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Asefi S, Nouri H, Pourmohammadi G, Moghimi H. Comprehensive network of stress-induced responses in Zymomonas mobilis during bioethanol production: from physiological and molecular responses to the effects of system metabolic engineering. Microb Cell Fact 2024; 23:180. [PMID: 38890644 PMCID: PMC11186258 DOI: 10.1186/s12934-024-02459-1] [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: 10/05/2023] [Accepted: 06/13/2024] [Indexed: 06/20/2024] Open
Abstract
Nowadays, biofuels, especially bioethanol, are becoming increasingly popular as an alternative to fossil fuels. Zymomonas mobilis is a desirable species for bioethanol production due to its unique characteristics, such as low biomass production and high-rate glucose metabolism. However, several factors can interfere with the fermentation process and hinder microbial activity, including lignocellulosic hydrolysate inhibitors, high temperatures, an osmotic environment, and high ethanol concentration. Overcoming these limitations is critical for effective bioethanol production. In this review, the stress response mechanisms of Z. mobilis are discussed in comparison to other ethanol-producing microbes. The mechanism of stress response is divided into physiological (changes in growth, metabolism, intracellular components, and cell membrane structures) and molecular (up and down-regulation of specific genes and elements of the regulatory system and their role in expression of specific proteins and control of metabolic fluxes) changes. Systemic metabolic engineering approaches, such as gene manipulation, overexpression, and silencing, are successful methods for building new metabolic pathways. Therefore, this review discusses systems metabolic engineering in conjunction with systems biology and synthetic biology as an important method for developing new strains with an effective response mechanism to fermentation stresses during bioethanol production. Overall, understanding the stress response mechanisms of Z. mobilis can lead to more efficient and effective bioethanol production.
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Affiliation(s)
- Shaqayeq Asefi
- Department of Microbial Biotechnology, School of Biology, College of Science, University of Tehran, Tehran, Iran
| | - Hoda Nouri
- Department of Microbial Biotechnology, School of Biology, College of Science, University of Tehran, Tehran, Iran.
| | - Golchehr Pourmohammadi
- Department of Microbial Biotechnology, School of Biology, College of Science, University of Tehran, Tehran, Iran
| | - Hamid Moghimi
- Department of Microbial Biotechnology, School of Biology, College of Science, University of Tehran, Tehran, Iran.
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Yi X, Yang D, Xu X, Wang Y, Guo Y, Zhang M, Wang Y, He Y, Zhu J. Cold plasma pretreatment reinforces the lignocellulose-derived aldehyde inhibitors tolerance and bioethanol fermentability for Zymomonas mobilis. BIOTECHNOLOGY FOR BIOFUELS AND BIOPRODUCTS 2023; 16:102. [PMID: 37322470 DOI: 10.1186/s13068-023-02354-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/14/2023] [Accepted: 05/29/2023] [Indexed: 06/17/2023]
Abstract
BACKGROUND Lignocellulose-derived aldehyde inhibitors seriously blocked the biorefinery of biofuels and biochemicals. To date, the economic production of lignocellulose-based products heavily relied on high productivities of fermenting strains. However, it was expensive and time-consuming for the achievable rational modification to strengthen stress tolerance robustness of aldehyde inhibitors. Here, it aimed to improve aldehyde inhibitors tolerance and cellulosic bioethanol fermentability for the chassis Zymomonas mobilis ZM4 pretreated using energy-efficient and eco-friendly cold plasma. RESULTS It was found that bioethanol fermentability was weaker in CSH (corn stover hydrolysates) than that in synthetic medium for Z. mobilis, and thus was attributed to the inhibition of the lignocellulose-derived aldehyde inhibitors in CSH. Convincingly, it further confirmed that the mixed aldehydes severely decreased bioethanol accumulation through additional aldehydes supplementary assays in synthetic medium. After assayed under different processing time (10-30 s), discharge power (80-160 W), and working pressure (120-180 Pa) using cold atmosphere plasma (CAP), it achieved the increased bioethanol fermentability for Z. mobilis after pretreated at the optimized parameters (20 s, 140 W and 165 Pa). It showed that cold plasma brought about three mutation sites including ZMO0694 (E220V), ZMO0843 (L471L) and ZMO0843 (P505H) via Genome resequencing-based SNPs (single nucleotide polymorphisms). A serial of differentially expressed genes (DEGs) were further identified as the potential contributors for stress tolerance via RNA-Seq sequencing, including ZMO0253 and ZMO_RS09265 (type I secretion outer membrane protein), ZMO1941 (Type IV secretory pathway protease TraF-like protein), ZMOr003 and ZMOr006 (16S ribosomal RNA), ZMO0375 and ZMO0374 (levansucrase) and ZMO1705 (thioredoxins). It enriched cellular process, followed by metabolic process and single-organism process for biological process. For KEGG analysis, the mutant was also referred to starch and sucrose metabolism, galactose metabolism and two-component system. Finally, but interestingly, it simultaneously achieved the enhanced stress tolerance capacity of aldehyde inhibitors and bioethanol fermentability in CSH for the mutant Z. mobilis. CONCLUSIONS Of several candidate genetic changes, the mutant Z. mobilis treated with cold plasma was conferred upon the facilitated aldehyde inhibitors tolerance and bioethanol production. This work would provide a strain biocatalyst for the efficient production of lignocellulosic biofuels and biochemicals.
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Affiliation(s)
- Xia Yi
- National-Local Joint Engineering Research Center for Biomass Refining and High-Quality Utilization, Changzhou University, Changzhou, 213164, China.
- Institute of Urban and Rural Mining, Changzhou University, Changzhou, 213164, China.
- Changzhou Key Laboratory of Biomass Green, Safe & High Value Utilization Technology, Changzhou University, Changzhou, 213164, Jiangsu, China.
| | - Dong Yang
- School of Pharmacy, Changzhou University, Changzhou, 213164, Jiangsu, China
| | - Xiaoyan Xu
- School of Pharmacy, Changzhou University, Changzhou, 213164, Jiangsu, China
| | - Youjun Wang
- School of Pharmacy, Changzhou University, Changzhou, 213164, Jiangsu, China
| | - Yan Guo
- School of Pharmacy, Changzhou University, Changzhou, 213164, Jiangsu, China
| | - Meng Zhang
- School of Pharmacy, Changzhou University, Changzhou, 213164, Jiangsu, China
| | - Yilong Wang
- School of Pharmacy, Changzhou University, Changzhou, 213164, Jiangsu, China
| | - Yucai He
- National-Local Joint Engineering Research Center for Biomass Refining and High-Quality Utilization, Changzhou University, Changzhou, 213164, China.
- School of Pharmacy, Changzhou University, Changzhou, 213164, Jiangsu, China.
| | - Jie Zhu
- National-Local Joint Engineering Research Center for Biomass Refining and High-Quality Utilization, Changzhou University, Changzhou, 213164, China.
- Institute of Urban and Rural Mining, Changzhou University, Changzhou, 213164, China.
- Changzhou Key Laboratory of Biomass Green, Safe & High Value Utilization Technology, Changzhou University, Changzhou, 213164, Jiangsu, China.
- School of Pharmacy, Changzhou University, Changzhou, 213164, Jiangsu, China.
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3
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Shan W, Yan Y, Li Y, Hu W, Chen J. Microbial tolerance engineering for boosting lactic acid production from lignocellulose. BIOTECHNOLOGY FOR BIOFUELS AND BIOPRODUCTS 2023; 16:78. [PMID: 37170163 PMCID: PMC10173534 DOI: 10.1186/s13068-023-02334-y] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/21/2023] [Accepted: 04/28/2023] [Indexed: 05/13/2023]
Abstract
Lignocellulosic biomass is an attractive non-food feedstock for lactic acid production via microbial conversion due to its abundance and low-price, which can alleviate the conflict with food supplies. However, a variety of inhibitors derived from the biomass pretreatment processes repress microbial growth, decrease feedstock conversion efficiency and increase lactic acid production costs. Microbial tolerance engineering strategies accelerate the conversion of carbohydrates by improving microbial tolerance to toxic inhibitors using pretreated lignocellulose hydrolysate as a feedstock. This review presents the recent significant progress in microbial tolerance engineering to develop robust microbial cell factories with inhibitor tolerance and their application for cellulosic lactic acid production. Moreover, microbial tolerance engineering crosslinking other efficient breeding tools and novel approaches are also deeply discussed, aiming to providing a practical guide for economically viable production of cellulosic lactic acid.
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Affiliation(s)
- Wenwen Shan
- Department of Biophysics, Institute of Modern Physics, Chinese Academy of Sciences, 509 Nanchang Road, Lanzhou, 730000, People's Republic of China
- University of Chinese Academy of Sciences, Beijing, People's Republic of China
| | - Yongli Yan
- Department of Biophysics, Institute of Modern Physics, Chinese Academy of Sciences, 509 Nanchang Road, Lanzhou, 730000, People's Republic of China
- University of Chinese Academy of Sciences, Beijing, People's Republic of China
| | - Yongda Li
- College of Food Science and Engineering, Gansu Agricultural University, Lanzhou, People's Republic of China
| | - Wei Hu
- Department of Biophysics, Institute of Modern Physics, Chinese Academy of Sciences, 509 Nanchang Road, Lanzhou, 730000, People's Republic of China.
- University of Chinese Academy of Sciences, Beijing, People's Republic of China.
| | - Jihong Chen
- Department of Biophysics, Institute of Modern Physics, Chinese Academy of Sciences, 509 Nanchang Road, Lanzhou, 730000, People's Republic of China.
- University of Chinese Academy of Sciences, Beijing, People's Republic of China.
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4
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Shabbir S, Wang W, Nawaz M, Boruah P, Kulyar MFEA, Chen M, Wu B, Liu P, Dai Y, Sun L, Gou Q, Liu R, Hu G, Younis T, He M. Molecular mechanism of engineered Zymomonas mobilis to furfural and acetic acid stress. Microb Cell Fact 2023; 22:88. [PMID: 37127628 PMCID: PMC10152622 DOI: 10.1186/s12934-023-02095-1] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/06/2023] [Accepted: 04/12/2023] [Indexed: 05/03/2023] Open
Abstract
Acetic acid and furfural (AF) are two major inhibitors of microorganisms during lignocellulosic ethanol production. In our previous study, we successfully engineered Zymomonas mobilis 532 (ZM532) strain by genome shuffling, but the molecular mechanisms of tolerance to inhibitors were still unknown. Therefore, this study investigated the responses of ZM532 and its wild-type Z. mobilis (ZM4) to AF using multi-omics approaches (transcriptomics, genomics, and label free quantitative proteomics). Based on RNA-Seq data, two differentially expressed genes, ZMO_RS02740 (up-regulated) and ZMO_RS06525 (down-regulated) were knocked out and over-expressed through CRISPR-Cas technology to investigate their roles in AF tolerance. Overall, we identified 1865 and 14 novel DEGs in ZM532 and wild-type ZM4. In contrast, 1532 proteins were identified in ZM532 and wild-type ZM4. Among these, we found 96 important genes in ZM532 involving acid resistance mechanisms and survival rates against stressors. Furthermore, our knockout results demonstrated that growth activity and glucose consumption of mutant strains ZM532∆ZMO_RS02740 and ZM4∆ZMO_RS02740 decreased with increased fermentation time from 42 to 55 h and ethanol production up to 58% in ZM532 than that in ZM532∆ZMO_RS02740. Hence, these findings suggest ZMO_RS02740 as a protective strategy for ZM ethanol production under stressful conditions.
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Affiliation(s)
- Samina Shabbir
- Graduate School of Chinese Academy of Agricultural Science, Beijing, 100081, People's Republic of China
- Department of Chemistry, The Women University Multan, Multan, Pakistan
| | - Weiting Wang
- Graduate School of Chinese Academy of Agricultural Science, Beijing, 100081, People's Republic of China
- Biomass Energy Technology Research Centre, Key Laboratory of Development and Application of Rural Renewable Energy (Ministry of Agriculture and Rural Affairs), Biogas Institute of Ministry of Agriculture and Rural Affairs, Section 4-13, Renmin Rd. South, Chengdu, 610041, People's Republic of China
| | - Mohsin Nawaz
- Institute of Environment and Ecology, School of the Environment and Safety Engineering, Jiangsu University, Zhenjiang, 212013, China
| | - Prerona Boruah
- School of Biotechnology and Bioinformatics, DY PATIL Deemed to Be University, Navi Mumbai, India
| | | | - Mao Chen
- Graduate School of Chinese Academy of Agricultural Science, Beijing, 100081, People's Republic of China
- Biomass Energy Technology Research Centre, Key Laboratory of Development and Application of Rural Renewable Energy (Ministry of Agriculture and Rural Affairs), Biogas Institute of Ministry of Agriculture and Rural Affairs, Section 4-13, Renmin Rd. South, Chengdu, 610041, People's Republic of China
| | - Bo Wu
- Biomass Energy Technology Research Centre, Key Laboratory of Development and Application of Rural Renewable Energy (Ministry of Agriculture and Rural Affairs), Biogas Institute of Ministry of Agriculture and Rural Affairs, Section 4-13, Renmin Rd. South, Chengdu, 610041, People's Republic of China
| | - Panting Liu
- Graduate School of Chinese Academy of Agricultural Science, Beijing, 100081, People's Republic of China
- Biomass Energy Technology Research Centre, Key Laboratory of Development and Application of Rural Renewable Energy (Ministry of Agriculture and Rural Affairs), Biogas Institute of Ministry of Agriculture and Rural Affairs, Section 4-13, Renmin Rd. South, Chengdu, 610041, People's Republic of China
| | - Yonghua Dai
- Graduate School of Chinese Academy of Agricultural Science, Beijing, 100081, People's Republic of China
- Biomass Energy Technology Research Centre, Key Laboratory of Development and Application of Rural Renewable Energy (Ministry of Agriculture and Rural Affairs), Biogas Institute of Ministry of Agriculture and Rural Affairs, Section 4-13, Renmin Rd. South, Chengdu, 610041, People's Republic of China
| | - Lingling Sun
- Graduate School of Chinese Academy of Agricultural Science, Beijing, 100081, People's Republic of China
- Biomass Energy Technology Research Centre, Key Laboratory of Development and Application of Rural Renewable Energy (Ministry of Agriculture and Rural Affairs), Biogas Institute of Ministry of Agriculture and Rural Affairs, Section 4-13, Renmin Rd. South, Chengdu, 610041, People's Republic of China
| | - Qiyu Gou
- Graduate School of Chinese Academy of Agricultural Science, Beijing, 100081, People's Republic of China
- Biomass Energy Technology Research Centre, Key Laboratory of Development and Application of Rural Renewable Energy (Ministry of Agriculture and Rural Affairs), Biogas Institute of Ministry of Agriculture and Rural Affairs, Section 4-13, Renmin Rd. South, Chengdu, 610041, People's Republic of China
| | - Renbin Liu
- Graduate School of Chinese Academy of Agricultural Science, Beijing, 100081, People's Republic of China
- Biomass Energy Technology Research Centre, Key Laboratory of Development and Application of Rural Renewable Energy (Ministry of Agriculture and Rural Affairs), Biogas Institute of Ministry of Agriculture and Rural Affairs, Section 4-13, Renmin Rd. South, Chengdu, 610041, People's Republic of China
| | - Guoquan Hu
- Graduate School of Chinese Academy of Agricultural Science, Beijing, 100081, People's Republic of China
- Biomass Energy Technology Research Centre, Key Laboratory of Development and Application of Rural Renewable Energy (Ministry of Agriculture and Rural Affairs), Biogas Institute of Ministry of Agriculture and Rural Affairs, Section 4-13, Renmin Rd. South, Chengdu, 610041, People's Republic of China
| | - Tahira Younis
- Department of Biochemistry and Biotechnology, The Women University Multan, Multan, Pakistan
| | - Mingxiong He
- Graduate School of Chinese Academy of Agricultural Science, Beijing, 100081, People's Republic of China.
- Chengdu National Agricultural Science and Technology Center, Chengdu, People's Republic of China.
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Liu L, Li JT, Li SH, Liu LP, Wu B, Wang YW, Yang SH, Chen CH, Tan FR, He MX. The potential use of Zymomonas mobilis for the food industry. Crit Rev Food Sci Nutr 2022; 64:4134-4154. [PMID: 36345974 DOI: 10.1080/10408398.2022.2139221] [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: 11/10/2022]
Abstract
Zymomonas mobilis is a gram-negative facultative anaerobic spore, which is generally recognized as a safe. As a promising ethanologenic organism for large-scale bio-ethanol production, Z. mobilis has also shown a good application prospect in food processing and food additive synthesis for its unique physiological characteristics and excellent industrial characteristics. It not only has obvious advantages in food processing and becomes the biorefinery chassis cell for food additives, but also has a certain healthcare effect on human health. Until to now, most of the research is still in theory and laboratory scale, and further research is also needed to achieve industrial production. This review summarized the physiological characteristics and advantages of Z. mobilis in food industry for the first time and further expounds its research status in food industry from three aspects of food additive synthesis, fermentation applications, and prebiotic efficacy, it will provide a theoretical basis for its development and applications in food industry. This review also discussed the shortcomings of its practical applications in the current food industry, and explored other ways to broaden the applications of Z. mobilis in the food industry, to promote its applications in food processing.
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Affiliation(s)
- Lu Liu
- Biomass Energy Technology Research Centre, Key Laboratory of Development and Application of Rural Renewable Energy (Ministry of Agriculture and Rural Affairs), Biogas Institute of Ministry of Agriculture and Rural Affairs, Chengdu, P.R. China
- College of Food and Bioengineering, Chengdu University, Chengdu, P.R. China
| | - Jian-Ting Li
- Biomass Energy Technology Research Centre, Key Laboratory of Development and Application of Rural Renewable Energy (Ministry of Agriculture and Rural Affairs), Biogas Institute of Ministry of Agriculture and Rural Affairs, Chengdu, P.R. China
| | - Sheng-Hao Li
- Biomass Energy Technology Research Centre, Key Laboratory of Development and Application of Rural Renewable Energy (Ministry of Agriculture and Rural Affairs), Biogas Institute of Ministry of Agriculture and Rural Affairs, Chengdu, P.R. China
| | - Lin-Pei Liu
- Biomass Energy Technology Research Centre, Key Laboratory of Development and Application of Rural Renewable Energy (Ministry of Agriculture and Rural Affairs), Biogas Institute of Ministry of Agriculture and Rural Affairs, Chengdu, P.R. China
| | - Bo Wu
- Biomass Energy Technology Research Centre, Key Laboratory of Development and Application of Rural Renewable Energy (Ministry of Agriculture and Rural Affairs), Biogas Institute of Ministry of Agriculture and Rural Affairs, Chengdu, P.R. China
| | - Yan-Wei Wang
- Biomass Energy Technology Research Centre, Key Laboratory of Development and Application of Rural Renewable Energy (Ministry of Agriculture and Rural Affairs), Biogas Institute of Ministry of Agriculture and Rural Affairs, Chengdu, P.R. China
| | - Shi-Hui Yang
- State Key Laboratory of Biocatalysis and Enzyme Engineering, and School of Life Sciences, Hubei University, Wuhan, Hubei, P.R. China
| | - Cheng-Han Chen
- Biomass Energy Technology Research Centre, Key Laboratory of Development and Application of Rural Renewable Energy (Ministry of Agriculture and Rural Affairs), Biogas Institute of Ministry of Agriculture and Rural Affairs, Chengdu, P.R. China
| | - Fu-Rong Tan
- Biomass Energy Technology Research Centre, Key Laboratory of Development and Application of Rural Renewable Energy (Ministry of Agriculture and Rural Affairs), Biogas Institute of Ministry of Agriculture and Rural Affairs, Chengdu, P.R. China
| | - Ming-Xiong He
- Biomass Energy Technology Research Centre, Key Laboratory of Development and Application of Rural Renewable Energy (Ministry of Agriculture and Rural Affairs), Biogas Institute of Ministry of Agriculture and Rural Affairs, Chengdu, P.R. China
- College of Food and Bioengineering, Chengdu University, Chengdu, P.R. China
- Institute of Ecological Environment, Chengdu University of Technology, Chengdu, P.R. China
- Chengdu National Agricultural Science and Technology Center, Chengdu, P.R. China
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6
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Zou L, Jin X, Tao Y, Zheng Z, Ouyang J. Unraveling the mechanism of furfural tolerance in engineered Pseudomonas putida by genomics. Front Microbiol 2022; 13:1035263. [PMID: 36338095 PMCID: PMC9630843 DOI: 10.3389/fmicb.2022.1035263] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/02/2022] [Accepted: 09/30/2022] [Indexed: 07/24/2023] Open
Abstract
As a dehydration product of pentoses in hemicellulose sugar streams derived from lignocellulosic biomass, furfural is a prevalent inhibitor in the efficient microbial conversion process. To solve this obstacle, exploiting a biorefinery strain with remarkable furfural tolerance capability is essential. Pseudomonas putida KT2440 (P. putida) has served as a valuable bacterial chassis for biomass biorefinery. Here, a high-concentration furfural-tolerant P. putida strain was developed via adaptive laboratory evolution (ALE). The ALE resulted in a previously engineered P. putida strain with substantially increased furfural tolerance as compared to wild-type. Whole-genome sequencing of the adapted strains and reverse engineering validation of key targets revealed for the first time that several genes and their mutations, especially for PP_RS19785 and PP_RS18130 [encoding ATP-binding cassette (ABC) transporters] as well as PP_RS20740 (encoding a hypothetical protein), play pivotal roles in the furfural tolerance and conversion of this bacterium. Finally, strains overexpressing these three striking mutations grew well in highly toxic lignocellulosic hydrolysate, with cell biomass around 9-, 3.6-, and two-fold improvement over the control strain, respectively. To our knowledge, this study first unravels the furan aldehydes tolerance mechanism of industrial workhorse P. putida, which provides a new foundation for engineering strains to enhance furfural tolerance and further facilitate the valorization of lignocellulosic biomass.
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7
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Hu D, Wang Z, He M, Ma Y. Functional Gene Identification and Corresponding Tolerant Mechanism of High Furfural-Tolerant Zymomonas mobilis Strain F211. Front Microbiol 2021; 12:736583. [PMID: 34858360 PMCID: PMC8631904 DOI: 10.3389/fmicb.2021.736583] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/03/2021] [Accepted: 10/15/2021] [Indexed: 12/21/2022] Open
Abstract
Furfural is a major inhibitor in lignocellulose hydrolysate for Zymomonas mobilis. A mutant F211 strain with high furfural tolerance was obtained from our previous study. Thus, its key tolerance mechanism was studied in the present study. The function of mutated genes in F211 was identified by functional complementation experiments, revealing that the improved furfural tolerance was resulted from the C493T mutation of the ZCP4_0270 gene promoting cell flocculation and the mutation (G1075A)/downregulation of ZCP4_0970. Comparative transcriptome analysis revealed 139 differentially expressed genes between F211 and the control, CP4, in response to furfural stress. In addition, the reliability of the RNA-Seq data was also confirmed. The potential tolerance mechanism was further demonstrated by functional identification of tolerance genes as follows: (I) some upregulated or downregulated genes increase the levels of NAD(P)H, which is involved in the reduction of furfural to less toxic furfuryl alcohol, thus accelerating the detoxification of furfural; (II) the mutated ZCP4_0270 and upregulated cellulose synthetase gene (ZCP4_0241 and ZCP4_0242) increased flocculation to resist furfural stress; (III) upregulated molecular chaperone genes promote protein synthesis and repair stress-damaged proteins; and (IV) transporter genes ZCP4_1623–1,625 and ZCP4_1702–1703 were downregulated, saving energy for cell growth. The furfural-tolerant mechanism and corresponding functional genes were revealed, which provides a theoretical basis for developing robust chassis strains for synthetic biology efforts.
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Affiliation(s)
- Dongsheng Hu
- Department of Biochemical Engineering, School of Chemical Engineering and Technology, Tianjin University, Tianjin, China
| | - Zhiquan Wang
- Department of Biochemical Engineering, School of Chemical Engineering and Technology, Tianjin University, Tianjin, China.,School of Marine Science and Technology, Tianjin University, Tianjin, China
| | - Mingxiong He
- Biomass Energy Technology Research Centre, Key Laboratory of Development and Application of Rural Renewable Energy (Ministry of Agriculture and Rural Affairs), Biogas Institute of Ministry of Agriculture and Rural Affairs, Chengdu, China
| | - Yuanyuan Ma
- Department of Biochemical Engineering, School of Chemical Engineering and Technology, Tianjin University, Tianjin, China.,School of Marine Science and Technology, Tianjin University, Tianjin, China
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8
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Tran VG, Zhao H. Engineering robust microorganisms for organic acid production. J Ind Microbiol Biotechnol 2021; 49:6373449. [PMID: 34549297 PMCID: PMC9118992 DOI: 10.1093/jimb/kuab067] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/17/2021] [Accepted: 09/11/2021] [Indexed: 11/24/2022]
Abstract
Organic acids are an important class of compounds that can be produced by microbial conversion of renewable feedstocks and have huge demands and broad applications in food, chemical, and pharmaceutical industries. An economically viable fermentation process for production of organic acids requires robust microbial cell factories with excellent tolerance to low pH conditions, high concentrations of organic acids, and lignocellulosic inhibitors. In this review, we summarize various strategies to engineer robust microorganisms for organic acid production and highlight their applications in a few recent examples.
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Affiliation(s)
- Vinh G Tran
- Department of Chemical and Biomolecular Engineering, U.S. Department of Energy Center for Bioenergy and Bioproducts Innovation (CABBI), Carl R. Woese Institute for Genomic Biology, University of Illinois at Urbana-Champaign, Urbana, IL 61801, United States
| | - Huimin Zhao
- Department of Chemical and Biomolecular Engineering, U.S. Department of Energy Center for Bioenergy and Bioproducts Innovation (CABBI), Carl R. Woese Institute for Genomic Biology, University of Illinois at Urbana-Champaign, Urbana, IL 61801, United States.,Departments of Chemistry, Biochemistry, and Bioengineering, University of Illinois at Urbana-Champaign, Urbana, IL 61801, United States
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9
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Wang Y, Li Q, Tian P, Tan T. Charting the landscape of RNA polymerases to unleash their potential in strain improvement. Biotechnol Adv 2021; 54:107792. [PMID: 34216775 DOI: 10.1016/j.biotechadv.2021.107792] [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: 02/16/2021] [Revised: 05/28/2021] [Accepted: 06/26/2021] [Indexed: 11/19/2022]
Abstract
One major mission of microbial cell factory is overproduction of desired chemicals. To this end, it is necessary to orchestrate enzymes that affect metabolic fluxes. However, only modification of a small number of enzymes in most cases cannot maximize desired metabolites, and global regulation is required. Of myriad enzymes influencing global regulation, RNA polymerase (RNAP) may be the most versatile enzyme in biological realm because it not only serves as the workhorse of central dogma but also participates in a plethora of biochemical events. In fact, recent years have witnessed extensive exploitation of RNAPs for phenotypic engineering. While a few impressive reviews showcase the structures and functionalities of RNAPs, this review not only summarizes the state-of-the-art advance in the structures of RNAPs but also points out their enormous potentials in metabolic engineering and synthetic biology. This review aims to provide valuable insights for strain improvement.
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Affiliation(s)
- Ye Wang
- Beijing Key Laboratory of Bioprocess, College of Life Science and Technology, Beijing University of Chemical Technology, Beijing 100029, PR China
| | - Qingyang Li
- School of Food Science and Engineering, South China University of Technology, Guangzhou 510641, PR China
| | - Pingfang Tian
- Beijing Key Laboratory of Bioprocess, College of Life Science and Technology, Beijing University of Chemical Technology, Beijing 100029, PR China.
| | - Tianwei Tan
- Beijing Key Laboratory of Bioprocess, College of Life Science and Technology, Beijing University of Chemical Technology, Beijing 100029, PR China
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10
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Yan Z, Zhang J, Bao J. Increasing cellulosic ethanol production by enhancing phenolic tolerance of Zymomonas mobilis in adaptive evolution. BIORESOURCE TECHNOLOGY 2021; 329:124926. [PMID: 33684841 DOI: 10.1016/j.biortech.2021.124926] [Citation(s) in RCA: 15] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/21/2021] [Revised: 02/24/2021] [Accepted: 02/25/2021] [Indexed: 06/12/2023]
Abstract
Cellulosic ethanol fermentability of ethanologenic strain Zymomonas mobilis is severely inhibited by phenolic aldehydes generated from lignocellulose pretreatment. Here, a 198 days' laboratory adaptive evolution of Z. mobilis 8b in corn stover hydrolysate was conducted to increase its phenolic aldehydes tolerance and ethanol fermentability. The obtained Z. mobilis Z198 demonstrated a significantly improved conversion of the most toxic phenolic aldehyde (vanillin) by 6.3-fold and cellulosic ethanol production by 21.6%. The transcriptional analysis using qRT-PCR revealed that the gene ZMO3_RS07160 encoding SDR family oxidoreductase in Z. mobilis Z198 was significantly up-regulated by 11.7-fold. The overexpression of ZMO3_RS07160 in the parental Z. mobilis increased the ethanol fermentability to that of the adaptively evolved strain Z. mobilis Z198. This study provided a practical method to obtain a robust cellulosic ethanol fermenting strain, and a candidate gene for synthetic biology of biorefinery strains with strong phenolic aldehydes tolerance.
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Affiliation(s)
- Zhao Yan
- State Key Laboratory of Bioreactor Engineering, East China University of Science and Technology, 130 Meilong Road, Shanghai 200237, China
| | - Jian Zhang
- State Key Laboratory of Bioreactor Engineering, East China University of Science and Technology, 130 Meilong Road, Shanghai 200237, China
| | - Jie Bao
- State Key Laboratory of Bioreactor Engineering, East China University of Science and Technology, 130 Meilong Road, Shanghai 200237, China.
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Metabolic engineering of Zymomonas moblis for ethylene production from straw hydrolysate. Appl Microbiol Biotechnol 2021; 105:1709-1720. [PMID: 33512573 DOI: 10.1007/s00253-021-11091-7] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/02/2020] [Revised: 10/27/2020] [Accepted: 01/03/2021] [Indexed: 10/22/2022]
Abstract
Biological ethylene production is a promising sustainable alternative approach for fossil-based ethylene production. The high glucose utilization of Z. mobilis makes it as a promising bioethylene producer. In this study, Zymomonas mobilis has been engineered to produce ethylene through the introduction of the synthetic ethylene-forming enzyme (EFE). We also investigated the effect of systematically knocking out the competitive metabolic pathway of pyruvate in an effort to improve the availability of pyruvate for ethylene production in Z. mobilis expressing EFE. Guided by these results, we tested a number of conjectures that could improve the α-ketoglutarate supply. Optimization of these pathways and different substrate supplies resulted in a greater production of ethylene (from 1.36 to 12.83 nmol/OD600/mL), which may guide future engineering work on ethylene production using other organisms. Meanwhile, we achieved an ethylene production of 5.8 nmol/OD600/mL in the ZM532-efe strain using enzymatic straw hydrolysate of corn straw as the sole carbon source. As a preferred host in biorefinery technologies using lignocellulosic biomass as feedstock, heterologous expression of EFE in Z. mobilis converts the non-ethylene producing strain into an ethylene-producing one using a metabolic engineering approach, which is of great significance for the utilization of cellulosic biomass in the future. KEY POINTS: • Heterologous expression of EFE in Z. mobilis successfully converted the non-ethylene producing strain into an ethylene producer (1.36 nmol/OD600/mL). Targeted modifications of the central carbon metabolism can effectively improve ethylene production (peak production: 8.3 nmol/OD600/mL). • The addition of nutrients to the medium can further increase the production of ethylene (peak production: 12.8 nmol/OD600/mL). • The ZM532-efe strain achieved an ethylene production of 5.8 nmol/OD600/mL when enzymatic hydrolysate of corn straw was used as the sole carbon source.
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12
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Nouri H, Moghimi H, Marashi SA, Elahi E. Impact of hfq and sigE on the tolerance of Zymomonas mobilis ZM4 to furfural and acetic acid stresses. PLoS One 2020; 15:e0240330. [PMID: 33035245 PMCID: PMC7546472 DOI: 10.1371/journal.pone.0240330] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/15/2020] [Accepted: 09/23/2020] [Indexed: 01/14/2023] Open
Abstract
Zymomonas mobilis, as an ethanologenic microorganism with many desirable industrial features, faces crucial obstacles in the lignocellulosic ethanol production process. A significant hindrance occurs during the pretreatment procedure that not only produces fermentable sugars but also releases severe toxic compounds. As diverse parts of regulation networks are involved in different aspects of complicated tolerance to inhibitors, we developed ZM4-hfq and ZM4-sigE strains, in which hfq and sigE genes were overexpressed, respectively. ZM4-hfq is a transcription regulator and ZM4-sigE is a transcription factor that are involved in multiple stress responses. In the present work, by overexpressing these two genes, we evaluated their impact on the Z. mobilis tolerance to furfural, acetic acid, and sugarcane bagasse hydrolysates. Both recombinant strains showed increased growth rates and ethanol production levels compared to the parental strain. Under a high concentration of furfural, the growth rate of ZM4-hfq was more inhibited compared to ZM4-sigE. More precisely, fermentation performance of ZM4-hfq revealed that the yield of ethanol production was less than that of ZM4-sigE, because more unused sugar had remained in the medium. In the case of acetic acid, ZM4-sigE was the superior strain and produced four and two-fold more ethanol compared to the parental strain and ZM4-hfq, respectively. Comparison of inhibitor tolerance between single and multiple toxic inhibitors in the fermentation of sugarcane bagasse hydrolysate by ZM4-sigE strain showed similar results. In addition, ethanol production performance was considerably higher in ZM4-sigE as well. Finally, the results of the qPCR analysis suggested that under both furfural and acetic acid treatment experiments, overproduction of both hfq and sigE improves the Z. mobilis tolerance and its ethanol production capability. Overall, our study showed the vital role of the regulatory elements to overcome the obstacles in lignocellulosic biomass-derived ethanol and provide a platform for further improvement by directed evolution or systems metabolic engineering tools.
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Affiliation(s)
- Hoda Nouri
- Department of Microbial Biotechnology, School of Biology, College of Science, University of Tehran, Tehran, Iran
| | - Hamid Moghimi
- Department of Microbial Biotechnology, School of Biology, College of Science, University of Tehran, Tehran, Iran
- * E-mail:
| | - Sayed-Amir Marashi
- Department of Biotechnology, College of Science, University of Tehran, Tehran, Iran
| | - Elahe Elahi
- School of Biology, College of Science, University of Tehran, Tehran, Iran
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13
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Todhanakasem T, Wu B, Simeon S. Perspectives and new directions for bioprocess optimization using Zymomonas mobilis in the ethanol production. World J Microbiol Biotechnol 2020; 36:112. [PMID: 32656581 DOI: 10.1007/s11274-020-02885-4] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/19/2020] [Accepted: 06/29/2020] [Indexed: 12/28/2022]
Abstract
Zymomonas mobilis is an ethanologenic microbe that has a demonstrated potential for use in lignocellulosic biorefineries for bioethanol production. Z. mobilis exhibits a number of desirable characteristics for use as an ethanologenic microbe, with capabilities for metabolic engineering and bioprocess modification. Many advanced genetic tools, including mutation techniques, screening methods and genome editing have been successively performed to improve various Z. mobilis strains as potential consolidated ethanologenic microbes. Many bioprocess strategies have also been applied to this organism for bioethanol production. Z. mobilis biofilm reactors have been modified with various benefits, including high bacterial populations, less fermentation times, high productivity, high cell stability, resistance to the high concentration of substrates and toxicity, and higher product recovery. We suggest that Z. mobilis biofilm reactors could be used in bioethanol production using lignocellulosic substrates under batch, continuous and repeated batch processes.
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Affiliation(s)
- Tatsaporn Todhanakasem
- Department of Agro- Industry, Faculty of Biotechnology, Assumption University, Ramkhamhaeng Road, Bangkapi, Bangkok, 10240, Thailand.
| | - Bo Wu
- Biomass Energy Technology Research Center, Biogas Institute of Ministry of Agriculture and Rural Affairs, Renmin Rd. S 4-13, Chengdu, 610041, China
| | - Saw Simeon
- Absolute Clean Energy Public Company Limited, ITF Tower 7th Floor, Silom Road, Bang Rak, Bangkok, 10500, Thailand
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14
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Wang WT, Dai LC, Wu B, Qi BF, Huang TF, Hu GQ, He MX. Biochar-mediated enhanced ethanol fermentation (BMEEF) in Zymomonas mobilis under furfural and acetic acid stress. BIOTECHNOLOGY FOR BIOFUELS 2020; 13:28. [PMID: 32127915 PMCID: PMC7045489 DOI: 10.1186/s13068-020-1666-6] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/08/2019] [Accepted: 01/22/2020] [Indexed: 05/19/2023]
Abstract
BACKGROUND Pretreatment of lignocellulosic biomass generates different types of inhibitors (e.g., furfural and acetic acid), which could remarkably inhibit subsequent ethanol fermentation. Here, biochar as an additive in the fermentation broth was first applied to enhance ethanol production by Z. mobilis wild-type strain ZM4 in the presence of typical inhibitors. RESULTS This study showed that the biochar-mediated tolerance to furfural and acetic acid for the strain Z. mobilis ZM4 was the highest reported level, resulting in much higher ethanol productivity under stress conditions than that in non-treated conditions. Further analysis showed that adsorptive detoxification was not the controlling factor for enhanced ethanol production under stress conditions, attributed to its low removal of furfural (< 20%) and incapability of acetic acid removal. When biochar was filtered from the biochar-treated inhibitor-containing broth, it still showed enhanced ethanol production. Furthermore, Z. mobilis immobilized on biochar was also observed. Thus, biochar extracts in the fermentation broth and cell immobilization on biochar might be the controlling factors for enhanced ethanol production under stress conditions. CONCLUSIONS These results indicate that biochar-mediated enhanced ethanol fermentation (BMEEF) might be a promising strategy for ethanol production from lignocellulosic biomass.
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Affiliation(s)
- Wei-ting Wang
- Biomass Energy Technology Research Centre, Key Laboratory of Development and Application of Rural Renewable Energy (Ministry of Agriculture and Rural Affairs), Biogas Institute of Ministry of Agriculture and Rural Affairs, Section 4-13, Renmin Rd. South, Chengdu, 610041 People’s Republic of China
- Graduate School of Chinese Academy of Agricultural Science, Beijing, 100081 People’s Republic of China
| | - Li-chun Dai
- Biomass Energy Technology Research Centre, Key Laboratory of Development and Application of Rural Renewable Energy (Ministry of Agriculture and Rural Affairs), Biogas Institute of Ministry of Agriculture and Rural Affairs, Section 4-13, Renmin Rd. South, Chengdu, 610041 People’s Republic of China
| | - Bo Wu
- Biomass Energy Technology Research Centre, Key Laboratory of Development and Application of Rural Renewable Energy (Ministry of Agriculture and Rural Affairs), Biogas Institute of Ministry of Agriculture and Rural Affairs, Section 4-13, Renmin Rd. South, Chengdu, 610041 People’s Republic of China
| | - Bu-fan Qi
- College of Pharmacy and Biological Engineering, Chengdu University, No. 2025, Cheng Luo Road, Chengdu, 610106 People’s Republic of China
| | - Tian-fang Huang
- Chengdu Institute of Biology, Chinese Academy of Sciences, Section 4-9, Renmin Rd. South, Chengdu, 610041 People’s Republic of China
| | - Guo-quan Hu
- Biomass Energy Technology Research Centre, Key Laboratory of Development and Application of Rural Renewable Energy (Ministry of Agriculture and Rural Affairs), Biogas Institute of Ministry of Agriculture and Rural Affairs, Section 4-13, Renmin Rd. South, Chengdu, 610041 People’s Republic of China
| | - Ming-xiong He
- Biomass Energy Technology Research Centre, Key Laboratory of Development and Application of Rural Renewable Energy (Ministry of Agriculture and Rural Affairs), Biogas Institute of Ministry of Agriculture and Rural Affairs, Section 4-13, Renmin Rd. South, Chengdu, 610041 People’s Republic of China
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15
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Yang S, Franden MA, Wang X, Chou YC, Hu Y, Brown SD, Pienkos PT, Zhang M. Transcriptomic Profiles of Zymomonas mobilis 8b to Furfural Acute and Long-Term Stress in Both Glucose and Xylose Conditions. Front Microbiol 2020; 11:13. [PMID: 32038596 PMCID: PMC6989614 DOI: 10.3389/fmicb.2020.00013] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/05/2019] [Accepted: 01/06/2020] [Indexed: 12/14/2022] Open
Abstract
Zymomonas mobilis 8b is an ethanologenic bacterium engineered to utilize both glucose and xylose. The impacts of lignocellulosic hydrolyzate inhibitors on the growth of Zymomonas mobilis 8b have been investigated. However, the molecular responses of these inhibitors have not been completely elucidated yet. In this study, molecular responses to furfural were investigated using transcriptomic approaches of both chip-based microarray and a directional mRNA-Seq. Furfural acute shock time-course experiment with 3 g/L furfural supplemented when cells reached exponential phase and stress response experiment in the presence of 2 g/L furfural from the beginning of fermentation were carried out to study the physiological and transcriptional profiles of short-term and long-term effects of furfural on 8b. Furfural negatively affected 8b growth in terms of final biomass and the fermentation time. Transcriptomic studies indicated that the response of 8b to furfural was dynamic and complex, and differences existed between short-term shock and long-term stress responses. However, the gene function categories were similar with most down-regulated genes related to translation and biosynthesis, while the furfural up-regulated genes were mostly related to general stress responses. Several gene candidates have been identified and genetic studies indicated that expression of ZMO0465 and cysteine synthase operon ZMO0003-0006 driven by its native promoter in a shuttle vector enhanced the furfural tolerance of 8b. In addition, the relationship between microarray and mRNA-Seq was compared with good correlations. The directional mRNA-Seq data not only provided the gene expression profiling, but also can be applied for transcriptional architecture improvement to identify and confirm operons, novel transcripts, hypothetical gene functions, transcriptional start sites, and promoters with different strength.
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Affiliation(s)
- Shihui Yang
- State Key Laboratory of Biocatalysis and Enzyme Engineering, Environmental Microbial Technology Center of Hubei Province, School of Life Sciences, Hubei University, Wuhan, China.,National Bioenergy and Biosciences Centers, National Renewable Energy Laboratory, Golden, CO, United States
| | - Mary Ann Franden
- National Bioenergy and Biosciences Centers, National Renewable Energy Laboratory, Golden, CO, United States
| | - Xia Wang
- State Key Laboratory of Biocatalysis and Enzyme Engineering, Environmental Microbial Technology Center of Hubei Province, School of Life Sciences, Hubei University, Wuhan, China
| | - Yat-Chen Chou
- National Bioenergy and Biosciences Centers, National Renewable Energy Laboratory, Golden, CO, United States
| | - Yun Hu
- State Key Laboratory of Biocatalysis and Enzyme Engineering, Environmental Microbial Technology Center of Hubei Province, School of Life Sciences, Hubei University, Wuhan, China
| | - Steven D Brown
- Biosciences Division, Oak Ridge National Laboratory, Oak Ridge, TN, United States.,BioEnergy Science Center, Oak Ridge National Laboratory, Oak Ridge, TN, United States
| | - Philip T Pienkos
- National Bioenergy and Biosciences Centers, National Renewable Energy Laboratory, Golden, CO, United States
| | - Min Zhang
- National Bioenergy and Biosciences Centers, National Renewable Energy Laboratory, Golden, CO, United States
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16
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Physiological effects of overexpressed sigma factors on fermentative stress response of Zymomonas mobilis. Braz J Microbiol 2019; 51:65-75. [PMID: 31701383 DOI: 10.1007/s42770-019-00158-3] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/21/2019] [Accepted: 09/11/2019] [Indexed: 01/04/2023] Open
Abstract
Zymomonas mobilis is a bacterium of industrial interest due to its high ethanol productivity and high tolerance to stresses. Although the physiological parameters of fermentation are well characterized, there are few studies on the molecular mechanisms that regulate the response to fermentative stress. Z. mobilis ZM4 presents five different sigma factors identified in the genome annotation, but the absence of sigma 38 leads to the questioning of which sigma factors are responsible for its mechanism of fermentative stress response. Thus, in this study, factors sigma 32 and sigma 24, traditionally related to heat shock, were tested for their influence on the response to osmotic and ethanol stress. The overexpression of these sigma factors in Z. mobilis ZM4 strain confirmed that both are associated with heat shock response, as described in other bacteria. Moreover, sigma 32 has also a role in the adaptation to osmotic stress, increasing both growth rate and glucose influx rate. The same strain that overexpresses sigma 32 also showed a decrease in ethanol tolerance, suggesting an antagonism between these two mechanisms. It was not possible to conclude if sigma 24 really affects ethanol tolerance in Z. mobilis, but the overexpression of this sigma factor led to a decrease in ethanol productivity.
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17
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Global Analysis of Furfural-Induced Genomic Instability Using a Yeast Model. Appl Environ Microbiol 2019; 85:AEM.01237-19. [PMID: 31300396 DOI: 10.1128/aem.01237-19] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/03/2019] [Accepted: 07/01/2019] [Indexed: 02/07/2023] Open
Abstract
Furfural is an important renewable precursor for multiple commercial chemicals and fuels; a main inhibitor existing in cellulosic hydrolysate, which is used for bioethanol fermentation; and a potential carcinogen, as well. Using a genetic system in Saccharomyces cerevisiae that allows detection of crossover events, we observed that the frequency of mitotic recombination was elevated by 1.5- to 40-fold when cells were treated with 0.1 g/liter to 20 g/liter furfural. Analysis of the gene conversion tracts associated with crossover events suggested that most furfural-induced recombination resulted from repair of DNA double-strand breaks (DSBs) that occurred in the G1 phase. Furfural was incapable of breaking DNA directly in vitro but could trigger DSBs in vivo related to reactive oxygen species accumulation. By whole-genome single nucleotide polymorphism (SNP) microarray and sequencing, furfural-induced genomic alterations that range from single base substitutions, loss of heterozygosity, and chromosomal rearrangements to aneuploidy were explored. At the whole-genome level, furfural-induced events were evenly distributed across 16 chromosomes but were enriched in high-GC-content regions. Point mutations, particularly the C-to-T/G-to-A transitions, were significantly elevated in furfural-treated cells compared to wild-type cells. This study provided multiple novel insights into the global effects of furfural on genomic stability.IMPORTANCE Whether and how furfural affects genome integrity have not been clarified. Using a Saccharomyces cerevisiae model, we found that furfural exposure leads to in vivo DSBs and elevation in mitotic recombination by orders of magnitude. Gross chromosomal rearrangements and aneuploidy events also occurred at a higher frequency in furfural-treated cells. In a genome-wide analysis, we show that the patterns of mitotic recombination and point mutations differed dramatically in furfural-treated cells and wild-type cells.
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18
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Mutations in sigma 70 transcription factor improves expression of functional eukaryotic membrane proteins in Escherichia coli. Sci Rep 2019; 9:2483. [PMID: 30792443 PMCID: PMC6384906 DOI: 10.1038/s41598-019-39492-9] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2018] [Accepted: 01/09/2019] [Indexed: 12/11/2022] Open
Abstract
Eukaryotic integral membrane proteins (IMPs) are difficult to study due to low functional expression levels. To investigate factors for efficient biogenesis of eukaryotic IMPs in the prokaryotic model organism Escherichia coli, important, e.g., for isotope-labeling for NMR, we selected for E. coli cells expressing high levels of functional G protein-coupled receptors (GPCRs) by FACS. Utilizing an E. coli strain library with all non-essential genes systematically deleted, we unexpectedly discovered upon whole-genome sequencing that the improved phenotype was not conferred by the deleted genes but by various subtle alterations in the “housekeeping” sigma 70 factor (RpoD). When analyzing effects of the rpoD mutations at the transcriptome level we found that toxic effects incurred on wild-type E. coli during receptor expression were diminished by two independent and synergistic effects: a slower but longer-lasting GPCR biosynthesis and an optimized transcriptional pattern, augmenting growth and expression at low temperature, setting the basis for further bacterial strain engineering.
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19
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Zhang K, Lu X, Li Y, Jiang X, Liu L, Wang H. New technologies provide more metabolic engineering strategies for bioethanol production in Zymomonas mobilis. Appl Microbiol Biotechnol 2019; 103:2087-2099. [PMID: 30661108 DOI: 10.1007/s00253-019-09620-6] [Citation(s) in RCA: 30] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/19/2018] [Revised: 01/02/2019] [Accepted: 01/03/2019] [Indexed: 02/06/2023]
Abstract
Bioethanol has been considered as a potentially renewable energy source, and metabolic engineering plays an important role in the production of biofuels. As an efficient ethanol-producing bacterium, Zymomonas mobilis has garnered special attention due to its high sugar uptake, ethanol yield, and tolerance. Different metabolic engineering strategies have been used to establish new metabolic pathways for Z. mobilis to broaden its substrate range, remove competing pathways, and enhance its tolerance to ethanol and lignocellulosic hydrolysate inhibitors. Recent advances in omics technology, computational modeling and simulation, system biology, and synthetic biology contribute to the efficient re-design and manipulation of microbes via metabolic engineering at the whole-cell level. In this review, we summarize the progress of some new technologies used for metabolic engineering to improve bioethanol production and tolerance in Z. mobilis. Some successful examples of metabolic engineering used to develop strains for ethanol production are described in detail. Lastly, some important strategies for future metabolic engineering efforts are also highlighted.
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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, Henan, China
| | - Xinxin Lu
- Henan Province Engineering Laboratory for Bioconversion Technology of Functional Microbes, College of Life Sciences, Henan Normal University, Xinxiang, 453007, Henan, China
| | - Yi Li
- Henan Province Engineering Laboratory for Bioconversion Technology of Functional Microbes, College of Life Sciences, Henan Normal University, Xinxiang, 453007, Henan, China
| | - Xiaobing Jiang
- Henan Province Engineering Laboratory for Bioconversion Technology of Functional Microbes, College of Life Sciences, Henan Normal University, Xinxiang, 453007, Henan, China
| | - Lei Liu
- Henan Province Engineering Laboratory for Bioconversion Technology of Functional Microbes, College of Life Sciences, Henan Normal University, Xinxiang, 453007, Henan, China
| | - Hailei Wang
- Henan Province Engineering Laboratory for Bioconversion Technology of Functional Microbes, College of Life Sciences, Henan Normal University, Xinxiang, 453007, Henan, China.
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20
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Wang W, Wu B, Qin H, Liu P, Qin Y, Duan G, Hu G, He M. Genome shuffling enhances stress tolerance of Zymomonas mobilis to two inhibitors. BIOTECHNOLOGY FOR BIOFUELS 2019; 12:288. [PMID: 31890016 PMCID: PMC6913010 DOI: 10.1186/s13068-019-1631-4] [Citation(s) in RCA: 22] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/12/2019] [Accepted: 12/05/2019] [Indexed: 05/19/2023]
Abstract
BACKGROUND Furfural and acetic acid are the two major inhibitors generated during lignocellulose pretreatment and hydrolysis, would severely inhibit the cell growth, metabolism, and ethanol fermentation efficiency of Zymomonas mobilis. Effective genome shuffling mediated by protoplast electrofusion was developed and then applied to Z. mobilis. RESULTS After two rounds of genome shuffling, 10 different mutants with improved cell growth and ethanol yield in the presence of 5.0 g/L acetic acid and 3.0 g/L furfural were obtained. The two most prominent genome-shuffled strains, 532 and 533, were further investigated along with parental strains in the presence of 7.0 g/L acetic acid and 3.0 g/L furfural. The results showed that mutants 532 and 533 were superior to the parental strain AQ8-1 in the presence of 7.0 g/L acetic acid, with a shorter fermentation time (30 h) and higher productivity than AQ8-1. Mutant 533 exhibited subtle differences from parental strain F34 in the presence of 3.0 g/L furfural. Mutations present in 10 genome-shuffled strains were identified via whole-genome resequencing, and the source of each mutation was identified as either de novo mutation or recombination of the parent genes. CONCLUSIONS These results indicate that genome shuffling is an efficient method for enhancing stress tolerance in Z. mobilis. The engineered strains generated in this study could be potential cellulosic ethanol producers in the future.
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Affiliation(s)
- Weiting Wang
- Biomass Energy Technology Research Centre, Key Laboratory of Development and Application of Rural Renewable Energy (Ministry of Agriculture and Rural Affairs), Biogas Institute of Ministry of Agriculture and Rural Affairs, Section 4-13, Renmin Rd. South, Chengdu, 610041 People’s Republic of China
- Graduate School of Chinese Academy of Agricultural Science, Beijing, 100081 People’s Republic of China
| | - Bo Wu
- Biomass Energy Technology Research Centre, Key Laboratory of Development and Application of Rural Renewable Energy (Ministry of Agriculture and Rural Affairs), Biogas Institute of Ministry of Agriculture and Rural Affairs, Section 4-13, Renmin Rd. South, Chengdu, 610041 People’s Republic of China
| | - Han Qin
- Biomass Energy Technology Research Centre, Key Laboratory of Development and Application of Rural Renewable Energy (Ministry of Agriculture and Rural Affairs), Biogas Institute of Ministry of Agriculture and Rural Affairs, Section 4-13, Renmin Rd. South, Chengdu, 610041 People’s Republic of China
| | - Panting Liu
- Biomass Energy Technology Research Centre, Key Laboratory of Development and Application of Rural Renewable Energy (Ministry of Agriculture and Rural Affairs), Biogas Institute of Ministry of Agriculture and Rural Affairs, Section 4-13, Renmin Rd. South, Chengdu, 610041 People’s Republic of China
- Graduate School of Chinese Academy of Agricultural Science, Beijing, 100081 People’s Republic of China
| | - Yao Qin
- Biomass Energy Technology Research Centre, Key Laboratory of Development and Application of Rural Renewable Energy (Ministry of Agriculture and Rural Affairs), Biogas Institute of Ministry of Agriculture and Rural Affairs, Section 4-13, Renmin Rd. South, Chengdu, 610041 People’s Republic of China
- College of Pharmacy and Biological Engineering, Chengdu University, Chengdu, 610041 People’s Republic of China
| | - Guowei Duan
- Biomass Energy Technology Research Centre, Key Laboratory of Development and Application of Rural Renewable Energy (Ministry of Agriculture and Rural Affairs), Biogas Institute of Ministry of Agriculture and Rural Affairs, Section 4-13, Renmin Rd. South, Chengdu, 610041 People’s Republic of China
- Graduate School of Chinese Academy of Agricultural Science, Beijing, 100081 People’s Republic of China
| | - Guoquan Hu
- Biomass Energy Technology Research Centre, Key Laboratory of Development and Application of Rural Renewable Energy (Ministry of Agriculture and Rural Affairs), Biogas Institute of Ministry of Agriculture and Rural Affairs, Section 4-13, Renmin Rd. South, Chengdu, 610041 People’s Republic of China
- Graduate School of Chinese Academy of Agricultural Science, Beijing, 100081 People’s Republic of China
| | - Mingxiong He
- Biomass Energy Technology Research Centre, Key Laboratory of Development and Application of Rural Renewable Energy (Ministry of Agriculture and Rural Affairs), Biogas Institute of Ministry of Agriculture and Rural Affairs, Section 4-13, Renmin Rd. South, Chengdu, 610041 People’s Republic of China
- Graduate School of Chinese Academy of Agricultural Science, Beijing, 100081 People’s Republic of China
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21
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Wang X, He Q, Yang Y, Wang J, Haning K, Hu Y, Wu B, He M, Zhang Y, Bao J, Contreras LM, Yang S. Advances and prospects in metabolic engineering of Zymomonas mobilis. Metab Eng 2018; 50:57-73. [PMID: 29627506 DOI: 10.1016/j.ymben.2018.04.001] [Citation(s) in RCA: 76] [Impact Index Per Article: 12.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/25/2018] [Revised: 03/31/2018] [Accepted: 04/01/2018] [Indexed: 12/22/2022]
Abstract
Biorefinery of biomass-based biofuels and biochemicals by microorganisms is a competitive alternative of traditional petroleum refineries. Zymomonas mobilis is a natural ethanologen with many desirable characteristics, which makes it an ideal industrial microbial biocatalyst for commercial production of desirable bioproducts through metabolic engineering. In this review, we summarize the metabolic engineering progress achieved in Z. mobilis to expand its substrate and product ranges as well as to enhance its robustness against stressful conditions such as inhibitory compounds within the lignocellulosic hydrolysates and slurries. We also discuss a few metabolic engineering strategies that can be applied in Z. mobilis to further develop it as a robust workhorse for economic lignocellulosic bioproducts. In addition, we briefly review the progress of metabolic engineering in Z. mobilis related to the classical synthetic biology cycle of "Design-Build-Test-Learn", as well as the progress and potential to develop Z. mobilis as a model chassis for biorefinery practices in the synthetic biology era.
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Affiliation(s)
- Xia Wang
- Hubei Collaborative Innovation Center for Green Transformation of Bio-resources, Environmental Microbial Technology Center of Hubei Province, Hubei Key Laboratory of Industrial Biotechnology, College of Life Sciences, Hubei University, Wuhan 430062, China.
| | - Qiaoning He
- Hubei Collaborative Innovation Center for Green Transformation of Bio-resources, Environmental Microbial Technology Center of Hubei Province, Hubei Key Laboratory of Industrial Biotechnology, College of Life Sciences, Hubei University, Wuhan 430062, China.
| | - Yongfu Yang
- Hubei Collaborative Innovation Center for Green Transformation of Bio-resources, Environmental Microbial Technology Center of Hubei Province, Hubei Key Laboratory of Industrial Biotechnology, College of Life Sciences, Hubei University, Wuhan 430062, China.
| | - Jingwen Wang
- Hubei Collaborative Innovation Center for Green Transformation of Bio-resources, Environmental Microbial Technology Center of Hubei Province, Hubei Key Laboratory of Industrial Biotechnology, College of Life Sciences, Hubei University, Wuhan 430062, China.
| | - Katie Haning
- Institute for Cellular and Molecular Biology, Department of Chemical Engineering, Cockrell School of Engineering, University of Texas at Austin, Austin, TX, United States.
| | - Yun Hu
- Hubei Collaborative Innovation Center for Green Transformation of Bio-resources, Environmental Microbial Technology Center of Hubei Province, Hubei Key Laboratory of Industrial Biotechnology, College of Life Sciences, Hubei University, Wuhan 430062, China.
| | - Bo Wu
- Key Laboratory of Development and Application of Rural Renewable Energy, Biomass Energy Technology Research Centre, Biogas Institute of Ministry of Agriculture, South Renmin Road, Chengdu 610041, China.
| | - Mingxiong He
- Key Laboratory of Development and Application of Rural Renewable Energy, Biomass Energy Technology Research Centre, Biogas Institute of Ministry of Agriculture, South Renmin Road, Chengdu 610041, China.
| | - Yaoping Zhang
- DOE-Great Lakes Bioenergy Research Center (GLBRC), University of Wisconsin-Madison, Madison, WI, United States.
| | - Jie Bao
- State Key Laboratory of Bioreactor Engineering, East China University of Science and Technology, 130 Meilong Road, Shanghai 200237, China.
| | - Lydia M Contreras
- Institute for Cellular and Molecular Biology, Department of Chemical Engineering, Cockrell School of Engineering, University of Texas at Austin, Austin, TX, United States.
| | - Shihui Yang
- Hubei Collaborative Innovation Center for Green Transformation of Bio-resources, Environmental Microbial Technology Center of Hubei Province, Hubei Key Laboratory of Industrial Biotechnology, College of Life Sciences, Hubei University, Wuhan 430062, China.
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22
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Yang S, Franden MA, Yang Q, Chou YC, Zhang M, Pienkos PT. Identification of Inhibitors in Lignocellulosic Slurries and Determination of Their Effect on Hydrocarbon-Producing Microorganisms. Front Bioeng Biotechnol 2018; 6:23. [PMID: 29670877 PMCID: PMC5894158 DOI: 10.3389/fbioe.2018.00023] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/18/2017] [Accepted: 02/22/2018] [Indexed: 11/24/2022] Open
Abstract
The aim of this work was to identify inhibitors in pretreated lignocellulosic slurries, evaluate high-throughput screening strategies, and investigate the impact of inhibitors on potential hydrocarbon-producing microorganisms. Compounds present in slurries that could inhibit microbial growth were identified through a detailed analysis of saccharified slurries by applying a combination of approaches of high-performance liquid chromatography, GC-MS, LC-DAD-MS, and ICP-MS. Several high-throughput assays were then evaluated to generate toxicity profiles. Our results demonstrated that Bioscreen C was useful for analyzing bacterial toxicity but not for yeast. AlamarBlue reduction assay can be a useful high-throughput assay for both bacterial and yeast strains as long as medium components do not interfere with fluorescence measurements. In addition, this work identified two major inhibitors (furfural and ammonium acetate) for three potential hydrocarbon-producing bacterial species that include Escherichia coli, Cupriavidus necator, and Rhodococcus opacus PD630, which are also the primary inhibitors for ethanologens. This study was strived to establish a pipeline to quantify inhibitory compounds in biomass slurries and high-throughput approaches to investigate the effect of inhibitors on microbial biocatalysts, which can be applied for various biomass slurries or hydrolyzates generated through different pretreatment and enzymatic hydrolysis processes or different microbial candidates.
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Affiliation(s)
- Shihui Yang
- Hubei Collaborative Innovation Center for Green Transformation of Bio-Resources, Environmental Microbial Technology Center of Hubei Province, Hubei Key Laboratory of Industrial Biotechnology, College of Life Sciences, Hubei University, Wuhan, China
- National Bioenergy Center, National Renewable Energy Laboratory, Golden, CO, United States
| | - Mary Ann Franden
- National Bioenergy Center, National Renewable Energy Laboratory, Golden, CO, United States
| | - Qing Yang
- Hubei Collaborative Innovation Center for Green Transformation of Bio-Resources, Environmental Microbial Technology Center of Hubei Province, Hubei Key Laboratory of Industrial Biotechnology, College of Life Sciences, Hubei University, Wuhan, China
| | - Yat-Chen Chou
- National Bioenergy Center, National Renewable Energy Laboratory, Golden, CO, United States
| | - Min Zhang
- National Bioenergy Center, National Renewable Energy Laboratory, Golden, CO, United States
| | - Philip T. Pienkos
- National Bioenergy Center, National Renewable Energy Laboratory, Golden, CO, United States
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23
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Huang S, Xue T, Wang Z, Ma Y, He X, Hong J, Zou S, Song H, Zhang M. Furfural-tolerant Zymomonas mobilis derived from error-prone PCR-based whole genome shuffling and their tolerant mechanism. Appl Microbiol Biotechnol 2018; 102:3337-3347. [PMID: 29464326 DOI: 10.1007/s00253-018-8817-8] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/02/2017] [Revised: 01/22/2018] [Accepted: 01/27/2018] [Indexed: 11/29/2022]
Abstract
Furfural-tolerant strain is essential for the fermentative production of biofuels or chemicals from lignocellulosic biomass. In this study, Zymomonas mobilis CP4 was for the first time subjected to error-prone PCR-based whole genome shuffling, and the resulting mutants F211 and F27 that could tolerate 3 g/L furfural were obtained. The mutant F211 under various furfural stress conditions could rapidly grow when the furfural concentration reduced to 1 g/L. Meanwhile, the two mutants also showed higher tolerance to high concentration of glucose than the control strain CP4. Genome resequencing revealed that the F211 and F27 had 12 and 13 single-nucleotide polymorphisms. The activity assay demonstrated that the activity of NADH-dependent furfural reductase in mutant F211 and CP4 was all increased under furfural stress, and the activity peaked earlier in mutant than in control. Also, furfural level in the culture of F211 was also more rapidly decreased. These indicate that the increase in furfural tolerance of the mutants may be resulted from the enhanced NADH-dependent furfural reductase activity during early log phase, which could lead to an accelerated furfural detoxification process in mutants. In all, we obtained Z. mobilis mutants with enhanced furfural and high concentration of glucose tolerance, and provided valuable clues for the mechanism of furfural tolerance and strain development.
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Affiliation(s)
- Suzhen Huang
- R&D Center for Petrochemical Technology, Tianjin University, Weijin Road No. 92, Nankai District, Tianjin, 300072, China.,Department of Biochemical Engineering, School of Chemical Engineering and Technology, Tianjin University, Tianjin, 300072, China
| | - Tingli Xue
- R&D Center for Petrochemical Technology, Tianjin University, Weijin Road No. 92, Nankai District, Tianjin, 300072, China.,Department of Biochemical Engineering, School of Chemical Engineering and Technology, Tianjin University, Tianjin, 300072, China
| | - Zhiquan Wang
- R&D Center for Petrochemical Technology, Tianjin University, Weijin Road No. 92, Nankai District, Tianjin, 300072, China.,Department of Biochemical Engineering, School of Chemical Engineering and Technology, Tianjin University, Tianjin, 300072, China
| | - Yuanyuan Ma
- R&D Center for Petrochemical Technology, Tianjin University, Weijin Road No. 92, Nankai District, Tianjin, 300072, China. .,Collaborative Innovation Centre of Chemical Science and Engineering (Tianjin), School of Chemical Engineering and Technology, Tianjin, China.
| | - Xueting He
- R&D Center for Petrochemical Technology, Tianjin University, Weijin Road No. 92, Nankai District, Tianjin, 300072, China.,Department of Biochemical Engineering, School of Chemical Engineering and Technology, Tianjin University, Tianjin, 300072, China
| | - Jiefang Hong
- R&D Center for Petrochemical Technology, Tianjin University, Weijin Road No. 92, Nankai District, Tianjin, 300072, China
| | - Shaolan Zou
- R&D Center for Petrochemical Technology, Tianjin University, Weijin Road No. 92, Nankai District, Tianjin, 300072, China
| | - Hao Song
- Collaborative Innovation Centre of Chemical Science and Engineering (Tianjin), School of Chemical Engineering and Technology, Tianjin, China. .,Key Laboratory of Systems Bioengineering (Ministry of Education), School of Chemical Engineering and Technology, Tianjin University, Tianjin, China.
| | - Minhua Zhang
- R&D Center for Petrochemical Technology, Tianjin University, Weijin Road No. 92, Nankai District, Tianjin, 300072, China.,Collaborative Innovation Centre of Chemical Science and Engineering (Tianjin), School of Chemical Engineering and Technology, Tianjin, China
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24
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Yang Y, Hu M, Tang Y, Geng B, Qiu M, He Q, Chen S, Wang X, Yang S. Progress and perspective on lignocellulosic hydrolysate inhibitor tolerance improvement in Zymomonas mobilis. BIORESOUR BIOPROCESS 2018. [DOI: 10.1186/s40643-018-0193-9] [Citation(s) in RCA: 26] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022] Open
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25
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Liu YF, Hsieh CW, Chang YS, Wung BS. Effect of acetic acid on ethanol production by Zymomonas mobilis mutant strains through continuous adaptation. BMC Biotechnol 2017; 17:63. [PMID: 28764759 PMCID: PMC5540488 DOI: 10.1186/s12896-017-0385-y] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/11/2017] [Accepted: 07/25/2017] [Indexed: 02/03/2023] Open
Abstract
Background Acetic acid is a predominant by-product of lignocellulosic biofuel process, which inhibits microbial biocatalysts. Development of bacterial strains that are tolerant to acetic acid is challenging due to poor understanding of the underlying molecular mechanisms. Results In this study, we generated and characterized two acetic acid-tolerant strains of Zymomonas mobilis using N-methyl-N′-nitro-N-nitrosoguanidine (NTG)-acetate adaptive breeding. Two mutants, ZMA-142 and ZMA-167, were obtained, showing a significant growth rate at a concentration of 244 mM sodium acetate, while the growth of Z. mobilis ATCC 31823 were completely inhibited in presence of 195 mM sodium acetate. Our data showed that acetate-tolerance of ZMA-167 was attributed to a co-transcription of nhaA from ZMO0117, whereas the co-transcription was absent in ATCC 31823 and ZMA-142. Moreover, ZMA-142 and ZMA-167 exhibited a converstion rate (practical ethanol yield to theorical ethanol yield) of 90.16% and 86% at 195 mM acetate-pH 5 stress condition, respectively. We showed that acid adaptation of ZMA-142 and ZMA-167 to 146 mM acetate increased ZMA-142 and ZMA-167 resulted in an increase in ethanol yield by 32.21% and 21.16% under 195 mM acetate-pH 5 stress condition, respectively. Conclusion The results indicate the acetate-adaptive seed culture of acetate-tolerant strains, ZMA-142 and ZMA-167, could enhance the ethanol production during fermentation.
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Affiliation(s)
- Yu-Fan Liu
- Division of Allergy, Department of Pediatrics, Chung-Shan Medical University Hospital, Taichung, Taiwan.,Department of Biomedical Sciences, College of Medicine Sciences and Technology, Chung Shan Medical University, Taichung, Taiwan
| | - Chia-Wen Hsieh
- Department of Microbiology, Immunology and Biopharmaceuticals, National Chiayi University, Chiayi, Taiwan.
| | - Yao-Sheng Chang
- Department of Microbiology, Immunology and Biopharmaceuticals, National Chiayi University, Chiayi, Taiwan
| | - Being-Sun Wung
- Department of Microbiology, Immunology and Biopharmaceuticals, National Chiayi University, Chiayi, Taiwan
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26
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Qiu Z, Jiang R. Improving Saccharomyces cerevisiae ethanol production and tolerance via RNA polymerase II subunit Rpb7. BIOTECHNOLOGY FOR BIOFUELS 2017; 10:125. [PMID: 28515784 PMCID: PMC5433082 DOI: 10.1186/s13068-017-0806-0] [Citation(s) in RCA: 33] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/11/2016] [Accepted: 04/27/2017] [Indexed: 05/31/2023]
Abstract
BACKGROUND Classical strain engineering methods often have limitations in altering multigenetic cellular phenotypes. Here we try to improve Saccharomyces cerevisiae ethanol tolerance and productivity by reprogramming its transcription profile through rewiring its key transcription component RNA polymerase II (RNAP II), which plays a central role in synthesizing mRNAs. This is the first report on using directed evolution method to engineer RNAP II to alter S. cerevisiae strain phenotypes. RESULTS Error-prone PCR was employed to engineer the subunit Rpb7 of RNAP II to improve yeast ethanol tolerance and production. Based on previous studies and the presumption that improved ethanol resistance would lead to enhanced ethanol production, we first isolated variant M1 with much improved resistance towards 8 and 10% ethanol. The ethanol titers of M1 was ~122 g/L (96.58% of the theoretical yield) under laboratory very high gravity (VHG) fermentation, 40% increase as compared to the control. DNA microarray assay showed that 369 genes had differential expression in M1 after 12 h VHG fermentation, which are involved in glycolysis, alcoholic fermentation, oxidative stress response, etc. CONCLUSIONS This is the first study to demonstrate the possibility of engineering eukaryotic RNAP to alter global transcription profile and improve strain phenotypes. Targeting subunit Rpb7 of RNAP II was able to bring differential expression in hundreds of genes in S. cerevisiae, which finally led to improvement in yeast ethanol tolerance and production.
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Affiliation(s)
- Zilong Qiu
- School of Chemical and Biomedical Engineering, Nanyang Technological University, 62 Nanyang Drive, Singapore, 637459 Singapore
| | - Rongrong Jiang
- School of Chemical and Biomedical Engineering, Nanyang Technological University, 62 Nanyang Drive, Singapore, 637459 Singapore
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27
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Wang X, Gao Q, Bao J. Enhancement of furan aldehydes conversion in Zymomonas mobilis by elevating dehydrogenase activity and cofactor regeneration. BIOTECHNOLOGY FOR BIOFUELS 2017; 10:24. [PMID: 28163781 PMCID: PMC5282692 DOI: 10.1186/s13068-017-0714-3] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/12/2016] [Accepted: 01/18/2017] [Indexed: 05/15/2023]
Abstract
BACKGROUND Furfural and 5-hydroxymethylfurfural (HMF) are the two major furan aldehyde inhibitors generated from lignocellulose dilute acid pretreatment which significantly inhibit subsequent microbial cell growth and ethanol fermentation. Zymomonas mobilis is an important strain for cellulosic ethanol fermentation but can be severely inhibited by furfural and (or) HMF. Previous study showed that Z. mobilis contains its native oxidoreductases to catalyze the conversion of furfural and HMF, but the corresponding genes have not been identified. RESULTS This study identified a NADPH-dependent alcohol dehydrogenase gene ZMO1771 from Z. mobilis ZM4, which is responsible for the efficient reduction of furfural and HMF. Over-expression of ZMO1771 in Z. mobilis significantly increased the conversion rate to both furfural and HMF and resulted in an accelerated cell growth and improved ethanol productivity in corn stover hydrolysate. Further, the ethanol fermentation performance was enhanced again by co-expression of the transhydrogenase gene udhA with ZMO1771 by elevating the NADPH availability. CONCLUSIONS A genetically modified Z. mobilis by co-expressing alcohol dehydrogenase gene ZMO1771 with transhydrogenase gene udhA showed enhanced conversion rate of furfural and HMF and accelerated ethanol fermentability from lignocellulosic hydrolysate. The results presented in this study provide an important method on constructing robust strains for efficient ethanol fermentation from lignocellulose feedstock.
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Affiliation(s)
- Xia Wang
- State Key Laboratory of Bioreactor Engineering, East China University of Science and Technology, 130 Meilong Road, Shanghai, 200237 China
| | - Qiuqiang Gao
- State Key Laboratory of Bioreactor Engineering, East China University of Science and Technology, 130 Meilong Road, Shanghai, 200237 China
| | - Jie Bao
- State Key Laboratory of Bioreactor Engineering, East China University of Science and Technology, 130 Meilong Road, Shanghai, 200237 China
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28
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Yang S, Fei Q, Zhang Y, Contreras LM, Utturkar SM, Brown SD, Himmel ME, Zhang M. Zymomonas mobilis as a model system for production of biofuels and biochemicals. Microb Biotechnol 2016; 9:699-717. [PMID: 27629544 PMCID: PMC5072187 DOI: 10.1111/1751-7915.12408] [Citation(s) in RCA: 97] [Impact Index Per Article: 12.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/17/2016] [Revised: 08/03/2016] [Accepted: 08/05/2016] [Indexed: 12/04/2022] Open
Abstract
Zymomonas mobilis is a natural ethanologen with many desirable industrial biocatalyst characteristics. In this review, we will discuss work to develop Z. mobilis as a model system for biofuel production from the perspectives of substrate utilization, development for industrial robustness, potential product spectrum, strain evaluation and fermentation strategies. This review also encompasses perspectives related to classical genetic tools and emerging technologies in this context.
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Affiliation(s)
- Shihui Yang
- National Bioenergy Center, National Renewable Energy Laboratory, Golden, CO, 80401, USA. .,Hubei Collaborative Innovation Center for Green Transformation of Bio-resources, Hubei Key Laboratory of Industrial Biotechnology, College of Life Sciences, Hubei University, Wuhan, 430062, China.
| | - Qiang Fei
- National Bioenergy Center, National Renewable Energy Laboratory, Golden, CO, 80401, USA.,School of Chemical Engineering and Technology, Xi'an Jiaotong University, Xi'an, 710049, China
| | - Yaoping Zhang
- Great Lakes Bioenergy Research Center, Wisconsin Energy Institute, University of Wisconsin, Madison, WI, 53726, USA
| | - Lydia M Contreras
- McKetta Department of Chemical Engineering, University of Texas, Austin, TX, 78712, USA
| | - Sagar M Utturkar
- Graduate School of Genome Science and Technology, University of Tennessee, Knoxville, TN, 37919, USA
| | - Steven D Brown
- Graduate School of Genome Science and Technology, University of Tennessee, Knoxville, TN, 37919, USA.,BioEnergy Science Center, Oak Ridge National Laboratory, Oak Ridge, TN, 37831, USA.,Biosciences Division, Oak Ridge National Laboratory, Oak Ridge, TN, 37831, USA
| | - Michael E Himmel
- Biosciences 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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29
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Wang JL, Wu B, Qin H, You Y, Liu S, Shui ZX, Tan FR, Wang YW, Zhu QL, Li YB, Ruan ZY, Ma KD, Dai LC, Hu GQ, He MX. Engineered Zymomonas mobilis for salt tolerance using EZ-Tn5-based transposon insertion mutagenesis system. Microb Cell Fact 2016; 15:101. [PMID: 27287016 PMCID: PMC4901475 DOI: 10.1186/s12934-016-0503-x] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/21/2016] [Accepted: 06/01/2016] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND The cell growth and ethanol yield of Zymomonas mobilis may be detrimentally affected by salt stress frequently present in some biomass-based fermentation systems, leading to a decrease in the rate of sugar conversion to ethanol or other bioproducts. To address this problem, improving the salt tolerance of Z. mobilis is a desirable way. However, limited progress has been made in development of Z. mobilis with higher salt tolerance for some technical challenges in the past decades. Recently, transposon insertion mutant system has been widely used as a novel genetic tool in many organisms to develop mutant strains. In this study, Tn5-based transposon insertion mutagenesis system firstly used for construction of higher salt tolerance strain in Z. mobilis. RESULTS Approximately 200 Z. mobilis ZM4 mutants were generated by using Tn5-based transposon mutagenesis system. The mutant strain ZMT2 with improved salt tolerance phenotype was obtained by screening on RM agar plates with additional 1 % NaCl. Strain ZMT2 was confirmed to exhibit better fermentation performance under NaCl stress than wild type of strain ZM4. The transposon insertion was located in ZMO1122 (himA) by genome walking. Discruption of himA gene showed that himA may play an important role in response to salt tolerance in Z. mobils. CONCLUSIONS The mutant strain ZMT2 with a transposon insertion in himA gene of the genome showed obviously higher sugar conversion rate to ethonal under up to 2 % NaCl stress than did the wild ZM4 strain. Besides, ZMT2 exhibited shared fermentative capabilities with wild ZM4 strain under no or low NaCl stress. This report firstly showed that himA played a role in responding to NaCl stress. Furthermore, the result indicated that Tn5-based transposon mutagenesis system was a feasible tool not only for genetic engineering in Z. mobilis strain improvement, but also in tapping resistent genes.
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Affiliation(s)
- Jing-Li Wang
- Key Laboratory of Development and Application of Rural Renewable Energy (Ministry of Agriculture), Biomass Energy Technology Research Centre, Biogas Institute of Ministry of Agriculture, Section 4-13, Renmin Nanlu, Chengdu, 610041, People's Republic of China
| | - Bo Wu
- Key Laboratory of Development and Application of Rural Renewable Energy (Ministry of Agriculture), Biomass Energy Technology Research Centre, Biogas Institute of Ministry of Agriculture, Section 4-13, Renmin Nanlu, Chengdu, 610041, People's Republic of China
| | - Han Qin
- Key Laboratory of Development and Application of Rural Renewable Energy (Ministry of Agriculture), Biomass Energy Technology Research Centre, Biogas Institute of Ministry of Agriculture, Section 4-13, Renmin Nanlu, Chengdu, 610041, People's Republic of China
| | - Yang You
- Key Laboratory of Development and Application of Rural Renewable Energy (Ministry of Agriculture), Biomass Energy Technology Research Centre, Biogas Institute of Ministry of Agriculture, Section 4-13, Renmin Nanlu, Chengdu, 610041, People's Republic of China
| | - Song Liu
- Key Laboratory of Development and Application of Rural Renewable Energy (Ministry of Agriculture), Biomass Energy Technology Research Centre, Biogas Institute of Ministry of Agriculture, Section 4-13, Renmin Nanlu, Chengdu, 610041, People's Republic of China
| | - Zong-Xia Shui
- Key Laboratory of Development and Application of Rural Renewable Energy (Ministry of Agriculture), Biomass Energy Technology Research Centre, Biogas Institute of Ministry of Agriculture, Section 4-13, Renmin Nanlu, Chengdu, 610041, People's Republic of China
| | - Fu-Rong Tan
- Key Laboratory of Development and Application of Rural Renewable Energy (Ministry of Agriculture), Biomass Energy Technology Research Centre, Biogas Institute of Ministry of Agriculture, Section 4-13, Renmin Nanlu, Chengdu, 610041, People's Republic of China
| | - Yan-Wei Wang
- Key Laboratory of Development and Application of Rural Renewable Energy (Ministry of Agriculture), Biomass Energy Technology Research Centre, Biogas Institute of Ministry of Agriculture, Section 4-13, Renmin Nanlu, Chengdu, 610041, People's Republic of China
| | - Qi-Li Zhu
- Key Laboratory of Development and Application of Rural Renewable Energy (Ministry of Agriculture), Biomass Energy Technology Research Centre, Biogas Institute of Ministry of Agriculture, Section 4-13, Renmin Nanlu, Chengdu, 610041, People's Republic of China
| | - Yan-Bin Li
- Xinjiang Production and Construction Corps Key Laboratory of Protection and Utilization of Biological Resources, College of Life Sciences, Tarim University, Tarim Basin, Alaer City, 843300, People's Republic of China
| | - Zhi-Yong Ruan
- Key Laboratory of Microbial Resources (Ministry of Agriculture, China), Institute of Agricultural Resources and Regional Planning, CAAS, Beijing, 100081, People's Republic of China
| | - Ke-Dong Ma
- College of Environmental and Chemical Engineering, Dalian University, Dalian, 116622, People's Republic of China
| | - Li-Chun Dai
- Key Laboratory of Development and Application of Rural Renewable Energy (Ministry of Agriculture), Biomass Energy Technology Research Centre, Biogas Institute of Ministry of Agriculture, Section 4-13, Renmin Nanlu, Chengdu, 610041, People's Republic of China
| | - Guo-Quan Hu
- Key Laboratory of Development and Application of Rural Renewable Energy (Ministry of Agriculture), Biomass Energy Technology Research Centre, Biogas Institute of Ministry of Agriculture, Section 4-13, Renmin Nanlu, Chengdu, 610041, People's Republic of China
| | - Ming-Xiong He
- Key Laboratory of Development and Application of Rural Renewable Energy (Ministry of Agriculture), Biomass Energy Technology Research Centre, Biogas Institute of Ministry of Agriculture, Section 4-13, Renmin Nanlu, Chengdu, 610041, People's Republic of China.
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30
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Branduardi P. Synthetic Biology for Cellular Remodelling to Elicit Industrially Relevant Microbial Phenotypes. Synth Biol (Oxf) 2016. [DOI: 10.1007/978-3-319-22708-5_5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022] Open
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31
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Yang S, Mohagheghi A, Franden MA, Chou YC, Chen X, Dowe N, Himmel ME, Zhang M. Metabolic engineering of Zymomonas mobilis for 2,3-butanediol production from lignocellulosic biomass sugars. BIOTECHNOLOGY FOR BIOFUELS 2016; 9:189. [PMID: 27594916 PMCID: PMC5010730 DOI: 10.1186/s13068-016-0606-y] [Citation(s) in RCA: 56] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/07/2016] [Accepted: 08/26/2016] [Indexed: 05/18/2023]
Abstract
BACKGROUND To develop pathways for advanced biofuel production, and to understand the impact of host metabolism and environmental conditions on heterologous pathway engineering for economic advanced biofuels production from biomass, we seek to redirect the carbon flow of the model ethanologen Zymomonas mobilis to produce desirable hydrocarbon intermediate 2,3-butanediol (2,3-BDO). 2,3-BDO is a bulk chemical building block, and can be upgraded in high yields to gasoline, diesel, and jet fuel. RESULTS 2,3-BDO biosynthesis pathways from various bacterial species were examined, which include three genes encoding acetolactate synthase, acetolactate decarboxylase, and butanediol dehydrogenase. Bioinformatics analysis was carried out to pinpoint potential bottlenecks for high 2,3-BDO production. Different combinations of 2,3-BDO biosynthesis metabolic pathways using genes from different bacterial species have been constructed. Our results demonstrated that carbon flux can be deviated from ethanol production into 2,3-BDO biosynthesis, and all three heterologous genes are essential to efficiently redirect pyruvate from ethanol production for high 2,3-BDO production in Z. mobilis. The down-selection of best gene combinations up to now enabled Z. mobilis to reach the 2,3-BDO production of more than 10 g/L from glucose and xylose, as well as mixed C6/C5 sugar streams derived from the deacetylation and mechanical refining process. CONCLUSIONS This study confirms the value of integrating bioinformatics analysis and systems biology data during metabolic engineering endeavors, provides guidance for value-added chemical production in Z. mobilis, and reveals the interactions between host metabolism, oxygen levels, and a heterologous 2,3-BDO biosynthesis pathway. Taken together, this work provides guidance for future metabolic engineering efforts aimed at boosting 2,3-BDO titer anaerobically.
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Affiliation(s)
- Shihui Yang
- National Bioenergy Center, National Renewable Energy Laboratory, Golden, 80401 USA
- Hubei Collaborative Innovation Center for Green Transformation of Bio-resources, Hubei Key Laboratory of Industrial Biotechnology, College of Life Sciences, Hubei University, Wuhan, 430062 China
| | - Ali Mohagheghi
- National Bioenergy Center, National Renewable Energy Laboratory, Golden, 80401 USA
| | - Mary Ann Franden
- National Bioenergy Center, National Renewable Energy Laboratory, Golden, 80401 USA
| | - Yat-Chen Chou
- National Bioenergy Center, National Renewable Energy Laboratory, Golden, 80401 USA
| | - Xiaowen Chen
- National Bioenergy Center, National Renewable Energy Laboratory, Golden, 80401 USA
| | - Nancy Dowe
- National Bioenergy Center, National Renewable Energy Laboratory, Golden, 80401 USA
| | - Michael E. Himmel
- Biosciences Center, National Renewable Energy Laboratory, Golden, CO 80401 USA
| | - Min Zhang
- National Bioenergy Center, National Renewable Energy Laboratory, Golden, 80401 USA
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