanghai, 200237, China
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8
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Sarkar P, Goswami G, Mukherjee M, Das D. Heterologous expression of xylose specific transporter improves xylose utilization by recombinant Zymomonas mobilis strain in presence of glucose. Process Biochem 2021. [DOI: 10.1016/j.procbio.2021.01.006] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
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9
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Nduko JM, Taguchi S. Microbial Production of Biodegradable Lactate-Based Polymers and Oligomeric Building Blocks From Renewable and Waste Resources. Front Bioeng Biotechnol 2021; 8:618077. [PMID: 33614605 PMCID: PMC7889595 DOI: 10.3389/fbioe.2020.618077] [Citation(s) in RCA: 16] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/16/2020] [Accepted: 12/17/2020] [Indexed: 12/20/2022] Open
Abstract
Polyhydroxyalkanoates (PHAs) are naturally occurring biopolymers produced by microorganisms. PHAs have become attractive research biomaterials in the past few decades owing to their extensive potential industrial applications, especially as sustainable alternatives to the fossil fuel feedstock-derived products such as plastics. Among the biopolymers are the bioplastics and oligomers produced from the fermentation of renewable plant biomass. Bioplastics are intracellularly accumulated by microorganisms as carbon and energy reserves. The bioplastics, however, can also be produced through a biochemistry process that combines fermentative secretory production of monomers and/or oligomers and chemical synthesis to generate a repertoire of biopolymers. PHAs are particularly biodegradable and biocompatible, making them a part of today's commercial polymer industry. Their physicochemical properties that are similar to those of petrochemical-based plastics render them potential renewable plastic replacements. The design of efficient tractable processes using renewable biomass holds key to enhance their usage and adoption. In 2008, a lactate-polymerizing enzyme was developed to create new category of polyester, lactic acid (LA)-based polymer and related polymers. This review aims to introduce different strategies including metabolic and enzyme engineering to produce LA-based biopolymers and related oligomers that can act as precursors for catalytic synthesis of polylactic acid. As the cost of PHA production is prohibitive, the review emphasizes attempts to use the inexpensive plant biomass as substrates for LA-based polymer and oligomer production. Future prospects and challenges in LA-based polymer and oligomer production are also highlighted.
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Affiliation(s)
- John Masani Nduko
- Department of Dairy and Food Science and Technology, Faculty of Agriculture, Egerton University, Egerton, Kenya
| | - Seiichi Taguchi
- Department of Chemistry for Life Sciences and Agriculture, Faculty of Life Sciences and Agriculture, Tokyo University of Agriculture, Tokyo, Japan
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Fox KJ, Prather KLJ. Carbon catabolite repression relaxation in Escherichia coli: global and sugar-specific methods for glucose and secondary sugar co-utilization. Curr Opin Chem Eng 2020. [DOI: 10.1016/j.coche.2020.05.005] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
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11
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Adaptive laboratory evolution induced novel mutations in Zymomonas mobilis ATCC ZW658: a potential platform for co-utilization of glucose and xylose. ACTA ACUST UNITED AC 2020; 47:329-341. [DOI: 10.1007/s10295-020-02270-y] [Citation(s) in RCA: 20] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2019] [Accepted: 03/02/2020] [Indexed: 01/22/2023]
Abstract
Abstract
A systematic adaptive laboratory evolution strategy was employed to develop a potential Zymomonas mobilis strain with the ability to co-utilize glucose and xylose. Z. mobilis ATCC ZW658, a recombinant xylose fermenting strain, was subjected to adaptive laboratory evolution over a period of 200 days under strict selection pressure of increasing concentration of xylose. The evolved strain exhibited 1.65 times increase in the overall specific xylose utilization rate when compared with the parent strain. Furthermore, the strain displayed significantly improved performance in terms of co-fermentation of xylose in the presence of glucose with specific glucose and xylose utilization rate of 1.24 g g−1 h−1 and 1.34 g g−1 h−1, respectively. Altered phenotypic response of the evolved strain, in terms of improved xylose utilization, co-utilization of mixed sugars, enhanced growth, ethanol production, and reduced xylitol production has been explained by novel mutations, identified using next-generation sequencing, in xylose assimilating, metabolizing, and crucial regulatory pathway genes and key enzyme activity assays.
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12
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Guo Q, Mei S, Xie C, Mi H, Jiang Y, Zhang SD, Tan TW, Fan LH. Reprogramming of sugar transport pathways in Escherichia coli using a permeabilized SecY protein-translocation channel. Biotechnol Bioeng 2020; 117:1738-1746. [PMID: 32048725 PMCID: PMC7147117 DOI: 10.1002/bit.27306] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/08/2019] [Revised: 01/13/2020] [Accepted: 02/10/2020] [Indexed: 12/22/2022]
Abstract
In the initial step of sugar metabolism, sugar‐specific transporters play a decisive role in the passage of sugars through plasma membranes into cytoplasm. The SecY complex (SecYEG) in bacteria forms a membrane channel responsible for protein translocation. The present work shows that permeabilized SecY channels can be used as nonspecific sugar transporters in Escherichia coli. SecY with the plug domain deleted allowed the passage of glucose, fructose, mannose, xylose, and arabinose, and, with additional pore‐ring mutations, facilitated lactose transport, indicating that sugar passage via permeabilized SecY was independent of sugar stereospecificity. The engineered E. coli showed rapid growth on a wide spectrum of monosaccharides and benefited from the elimination of transport saturation, improvement in sugar tolerance, reduction in competitive inhibition, and prevention of carbon catabolite repression, which are usually encountered with native sugar uptake systems. The SecY channel is widespread in prokaryotes, so other bacteria may also be engineered to utilize this system for sugar uptake. The SecY channel thus provides a unique sugar passageway for future development of robust cell factories for biotechnological applications.
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Affiliation(s)
- Qiang Guo
- Beijing Key Laboratory of Bioprocess, College of Life Science and Technology, Beijing University of Chemical Technology, Beijing, China
| | - Sen Mei
- Beijing Key Laboratory of Bioprocess, College of Life Science and Technology, Beijing University of Chemical Technology, Beijing, China
| | - Chong Xie
- Beijing Key Laboratory of Bioprocess, College of Life Science and Technology, Beijing University of Chemical Technology, Beijing, China
| | - Hao Mi
- Beijing Key Laboratory of Bioprocess, College of Life Science and Technology, Beijing University of Chemical Technology, Beijing, China
| | - Yang Jiang
- Beijing Key Laboratory of Bioprocess, College of Life Science and Technology, Beijing University of Chemical Technology, Beijing, China
| | - Shi-Ding Zhang
- Beijing Key Laboratory of Bioprocess, College of Life Science and Technology, Beijing University of Chemical Technology, Beijing, China
| | - Tian-Wei Tan
- Beijing Key Laboratory of Bioprocess, College of Life Science and Technology, Beijing University of Chemical Technology, Beijing, China
| | - Li-Hai Fan
- Beijing Key Laboratory of Bioprocess, College of Life Science and Technology, Beijing University of Chemical Technology, Beijing, China
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Zhang Z, Lin L, Tang H, Zeng S, Guo Y, Wei Y, Huang R, Pang H, Du L. A Convenient Fluorescence-Based Assay for the Detection of Sucrose Transport and the Introduction of a Sucrose Transporter from Potato into Clostridium Strains. Molecules 2019; 24:molecules24193495. [PMID: 31561523 PMCID: PMC6803915 DOI: 10.3390/molecules24193495] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/24/2019] [Revised: 09/23/2019] [Accepted: 09/24/2019] [Indexed: 11/16/2022] Open
Abstract
A convenient and effective sucrose transport assay for Clostridium strains is needed. Traditional methods, such as 14C-sucrose isotope labelling, use radioactive materials and are not convenient for many laboratories. Here, a sucrose transporter from potato was introduced into Clostridium, and a fluorescence assay based on esculin was used for the analysis of sucrose transport in Clostridium strains. This showed that the heterologously expressed potato sucrose transporter is functional in Clostridium. Recombinant engineering of high-level sucrose transport would aid sucrose fermentation in Clostridium strains. The assay described herein provides an important technological platform for studying sucrose transporter function following heterologous expression in Clostridium.
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Affiliation(s)
- Zhikai Zhang
- State Key Laboratory for Conservation and Utilization of Subtropical Agro-bioresources, Guangxi Research Center for Microbial and Enzymatic Technology, College of Life Science and Technology, Guangxi University, Daxue Road No. 100, Nanning 530005, China.
| | - Lihua Lin
- National Engineering Research Center for Non-Food Biorefinery, State Key Laboratory of Non-Food Biomass and Enzyme Technology, Guangxi Key Laboratory of Bio-refinery, Guangxi Academy of Sciences, Daling Road No. 98, Nanning 530007, China.
| | - Hongchi Tang
- National Engineering Research Center for Non-Food Biorefinery, State Key Laboratory of Non-Food Biomass and Enzyme Technology, Guangxi Key Laboratory of Bio-refinery, Guangxi Academy of Sciences, Daling Road No. 98, Nanning 530007, China.
| | - Shaowei Zeng
- State Key Laboratory for Conservation and Utilization of Subtropical Agro-bioresources, Guangxi Research Center for Microbial and Enzymatic Technology, College of Life Science and Technology, Guangxi University, Daxue Road No. 100, Nanning 530005, China.
| | - Yuan Guo
- National Engineering Research Center for Non-Food Biorefinery, State Key Laboratory of Non-Food Biomass and Enzyme Technology, Guangxi Key Laboratory of Bio-refinery, Guangxi Academy of Sciences, Daling Road No. 98, Nanning 530007, China.
| | - Yutuo Wei
- State Key Laboratory for Conservation and Utilization of Subtropical Agro-bioresources, Guangxi Research Center for Microbial and Enzymatic Technology, College of Life Science and Technology, Guangxi University, Daxue Road No. 100, Nanning 530005, China.
| | - Ribo Huang
- State Key Laboratory for Conservation and Utilization of Subtropical Agro-bioresources, Guangxi Research Center for Microbial and Enzymatic Technology, College of Life Science and Technology, Guangxi University, Daxue Road No. 100, Nanning 530005, China.
| | - Hao Pang
- National Engineering Research Center for Non-Food Biorefinery, State Key Laboratory of Non-Food Biomass and Enzyme Technology, Guangxi Key Laboratory of Bio-refinery, Guangxi Academy of Sciences, Daling Road No. 98, Nanning 530007, China.
| | - Liqin Du
- State Key Laboratory for Conservation and Utilization of Subtropical Agro-bioresources, Guangxi Research Center for Microbial and Enzymatic Technology, College of Life Science and Technology, Guangxi University, Daxue Road No. 100, Nanning 530005, China.
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14
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Engineering xylose metabolism for production of polyhydroxybutyrate in the non-model bacterium Burkholderia sacchari. Microb Cell Fact 2018; 17:74. [PMID: 29764418 PMCID: PMC5952831 DOI: 10.1186/s12934-018-0924-9] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/21/2018] [Accepted: 05/05/2018] [Indexed: 12/22/2022] Open
Abstract
Background Despite its ability to grow and produce high-value molecules using renewable carbon sources, two main factors must be improved to use Burkholderia sacchari as a chassis for bioproduction at an industrial scale: first, the lack of molecular tools to engineer this organism and second, the inherently slow growth rate and poly-3-hydroxybutyrate [P(3HB)] production using xylose. In this work, we have addressed both factors. Results First, we adapted a set of BglBrick plasmids and showed tunable expression in B. sacchari. Finally, we assessed growth rate and P(3HB) production through overexpression of xylose transporters, catabolic or regulatory genes. Overexpression of xylR significantly improved growth rate (55.5% improvement), polymer yield (77.27% improvement), and resulted in 71% of cell dry weight as P(3HB). Conclusions These values are unprecedented for P(3HB) accumulation using xylose as a sole carbon source and highlight the importance of precise expression control for improving utilization of hemicellulosic sugars in B. sacchari.![]()
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Improved Xylose Metabolism by a CYC8 Mutant of Saccharomyces cerevisiae. Appl Environ Microbiol 2017; 83:AEM.00095-17. [PMID: 28363963 DOI: 10.1128/aem.00095-17] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/11/2017] [Accepted: 03/24/2017] [Indexed: 11/20/2022] Open
Abstract
Engineering Saccharomyces cerevisiae for the utilization of pentose sugars is an important goal for the production of second-generation bioethanol and biochemicals. However, S. cerevisiae lacks specific pentose transporters, and in the presence of glucose, pentoses enter the cell inefficiently via endogenous hexose transporters (HXTs). By means of in vivo engineering, we have developed a quadruple hexokinase deletion mutant of S. cerevisiae that evolved into a strain that efficiently utilizes d-xylose in the presence of high d-glucose concentrations. A genome sequence analysis revealed a mutation (Y353C) in the general corepressor CYC8, or SSN6, which was found to be responsible for the phenotype when introduced individually in the nonevolved strain. A transcriptome analysis revealed altered expression of 95 genes in total, including genes involved in (i) hexose transport, (ii) maltose metabolism, (iii) cell wall function (mannoprotein family), and (iv) unknown functions (seripauperin multigene family). Of the 18 known HXTs, genes for 9 were upregulated, especially the low or nonexpressed HXT10, HXT13, HXT15, and HXT16 Mutant cells showed increased uptake rates of d-xylose in the presence of d-glucose, as well as elevated maximum rates of metabolism (Vmax) for both d-glucose and d-xylose transport. The data suggest that the increased expression of multiple hexose transporters renders d-xylose metabolism less sensitive to d-glucose inhibition due to an elevated transport rate of d-xylose into the cell.IMPORTANCE The yeast Saccharomyces cerevisiae is used for second-generation bioethanol formation. However, growth on xylose is limited by pentose transport through the endogenous hexose transporters (HXTs), as uptake is outcompeted by the preferred substrate, glucose. Mutant strains were obtained with improved growth characteristics on xylose in the presence of glucose, and the mutations mapped to the regulator Cyc8. The inactivation of Cyc8 caused increased expression of HXTs, thereby providing more capacity for the transport of xylose, presenting a further step toward a more robust process of industrial fermentation of lignocellulosic biomass using yeast.
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Jo S, Yoon J, Lee SM, Um Y, Han SO, Woo HM. Modular pathway engineering of Corynebacterium glutamicum to improve xylose utilization and succinate production. J Biotechnol 2017; 258:69-78. [PMID: 28153765 DOI: 10.1016/j.jbiotec.2017.01.015] [Citation(s) in RCA: 43] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/06/2016] [Revised: 01/24/2017] [Accepted: 01/27/2017] [Indexed: 11/26/2022]
Abstract
Xylose-negative Corynebacterium glutamicum has been engineered to utilize xylose as the sole carbon source via either the xylose isomerase (XI) pathway or the Weimberg pathway. Heterologous expression of xylose isomerase and overexpression of a gene encoding for xylulose kinase enabled efficient xylose utilization. In this study, we show that two functionally-redundant transcriptional regulators (GntR1 and GntR2) present on xylose repress the pentose phosphate pathway genes. For efficient xylose utilization, pentose phosphate pathway genes and a phosphoketolase gene were overexpressed with the XI pathway in C. glutamicum. Overexpression of the genes encoding for transaldolase (Tal), 6-phosphogluconate dehydrogenase (Gnd), or phosphoketolase (XpkA) enhanced the growth and xylose consumption rates compared to the wild-type with the XI pathway alone. However, co-expression of these genes did not have a synergetic effect on xylose utilization. For the succinate production from xylose, overexpression of the tal gene with the XI pathway in a succinate-producing strain improved xylose utilization and increased the specific succinate production rate by 2.5-fold compared to wild-type with the XI pathway alone. Thus, overexpression of the tal, gnd, or xpkA gene could be helpful for engineering C. glutamicum toward production of value-added chemicals with efficient xylose utilization.
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Affiliation(s)
- Suah Jo
- Clean Energy Research Center, Korea Institute of Science and Technology, Hwarang-ro 14-gil 5, Seongbuk-gu, Seoul 02792, Republic of Korea; Department of Biotechnology, Korea University, 145 Anam-ro, Seongbuk-gu, Seoul 02841, Republic of Korea
| | - Jinkyung Yoon
- Department of Food Science and Biotechnology, Sungkyunkwan University (SKKU), 2066 Seobu-ro, Jangan-gu, Suwon 16419, Republic of Korea
| | - Sun-Mi Lee
- Clean Energy Research Center, Korea Institute of Science and Technology, Hwarang-ro 14-gil 5, Seongbuk-gu, Seoul 02792, Republic of Korea
| | - Youngsoon Um
- Clean Energy Research Center, Korea Institute of Science and Technology, Hwarang-ro 14-gil 5, Seongbuk-gu, Seoul 02792, Republic of Korea
| | - Sung Ok Han
- Department of Biotechnology, Korea University, 145 Anam-ro, Seongbuk-gu, Seoul 02841, Republic of Korea
| | - Han Min Woo
- Department of Food Science and Biotechnology, Sungkyunkwan University (SKKU), 2066 Seobu-ro, Jangan-gu, Suwon 16419, Republic of Korea.
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Groot J, Cepress-Mclean SC, Robbins-Pianka A, Knight R, Gill RT. Multiplex growth rate phenotyping of synthetic mutants in selection to engineer glucose and xylose co-utilization in Escherichia coli. Biotechnol Bioeng 2016; 114:885-893. [PMID: 27861733 DOI: 10.1002/bit.26217] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/28/2016] [Revised: 11/02/2016] [Accepted: 11/06/2016] [Indexed: 12/25/2022]
Abstract
Engineering the simultaneous consumption of glucose and xylose sugars is critical to enable the sustainable production of biofuels from lignocellulosic biomass. In most major industrial microorganisms glucose completely inhibits the uptake of xylose, limiting efficient sugar mixture conversion. In E. coli removal of the major glucose transporter PTS allows for glucose and xylose co-consumption but only after prolonged adaptation, which is an effective process but hard to control and prone to co-evolving undesired traits. Here we synthetically engineer mutants to target sugar co-consumption properties; we subject a PTS- mutant to a short adaptive step and subsequently either delete or overexpress key genes previously suggested to affect sugar consumption. Screening the co-consumption properties of these mutants individually is very laborious. We show we can evaluate sugar co-consumption properties in parallel by culturing the mutants in selection and applying a novel approach that computes mutant growth rates in selection using chromosomal barcode counts obtained from Next-Generation Sequencing. We validate this multiplex growth rate phenotyping approach with individual mutant pure cultures, identify new instances of mutants cross-feeding on metabolic byproducts, and, importantly, find that the rates of glucose and xylose co-consumption can be tuned by altering glucokinase expression in our PTS- background. Biotechnol. Bioeng. 2017;114: 885-893. © 2016 Wiley Periodicals, Inc.
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Affiliation(s)
- Joost Groot
- Department of Chemical and Biological Engineering, University of Colorado, Boulder, Colorado
| | - Sidney C Cepress-Mclean
- Department of Chemical and Biological Engineering, University of Colorado, Boulder, Colorado
| | | | - Rob Knight
- Biofrontiers Institute, University of Colorado, Boulder, Colorado
| | - Ryan T Gill
- Department of Chemical and Biological Engineering, University of Colorado, Boulder, Colorado
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Ranade S, Zhang Y, Kaplan M, Majeed W, He Q. Metabolic Engineering and Comparative Performance Studies of Synechocystis sp. PCC 6803 Strains for Effective Utilization of Xylose. Front Microbiol 2015; 6:1484. [PMID: 26732758 PMCID: PMC4689873 DOI: 10.3389/fmicb.2015.01484] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/10/2015] [Accepted: 12/09/2015] [Indexed: 01/16/2023] Open
Abstract
Wood sugars such as xylose can be used as an inexpensive carbon source for biotechnological applications. The model cyanobacterium Synechocystis sp. PCC 6803 lacks the ability to catabolize wood sugars as an energy source. Here, we generated four Synechocystis strains that heterologously expressed XylAB enzymes, which mediate xylose catabolism, either in combination with or without one of three xylose transporters, namely XylE, GalP, or Glf. Except for glf, which is derived from the bacterium Zymomonas mobilis ZM4, the heterologous genes were sourced from Escherichia coli K-12. All of the recombinant strains were able to utilize xylose in the absence of catabolite repression. When xylose was the lone source of organic carbon, strains possessing the XylE and Glf transporters were most efficient in terms of dry biomass production and xylose consumption and the strain lacking a heterologous transporter was the least efficient. However, in the presence of a xylose-glucose mixed sugar source, the strains exhibited similar levels of growth and xylose consumption. This study demonstrates that various bacterial xylose transporters can boost xylose catabolism in transgenic Synechocystis strains, and paves the way for the sustainable production of bio-compounds and green fuels from lignocellulosic biomass.
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Affiliation(s)
- Saurabh Ranade
- Department of Biology, University of Arkansas at Little Rock Little Rock, AR, USA
| | - Yan Zhang
- Biotechnology Research Center, Shandong Academy of Agricultural Sciences Jinan, China
| | - Mecit Kaplan
- Department of Biology, University of Arkansas at Little Rock Little Rock, AR, USA
| | - Waqar Majeed
- Center for Integrative Nanotechnology Sciences, University of Arkansas at Little Rock Little Rock, AR, USA
| | - Qingfang He
- Department of Biology, University of Arkansas at Little Rock Little Rock, AR, USA
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Dunn KL, Rao CV. High-throughput sequencing reveals adaptation-induced mutations in pentose-fermenting strains ofZymomonas mobilis. Biotechnol Bioeng 2015; 112:2228-40. [DOI: 10.1002/bit.25631] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/15/2015] [Revised: 03/22/2015] [Accepted: 04/29/2015] [Indexed: 11/09/2022]
Affiliation(s)
- Kori L. Dunn
- Department of Chemical and Biomolecular Engineering; University of Illinois at Urbana-Champaign; Urbana Illinois 61801
| | - Christopher V. Rao
- Department of Chemical and Biomolecular Engineering; University of Illinois at Urbana-Champaign; Urbana Illinois 61801
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Shin HY, Nijland JG, de Waal PP, de Jong RM, Klaassen P, Driessen AJM. An engineered cryptic Hxt11 sugar transporter facilitates glucose-xylose co-consumption in Saccharomyces cerevisiae. BIOTECHNOLOGY FOR BIOFUELS 2015; 8:176. [PMID: 26535057 PMCID: PMC4630928 DOI: 10.1186/s13068-015-0360-6] [Citation(s) in RCA: 48] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/14/2015] [Accepted: 10/22/2015] [Indexed: 05/15/2023]
Abstract
BACKGROUND The yeast Saccharomyces cerevisiae is unable to ferment pentose sugars like d-xylose. Through the introduction of the respective metabolic pathway, S. cerevisiae is able to ferment xylose but first utilizes d-glucose before the d-xylose can be transported and metabolized. Low affinity d-xylose uptake occurs through the endogenous hexose (Hxt) transporters. For a more robust sugar fermentation, co-consumption of d-glucose and d-xylose is desired as d-xylose fermentation is in particular prone to inhibition by compounds present in pretreated lignocellulosic feedstocks. RESULTS Evolutionary engineering of a d-xylose-fermenting S. cerevisiae strain lacking the major transporter HXT1-7 and GAL2 genes yielded a derivative that shows improved growth on xylose because of the expression of a normally cryptic HXT11 gene. Hxt11 also supported improved growth on d-xylose by the wild-type strain. Further selection for glucose-insensitive growth on d-xylose employing a quadruple hexokinase deletion yielded mutations at N366 of Hxt11 that reversed the transporter specificity for d-glucose into d-xylose while maintaining high d-xylose transport rates. The Hxt11 mutant enabled the efficient co-fermentation of xylose and glucose at industrially relevant sugar concentrations when expressed in a strain lacking the HXT1-7 and GAL2 genes. CONCLUSIONS Hxt11 is a cryptic sugar transporter of S. cerevisiae that previously has not been associated with effective d-xylose transport. Mutagenesis of Hxt11 yielded transporters that show a better affinity for d-xylose as compared to d-glucose while maintaining high transport rates. d-glucose and d-xylose co-consumption is due to a redistribution of the sugar transport flux while maintaining the total sugar conversion rate into ethanol. This method provides a single transporter solution for effective fermentation on lignocellulosic feedstocks.
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Affiliation(s)
- Hyun Yong Shin
- />Molecular Microbiology, Groningen Biomolecular Sciences and Biotechnology, University of Groningen, Zernike Institute for Advanced Materials and Kluyver Centre for Genomics of Industrial Fermentation, Nijenborgh 7, 9747 AG Groningen, The Netherlands
| | - Jeroen G. Nijland
- />Molecular Microbiology, Groningen Biomolecular Sciences and Biotechnology, University of Groningen, Zernike Institute for Advanced Materials and Kluyver Centre for Genomics of Industrial Fermentation, Nijenborgh 7, 9747 AG Groningen, The Netherlands
| | - Paul P. de Waal
- />DSM Biotechnology Center, Alexander Fleminglaan 1, 2613 AX Delft, The Netherlands
| | - René M. de Jong
- />DSM Biotechnology Center, Alexander Fleminglaan 1, 2613 AX Delft, The Netherlands
| | - Paul Klaassen
- />DSM Biotechnology Center, Alexander Fleminglaan 1, 2613 AX Delft, The Netherlands
| | - Arnold J. M. Driessen
- />Molecular Microbiology, Groningen Biomolecular Sciences and Biotechnology, University of Groningen, Zernike Institute for Advanced Materials and Kluyver Centre for Genomics of Industrial Fermentation, Nijenborgh 7, 9747 AG Groningen, The Netherlands
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Directed evolution of a cellodextrin transporter for improved biofuel production under anaerobic conditions inSaccharomyces cerevisiae. Biotechnol Bioeng 2014; 111:1521-31. [DOI: 10.1002/bit.25214] [Citation(s) in RCA: 36] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/13/2013] [Revised: 01/06/2014] [Accepted: 02/03/2014] [Indexed: 12/12/2022]
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Nijland JG, Shin HY, de Jong RM, de Waal PP, Klaassen P, Driessen AJM. Engineering of an endogenous hexose transporter into a specific D-xylose transporter facilitates glucose-xylose co-consumption in Saccharomyces cerevisiae. BIOTECHNOLOGY FOR BIOFUELS 2014; 7:168. [PMID: 25505932 PMCID: PMC4263072 DOI: 10.1186/s13068-014-0168-9] [Citation(s) in RCA: 85] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/17/2014] [Accepted: 11/13/2014] [Indexed: 05/12/2023]
Abstract
BACKGROUND Engineering of Saccharomyces cerevisiae for the simultaneous utilization of hexose and pentose sugars is vital for cost-efficient cellulosic bioethanol production. This yeast lacks specific pentose transporters and depends on endogenous hexose transporters for low affinity pentose uptake. Consequently, engineered xylose-fermenting yeast strains first utilize D-glucose before D-xylose can be transported and metabolized. RESULTS We have used an evolutionary engineering approach that depends on a quadruple hexokinase deletion xylose-fermenting S. cerevisiae strain to select for growth on D-xylose in the presence of high D-glucose concentrations. This resulted in D-glucose-tolerant growth of the yeast of D-xylose. This could be attributed to mutations at N367 in the endogenous chimeric Hxt36 transporter, causing a defect in D-glucose transport while still allowing specific uptake of D-xylose. The Hxt36-N367A variant transports D-xylose with a high rate and improved affinity, enabling the efficient co-consumption of D-glucose and D-xylose. CONCLUSIONS Engineering of yeast endogenous hexose transporters provides an effective strategy to construct glucose-insensitive xylose transporters that are well integrated in the carbon metabolism regulatory network, and that can be used for efficient lignocellulosic bioethanol production.
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Affiliation(s)
- Jeroen G Nijland
- />Molecular Microbiology, Groningen Biomolecular Sciences and Biotechnology, University of Groningen, Zernike Institute for Advanced Materials and Kluyver Centre for Genomics of Industrial Fermentation, Groningen, The Netherlands
| | - Hyun Yong Shin
- />Molecular Microbiology, Groningen Biomolecular Sciences and Biotechnology, University of Groningen, Zernike Institute for Advanced Materials and Kluyver Centre for Genomics of Industrial Fermentation, Groningen, The Netherlands
| | - René M de Jong
- />DSM Biotechnology Center, Alexander Fleminglaan 1, 2613 AX Delft, The Netherlands
| | - Paul P de Waal
- />DSM Biotechnology Center, Alexander Fleminglaan 1, 2613 AX Delft, The Netherlands
| | - Paul Klaassen
- />DSM Biotechnology Center, Alexander Fleminglaan 1, 2613 AX Delft, The Netherlands
| | - Arnold JM Driessen
- />Molecular Microbiology, Groningen Biomolecular Sciences and Biotechnology, University of Groningen, Zernike Institute for Advanced Materials and Kluyver Centre for Genomics of Industrial Fermentation, Groningen, The Netherlands
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Yang S, Franden MA, Brown SD, Chou YC, Pienkos PT, Zhang M. Insights into acetate toxicity in Zymomonas mobilis 8b using different substrates. BIOTECHNOLOGY FOR BIOFUELS 2014; 7:140. [PMID: 25298783 PMCID: PMC4189746 DOI: 10.1186/s13068-014-0140-8] [Citation(s) in RCA: 33] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/13/2014] [Accepted: 09/11/2014] [Indexed: 05/19/2023]
Abstract
BACKGROUND Lignocellulosic biomass is a promising renewable feedstock for biofuel production. Acetate is one of the major inhibitors liberated from hemicelluloses during hydrolysis. An understanding of the toxic effects of acetate on the fermentation microorganism and the efficient utilization of mixed sugars of glucose and xylose in the presence of hydrolysate inhibitors is crucial for economic biofuel production. RESULTS A new microarray was designed including both coding sequences and intergenic regions to investigate the acetate stress responses of Zymomonas mobilis 8b when using single carbon sources of glucose or xylose, or mixed sugars of both glucose and xylose. With the supplementation of exogenous acetate, 8b can utilize all the glucose with a similar ethanol yield, although the growth, final biomass, and ethanol production rate were reduced. However, xylose utilization was inhibited in both media containing xylose or a mixed sugar of glucose and xylose, although the performance of 8b was better in mixed sugar than xylose-only media. The presence of acetate caused genes related to biosynthesis, the flagellar system, and glycolysis to be downregulated, and genes related to stress responses and energy metabolism to be upregulated. Unexpectedly, xylose seems to pose more stress on 8b, recruiting more genes for xylose utilization, than does acetate. Several gene candidates based on transcriptome results were selected for genetic manipulation, and a TonB-dependent receptor knockout mutant was confirmed to have a slight advantage regarding acetate tolerance. CONCLUSIONS Our results indicate Z. mobilis utilized a different mechanism for xylose utilization, with an even more severe impact on Z. mobilis than that caused by acetate treatment. Our study also suggests redox imbalance caused by stressful conditions may trigger a metabolic reaction leading to the accumulation of toxic intermediates such as xylitol, but Z. mobilis manages its carbon and energy metabolism through the control of individual reactions to mitigate the stressful conditions. We have thus provided extensive transcriptomic datasets and gained insights into the molecular responses of Z. mobilis to the inhibitor acetate when grown in different sugar sources, which will facilitate future metabolic modeling studies and strain improvement efforts for better xylose utilization and acetate tolerance.
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Affiliation(s)
- Shihui Yang
- />National Bioenergy Center, National Renewable Energy Laboratory, Golden, CO 80401 USA
| | - Mary Ann Franden
- />National Bioenergy Center, National Renewable Energy Laboratory, Golden, CO 80401 USA
| | - Steven D Brown
- />Biosciences Division, Oak Ridge, TN 37831 USA
- />BioEnergy Science Center, Oak Ridge National Laboratory, Oak Ridge, TN 37831 USA
| | - Yat-Chen Chou
- />National Bioenergy Center, National Renewable Energy Laboratory, Golden, CO 80401 USA
| | - Philip T Pienkos
- />National Bioenergy Center, National Renewable Energy Laboratory, Golden, CO 80401 USA
| | - Min Zhang
- />National Bioenergy Center, National Renewable Energy Laboratory, Golden, CO 80401 USA
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Change, exchange, and rearrange: protein engineering for the biotechnological production of fuels, pharmaceuticals, and other chemicals. Curr Opin Biotechnol 2013; 24:1010-6. [DOI: 10.1016/j.copbio.2013.02.027] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/14/2012] [Revised: 02/25/2013] [Accepted: 02/26/2013] [Indexed: 01/07/2023]
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Yuzbashev TV, Vybornaya TV, Larina AS, Gvilava IT, Voyushina NE, Mokrova SS, Yuzbasheva EY, Manukhov IV, Sineoky SP, Debabov VG. Directed modification of Escherichia coli metabolism for the design of threonine-producing strains. APPL BIOCHEM MICRO+ 2013. [DOI: 10.1134/s0003683813090056] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
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An assay for functional xylose transporters in Saccharomyces cerevisiae. Anal Biochem 2013; 442:241-8. [DOI: 10.1016/j.ab.2013.07.041] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/20/2013] [Revised: 07/27/2013] [Accepted: 07/29/2013] [Indexed: 11/18/2022]
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Kurosawa K, Wewetzer SJ, Sinskey AJ. Engineering xylose metabolism in triacylglycerol-producing Rhodococcus opacus for lignocellulosic fuel production. BIOTECHNOLOGY FOR BIOFUELS 2013; 6:134. [PMID: 24041310 PMCID: PMC3848844 DOI: 10.1186/1754-6834-6-134] [Citation(s) in RCA: 58] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/06/2013] [Accepted: 08/27/2013] [Indexed: 05/04/2023]
Abstract
BACKGROUND There has been a great deal of interest in fuel productions from lignocellulosic biomass to minimize the conflict between food and fuel use. The bioconversion of xylose, which is the second most abundant sugar present after glucose in lignocellulosic biomass, is important for the development of cost effective bioprocesses to fuels. Rhodococcus opacus PD630, an oleaginous bacterium, accumulates large amounts of triacylglycerols (TAGs), which can be processed into advanced liquid fuels. However, R. opacus PD630 does not metabolize xylose. RESULTS We generated DNA libraries from a Streptomyces bacterium capable of utilizing xylose and introduced them into R. opacus PD630. Xsp8, one of the engineered strains, was capable of growing on up to 180 g L-1 of xylose. Xsp8 grown in batch-cultures derived from unbleached kraft hardwood pulp hydrolysate containing 70 g L-1 total sugars was able to completely and simultaneously utilize xylose and glucose present in the lignocellulosic feedstock, and yielded 11.0 g L-1 of TAGs as fatty acids, corresponding to 45.8% of the cell dry weight. The yield of total fatty acids per gram of sugars consumed was 0.178 g, which consisted primarily of palmitic acid and oleic acid. The engineered strain Xsp8 was introduced with two heterologous genes from Streptomyces: xylA, encoding xylose isomerase, and xylB, encoding xylulokinase. We further demonstrated that in addition to the introduction and the concomitant expression of heterologous xylA and xylB genes, there is another molecular target in the R. opacus genome which fully enables the functionality of xylA and xylB genes to generate the robust xylose-fermenting strain capable of efficiently producing TAGs at high xylose concentrations. CONCLUSION We successfully engineered a R. opacus strain that is capable of completely utilizing high concentrations of xylose or mixed xylose/glucose simultaneously, and substantiated its suitability for TAG production. This study demonstrates that the engineered strain possesses a key trait of converters for lipid-based fuels production from lignocellulosic biomass.
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Affiliation(s)
- Kazuhiko Kurosawa
- Department of Biology, Massachusetts Institute of Technology, 77 Massachusetts Avenue, Cambridge, MA 02139, USA
| | - Sandra J Wewetzer
- Department of Biology, Massachusetts Institute of Technology, 77 Massachusetts Avenue, Cambridge, MA 02139, USA
- Present address: Department of Biochemical Engineering, RWTH Aachen University, Worringerweg 1, 52074, Aachen, Germany
| | - Anthony J Sinskey
- Department of Biology, Massachusetts Institute of Technology, 77 Massachusetts Avenue, Cambridge, MA 02139, USA
- Engineering Systems Division, Massachusetts Institute of Technology, 77 Massachusetts Avenue, Cambridge, MA 02139, USA
- Health Sciences Technology Division, Massachusetts Institute of Technology, 77 Massachusetts Avenue, Cambridge, MA 02139, USA
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Chiang CJ, Lee HM, Guo HJ, Wang ZW, Lin LJ, Chao YP. Systematic approach to engineer Escherichia coli pathways for co-utilization of a glucose-xylose mixture. JOURNAL OF AGRICULTURAL AND FOOD CHEMISTRY 2013; 61:7583-90. [PMID: 23848609 DOI: 10.1021/jf401230r] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/16/2023]
Abstract
Glucose and xylose are two major sugars of lignocellulosic hydrolysate. The regulatory program of catabolite repression in Escherichia coli dictates the preferred utilization of glucose over xylose, which handicaps the development of the lignocellulose-based fermentation process. To co-utilize a glucose-xylose mixture, the E. coli strain was manipulated by pathway engineering in a systematic way. The approach included (1) blocking catabolite repression, (2) enhancing glucose transport, (3) increasing the activity of the pentose phosphate pathway, and (4) eliminating undesirable pathways. Moreover, the ethanol synthetic pathway from Zymomonas mobilis was introduced into the engineered strain. As a consequence, the resulting strain was able to simultaneously metabolize glucose and xylose and consume all sugars (30 g/L each) in 16 h, leading to 97% of the theoretical ethanol yield. Overall, this indicates that this approach is effective and straightforward to engineer E. coli for the desired trait.
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Affiliation(s)
- Chung-Jen Chiang
- Department of Medical Laboratory Science and Biotechnology, China Medical University , Taichung, Taiwan 40402
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Abatemarco J, Hill A, Alper HS. Expanding the metabolic engineering toolbox with directed evolution. Biotechnol J 2013; 8:1397-410. [PMID: 23857895 DOI: 10.1002/biot.201300021] [Citation(s) in RCA: 36] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/25/2013] [Revised: 06/10/2013] [Accepted: 06/24/2013] [Indexed: 01/02/2023]
Abstract
Cellular systems can be engineered into factories that produce high-value chemicals from renewable feedstock. Such an approach requires an expanded toolbox for metabolic engineering. Recently, protein engineering and directed evolution strategies have started to play a growing and critical role within metabolic engineering. This review focuses on the various ways in which directed evolution can be applied in conjunction with metabolic engineering to improve product yields. Specifically, we discuss the application of directed evolution on both catalytic and non-catalytic traits of enzymes, on regulatory elements, and on whole genomes in a metabolic engineering context. We demonstrate how the goals of metabolic pathway engineering can be achieved in part through evolving cellular parts as opposed to traditional approaches that rely on gene overexpression and deletion. Finally, we discuss the current limitations in screening technology that hinder the full implementation of a metabolic pathway-directed evolution approach.
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Affiliation(s)
- Joseph Abatemarco
- Department of Chemical Engineering, The University of Texas at Austin, Austin, TX, USA
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Eriksen DT, Hsieh PCH, Lynn P, Zhao H. Directed evolution of a cellobiose utilization pathway in Saccharomyces cerevisiae by simultaneously engineering multiple proteins. Microb Cell Fact 2013; 12:61. [PMID: 23802545 PMCID: PMC3702475 DOI: 10.1186/1475-2859-12-61] [Citation(s) in RCA: 47] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/27/2013] [Accepted: 06/03/2013] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND The optimization of metabolic pathways is critical for efficient and economical production of biofuels and specialty chemicals. One such significant pathway is the cellobiose utilization pathway, identified as a promising route in biomass utilization. Here we describe the optimization of cellobiose consumption and ethanol productivity by simultaneously engineering both proteins of the pathway, the β-glucosidase (gh1-1) and the cellodextrin transporter (cdt-1), in an example of pathway engineering through directed evolution. RESULTS The improved pathway was assessed based on the strain specific growth rate on cellobiose, with the final mutant exhibiting a 47% increase over the wild-type pathway. Metabolite analysis of the engineered pathway identified a 49% increase in cellobiose consumption (1.78 to 2.65 g cellobiose/(L · h)) and a 64% increase in ethanol productivity (0.611 to 1.00 g ethanol/(L · h)). CONCLUSIONS By simultaneously engineering multiple proteins in the pathway, cellobiose utilization in S. cerevisiae was improved. This optimization can be generally applied to other metabolic pathways, provided a selection/screening method is available for the desired phenotype. The improved in vivo cellobiose utilization demonstrated here could help to decrease the in vitro enzyme load in biomass pretreatment, ultimately contributing to a reduction in the high cost of biofuel production.
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Heselpoth RD, Nelson DC. A new screening method for the directed evolution of thermostable bacteriolytic enzymes. J Vis Exp 2012:4216. [PMID: 23169108 PMCID: PMC3520584 DOI: 10.3791/4216] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/02/2022] Open
Abstract
Directed evolution is defined as a method to harness natural selection in order to engineer proteins to acquire particular properties that are not associated with the protein in nature. Literature has provided numerous examples regarding the implementation of directed evolution to successfully alter molecular specificity and catalysis(1). The primary advantage of utilizing directed evolution instead of more rational-based approaches for molecular engineering relates to the volume and diversity of variants that can be screened(2). One possible application of directed evolution involves improving structural stability of bacteriolytic enzymes, such as endolysins. Bacteriophage encode and express endolysins to hydrolyze a critical covalent bond in the peptidoglycan (i.e. cell wall) of bacteria, resulting in host cell lysis and liberation of progeny virions. Notably, these enzymes possess the ability to extrinsically induce lysis to susceptible bacteria in the absence of phage and furthermore have been validated both in vitro and in vivo for their therapeutic potential(3-5). The subject of our directed evolution study involves the PlyC endolysin, which is composed of PlyCA and PlyCB subunits(6). When purified and added extrinsically, the PlyC holoenzyme lyses group A streptococci (GAS) as well as other streptococcal groups in a matter of seconds and furthermore has been validated in vivo against GAS(7). Significantly, monitoring residual enzyme kinetics after elevated temperature incubation provides distinct evidence that PlyC loses lytic activity abruptly at 45 °C, suggesting a short therapeutic shelf life, which may limit additional development of this enzyme. Further studies reveal the lack of thermal stability is only observed for the PlyCA subunit, whereas the PlyCB subunit is stable up to ~90 °C (unpublished observation). In addition to PlyC, there are several examples in literature that describe the thermolabile nature of endolysins. For example, the Staphylococcus aureus endolysin LysK and Streptococcus pneumoniae endolysins Cpl-1 and Pal lose activity spontaneously at 42 °C, 43.5 °C and 50.2 °C, respectively(8-10). According to the Arrhenius equation, which relates the rate of a chemical reaction to the temperature present in the particular system, an increase in thermostability will correlate with an increase in shelf life expectancy(11). Toward this end, directed evolution has been shown to be a useful tool for altering the thermal activity of various molecules in nature, but never has this particular technology been exploited successfully for the study of bacteriolytic enzymes. Likewise, successful accounts of progressing the structural stability of this particular class of antimicrobials altogether are nonexistent. In this video, we employ a novel methodology that uses an error-prone DNA polymerase followed by an optimized screening process using a 96 well microtiter plate format to identify mutations to the PlyCA subunit of the PlyC streptococcal endolysin that correlate to an increase in enzyme kinetic stability (Figure 1). Results after just one round of random mutagenesis suggest the methodology is generating PlyC variants that retain more than twice the residual activity when compared to wild-type (WT) PlyC after elevated temperature treatment.
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Affiliation(s)
- Ryan D Heselpoth
- Institute for Bioscience and Biotechnology Research, University of Maryland, MD, USA
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Young EM, Comer AD, Huang H, Alper HS. A molecular transporter engineering approach to improving xylose catabolism in Saccharomyces cerevisiae. Metab Eng 2012; 14:401-11. [DOI: 10.1016/j.ymben.2012.03.004] [Citation(s) in RCA: 85] [Impact Index Per Article: 7.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/30/2011] [Revised: 02/14/2012] [Accepted: 03/09/2012] [Indexed: 01/11/2023]
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Xiao H, Li Z, Jiang Y, Yang Y, Jiang W, Gu Y, Yang S. Metabolic engineering of D-xylose pathway in Clostridium beijerinckii to optimize solvent production from xylose mother liquid. Metab Eng 2012; 14:569-78. [PMID: 22677452 DOI: 10.1016/j.ymben.2012.05.003] [Citation(s) in RCA: 75] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/20/2012] [Revised: 04/29/2012] [Accepted: 05/22/2012] [Indexed: 11/18/2022]
Abstract
Clostridium beijerinckii is an attractive butanol-producing microbe for its advantage in co-fermenting hexose and pentose sugars. However, this Clostridium strain exhibits undesired efficiency in utilizing D-xylose, one of the major building blocks contained in lignocellulosic materials. Here, we reported a useful metabolic engineering strategy to improve D-xylose consumption by C. beijerinckii. Gene cbei2385, encoding a putative D-xylose repressor XylR, was first disrupted in the C. beijerinckii NCIMB 8052, resulting in a significant increase in D-xylose consumption. A D-xylose proton-symporter (encoded by gene cbei0109) was identified and then overexpressed to further optimize D-xylose utilization, yielding an engineered strain 8052xylR-xylT(ptb) (xylR inactivation plus xylT overexpression driven by ptb promoter). We investigated the strain 8052xylR-xylT(ptb) in fermenting xylose mother liquid, an abundant by-product from industrial-scale xylose preparation from corncob and rich in D-xylose, finally achieving a 35% higher Acetone, Butanol and Ethanol (ABE) solvent titer (16.91 g/L) and a 38% higher yield (0.29 g/g) over those of the wild-type strain. The strategy used in this study enables C. beijerinckii more suitable for butanol production from lignocellulosic materials.
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Affiliation(s)
- Han Xiao
- Key Laboratory of Synthetic Biology, Institute of Plant Physiology and Ecology, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, Shanghai 200032, China
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Systems metabolic engineering of microorganisms for natural and non-natural chemicals. Nat Chem Biol 2012; 8:536-46. [PMID: 22596205 DOI: 10.1038/nchembio.970] [Citation(s) in RCA: 507] [Impact Index Per Article: 42.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
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Jin M, Balan V, Gunawan C, Dale BE. Quantitatively understanding reduced xylose fermentation performance in AFEX™ treated corn stover hydrolysate using Saccharomyces cerevisiae 424A (LNH-ST) and Escherichia coli KO11. BIORESOURCE TECHNOLOGY 2012; 111:294-300. [PMID: 22366603 DOI: 10.1016/j.biortech.2012.01.154] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/08/2011] [Revised: 01/25/2012] [Accepted: 01/25/2012] [Indexed: 05/05/2023]
Abstract
Reduced xylose fermentation performance has been an issue during fermentation of AFEX™ hydrolysate using Saccharomyces cerevisiae 424A (LNH-ST) or Escherichia coli KO11. To better understand why fermentation performance is reduced, we quantitatively studied the effects of compounds present in the fermentation broth on xylose consumption. The compounds include biomass degradation products, ethanol and fermentation metabolites. The xylose consumption capability of E. coli KO11 was almost totally inhibited by the presence of both degradation products and ethanol. On the other hand, for S. cerevisiae 424A, 89% reduction of xylose consumption rate was found during hydrolysate fermentation. Degradation products, ethanol and fermentation metabolites were responsible for 32%, 24% and 33% of such reduction, respectively. Those results suggest that to further improve the xylose fermentation in hydrolysate, strains should be selected not only for degradation products tolerance but also for ethanol and fermentation metabolites tolerance.
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Affiliation(s)
- Mingjie Jin
- Biomass Conversion Research Laboratory (BCRL), Department of Chemical Engineering and Materials Science, Michigan State University, University Corporate Research Complex, 3900 Collins Road, Lansing, MI 48910, USA.
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Lindner SN, Seibold GM, Henrich A, Krämer R, Wendisch VF. Phosphotransferase system-independent glucose utilization in corynebacterium glutamicum by inositol permeases and glucokinases. Appl Environ Microbiol 2011; 77:3571-81. [PMID: 21478323 PMCID: PMC3127631 DOI: 10.1128/aem.02713-10] [Citation(s) in RCA: 86] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/19/2010] [Accepted: 03/26/2011] [Indexed: 12/30/2022] Open
Abstract
Phosphoenolpyruvate-dependent glucose phosphorylation via the phosphotransferase system (PTS) is the major path of glucose uptake in Corynebacterium glutamicum, but some growth from glucose is retained in the absence of the PTS. The growth defect of a deletion mutant lacking the general PTS component HPr in glucose medium could be overcome by suppressor mutations leading to the high expression of inositol utilization genes or by the addition of inositol to the growth medium if a glucokinase is overproduced simultaneously. PTS-independent glucose uptake was shown to require at least one of the inositol transporters IolT1 and IolT2 as a mutant lacking IolT1, IolT2, and the PTS component HPr could not grow with glucose as the sole carbon source. Efficient glucose utilization in the absence of the PTS necessitated the overexpression of a glucokinase gene in addition to either iolT1 or iolT2. IolT1 and IolT2 are low-affinity glucose permeases with K(s) values of 2.8 and 1.9 mM, respectively. As glucose uptake and phosphorylation via the PTS differs from glucose uptake via IolT1 or IolT2 and phosphorylation via glucokinase by the requirement for phosphoenolpyruvate, the roles of the two pathways for l-lysine production were tested. The l-lysine yield by C. glutamicum DM1729, a rationally engineered l-lysine-producing strain, was lower than that by its PTS-deficient derivate DM1729Δhpr, which, however, showed low production rates. The combined overexpression of iolT1 or iolT2 with ppgK, the gene for PolyP/ATP-dependent glucokinase, in DM1729Δhpr enabled l-lysine production as fast as that by the parent strain DM1729 but with 10 to 20% higher l-lysine yield.
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Affiliation(s)
- Steffen N. Lindner
- Chair of Genetics of Prokaryotes, Faculty of Biology & CeBiTec, Bielefeld University, D-33501 Bielefeld, Germany
| | - Gerd M. Seibold
- Institute of Biochemistry, University of Cologne, D-50674 Cologne, Germany
| | - Alexander Henrich
- Institute of Biochemistry, University of Cologne, D-50674 Cologne, Germany
| | - Reinhard Krämer
- Institute of Biochemistry, University of Cologne, D-50674 Cologne, Germany
| | - Volker F. Wendisch
- Chair of Genetics of Prokaryotes, Faculty of Biology & CeBiTec, Bielefeld University, D-33501 Bielefeld, Germany
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Trends and challenges in the microbial production of lignocellulosic bioalcohol fuels. Appl Microbiol Biotechnol 2010; 87:1303-15. [DOI: 10.1007/s00253-010-2707-z] [Citation(s) in RCA: 256] [Impact Index Per Article: 18.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/09/2010] [Revised: 05/27/2010] [Accepted: 05/27/2010] [Indexed: 12/30/2022]
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