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Peng Q, Bao W, Geng B, Yang S. Biosensor-assisted CRISPRi high-throughput screening to identify genetic targets in Zymomonas mobilis for high d-lactate production. Synth Syst Biotechnol 2024; 9:242-249. [PMID: 38390372 PMCID: PMC10883783 DOI: 10.1016/j.synbio.2024.02.002] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/28/2023] [Revised: 02/04/2024] [Accepted: 02/04/2024] [Indexed: 02/24/2024] Open
Abstract
Lactate is an important monomer for the synthesis of poly-lactate (PLA), which is a substitute for the petrochemical plastics. To achieve the goal of high lactate titer, rate, and yield for commercial production, efficient lactate production pathway is needed as well as genetic targets that affect high lactate production and tolerance. In this study, an LldR-based d-lactate biosensor with a broad dynamic range was first applied into Zymomonas mobilis to select mutant strains with strong GFP fluorescence, which could be the mutant strains with increased d-lactate production. Then, LldR-based d-lactate biosensor was combined with a genome-wide CRISPR interference (CRISPRi) library targeting the entire genome to generate thousands of mutants with gRNA targeting different genetic targets across the whole genome. Specifically, two mutant libraries were selected containing 105 and 104 mutants with different interference sites from two rounds of fluorescence-activated cell sorting (FACS), respectively. Two genetic targets of ZMO1323 and ZMO1530 were characterized and confirmed to be associated with the increased d-lactate production, further knockout of ZMO1323 and ZMO1530 resulted in a 15% and 21% increase of d-lactate production, respectively. This work thus not only established a high-throughput approach that combines genome-scale CRISPRi and biosensor-assisted screening to identify genetic targets associated with d-lactate production in Z. mobilis, but also provided a feasible high-throughput screening approach for rapid identification of genetic targets associated with strain performance for other industrial microorganisms.
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Affiliation(s)
- Qiqun Peng
- State Key Laboratory of Biocatalysis and Enzyme Engineering, and School of Life Sciences, Hubei University, Wuhan, 430062, China
| | - Weiwei Bao
- State Key Laboratory of Biocatalysis and Enzyme Engineering, and School of Life Sciences, Hubei University, Wuhan, 430062, China
| | - Binan Geng
- State Key Laboratory of Biocatalysis and Enzyme Engineering, and School of Life Sciences, Hubei University, Wuhan, 430062, China
| | - Shihui Yang
- State Key Laboratory of Biocatalysis and Enzyme Engineering, and School of Life Sciences, Hubei University, Wuhan, 430062, China
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2
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Xiao Y, Qin T, He S, Chen Y, Li H, He Q, Wang X, Yang S. Systematic investigation of TetR-family transcriptional regulators and their roles on lignocellulosic inhibitor acetate tolerance in Zymomonas mobilis. Front Bioeng Biotechnol 2024; 12:1385519. [PMID: 38585710 PMCID: PMC10998469 DOI: 10.3389/fbioe.2024.1385519] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/13/2024] [Accepted: 03/14/2024] [Indexed: 04/09/2024] Open
Abstract
TetR-family transcriptional regulators are widely distributed among bacteria and involved in various cellular processes such as multidrug and inhibitor resistance. Zymomonas mobilis is a industrial bacterium for lignocellulosic ethanol production. Although TetR-family regulators and their associated RND-family efflux pumps in Z. mobilis have been identified to be differentially expressed under various inhibitors and stressful conditions, there are no systematic investigation yet. In this study, bioinformatic analyses indicated that there are three TetR-family transcriptional regulators (ZMO0281, ZMO0963, ZMO1547) and two RND-family efflux pumps (ZMO0282-0285, ZMO0964-0966) adjacent to corresponding TetR-family regulators of ZMO0281 and ZMO0963 in Z. mobilis. Genetics studies were then carried out with various mutants of TetR-family regulators constructed, and ZMO0281 was characterized to be related to acetate tolerance. Combining transcriptomics and dual-reporter gene system, this study demonstrated that three TetR-family regulators repressed their adjacent genes specifically. Moreover, TetR-family regulator ZMO0281 might also be involved in other cellular processes in the presence of acetate. In addition, the upregulation of RND-family efflux pumps due to ZMO0281 deletion might lead to an energy imbalance and decreased cell growth in Z. mobilis under acetate stress. The systematic investigation of all three TetR-family regulators and their roles on a major lignocellulosic inhibitor acetate tolerance in Z. mobilis thus not only unravels the molecular mechanisms of TetR-family regulators and their potential cross-talks on regulating RND-family efflux pumps and other genes in Z. mobilis, but also provides guidance on understanding the roles of multiple regulators of same family in Z. mobilis and other microorganisms for efficient lignocellulosic biochemical production.
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Affiliation(s)
- Yubei Xiao
- State Key Laboratory of Biocatalysis and Enzyme Engineering, and School of Life Sciences, Hubei University, Wuhan, China
| | - Tongjia Qin
- State Key Laboratory of Biocatalysis and Enzyme Engineering, and School of Life Sciences, Hubei University, Wuhan, China
- Chinese Medicine College, Guangdong Yunfu Vocational College of Chinese Medicine, Guangzhou, Guangdong, China
| | - Shuche He
- State Key Laboratory of Biocatalysis and Enzyme Engineering, and School of Life Sciences, Hubei University, Wuhan, China
| | - Yunhao Chen
- State Key Laboratory of Biocatalysis and Enzyme Engineering, and School of Life Sciences, Hubei University, Wuhan, China
| | - Han Li
- State Key Laboratory of Biocatalysis and Enzyme Engineering, and School of Life Sciences, Hubei University, Wuhan, China
| | - Qiaoning He
- State Key Laboratory of Biocatalysis and Enzyme Engineering, and School of Life Sciences, Hubei University, Wuhan, China
| | - Xia Wang
- State Key Laboratory of Biocatalysis and Enzyme Engineering, and School of Life Sciences, Hubei University, Wuhan, China
| | - Shihui Yang
- State Key Laboratory of Biocatalysis and Enzyme Engineering, and School of Life Sciences, Hubei University, Wuhan, China
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3
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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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Zhang K, Zhang W, Qin M, Li Y, Wang H. Characterization and Application of the Sugar Transporter Zmo0293 from Zymomonas mobilis. Int J Mol Sci 2023; 24:ijms24065888. [PMID: 36982961 PMCID: PMC10055971 DOI: 10.3390/ijms24065888] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/03/2023] [Revised: 03/15/2023] [Accepted: 03/19/2023] [Indexed: 03/30/2023] Open
Abstract
Zymomonas mobilis is a natural ethanologen with many desirable characteristics, which makes it an ideal industrial microbial biocatalyst for the commercial production of desirable bioproducts. Sugar transporters are responsible for the import of substrate sugars and the conversion of ethanol and other products. Glucose-facilitated diffusion protein Glf is responsible for facilitating the diffusion of glucose uptake in Z. mobilis. However, another sugar transporter-encoded gene, ZMO0293, is poorly characterized. We employed gene deletion and heterologous expression mediated by the CRISPR/Cas method to investigate the role of ZMO0293. The results showed that deletion of the ZMO0293 gene slowed growth and reduced ethanol production and the activities of key enzymes involved in glucose metabolism in the presence of high concentrations of glucose. Moreover, ZMO0293 deletion caused different transcriptional changes in some genes of the Entner Doudoroff (ED) pathway in the ZM4-ΔZM0293 strain but not in ZM4 cells. The integrated expression of ZMO0293 restored the growth of the glucose uptake-defective strain Escherichia coli BL21(DE3)-ΔptsG. This study reveals the function of the ZMO0293 gene in Z. mobilis in response to high concentrations of glucose and provides a new biological part for synthetic biology.
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Affiliation(s)
- Kun Zhang
- Henan Province Engineering Laboratory for Bioconversion Technology of Functional Microbes, College of Life Sciences, Henan Normal University, Xinxiang 453007, China
| | - Wenwen Zhang
- Henan Province Engineering Laboratory for Bioconversion Technology of Functional Microbes, College of Life Sciences, Henan Normal University, Xinxiang 453007, China
| | - Mengxing Qin
- Henan Province Engineering Laboratory for Bioconversion Technology of Functional Microbes, College of Life Sciences, Henan Normal University, Xinxiang 453007, China
| | - Yi Li
- Henan Province Engineering Laboratory for Bioconversion Technology of Functional Microbes, College of Life Sciences, Henan Normal University, Xinxiang 453007, China
| | - Hailei Wang
- Henan Province Engineering Laboratory for Bioconversion Technology of Functional Microbes, College of Life Sciences, Henan Normal University, Xinxiang 453007, China
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5
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Guo Y, Zhao Y, Gao Y, Wang G, Zhao Y, Zhang J, Li Y, Wang X, Liu J, Chen G. Low acyl gellan gum immobilized Lactobacillus bulgaricus T15 produce D-lactic acid from non-detoxified corn stover hydrolysate. BIOTECHNOLOGY FOR BIOFUELS AND BIOPRODUCTS 2023; 16:43. [PMID: 36915198 PMCID: PMC10009946 DOI: 10.1186/s13068-023-02292-5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Subscribe] [Scholar Register] [Received: 11/25/2022] [Accepted: 02/28/2023] [Indexed: 03/16/2023]
Abstract
Straw biorefinery offers economical and sustainable production of chemicals. The merits of cell immobilization technology have become the key technology to meet D-lactic acid production from non- detoxified corn stover. In this paper, Low acyl gellan gum (LA-GAGR) was employed first time for Lactobacillus bulgaricus T15 immobilization and applied in D-lactic acid (D-LA) production from non-detoxified corn stover hydrolysate. Compared with the conventional calcium alginate (E404), LA-GAGR has a hencky stress of 82.09 kPa and excellent tolerance to 5-hydroxymethylfurfural (5-HMF), ferulic acid (FA), and vanillin. These features make LA-GAGR immobilized T15 work for 50 days via cell-recycle fermentation with D-LA yield of 2.77 ± 0.27 g/L h, while E404 immobilized T15 can only work for 30 days. The production of D-LA from non-detoxified corn stover hydrolysate with LA-GAGR immobilized T15 was also higher than that of free T15 fermentation and E404 immobilized T15 fermentation. In conclusion, LA-GAGR is an excellent cell immobilization material with great potential for industrial application in straw biorefinery industry.
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Affiliation(s)
- Yongxin Guo
- College of Life Science, Jilin Agricultural University, Jilin, 130118, China
| | - Yuru Zhao
- College of Life Science, Jilin Agricultural University, Jilin, 130118, China
| | - Yuan Gao
- College of Life Science, Jilin Agricultural University, Jilin, 130118, China.,Key Laboratory of Straw Comprehensive Utilization and Black Soil Conservation, Ministry of Education, Jilin Agricultural University, Jilin, 130118, China.,College of Food Science Technology and Chemical Engineering, Hubei University of Arts and Science, Hubei, 430000, China.,Sericultural Research Institute of Jilin Province, Jilin, China
| | - Gang Wang
- College of Life Science, Jilin Agricultural University, Jilin, 130118, China. .,Key Laboratory of Straw Comprehensive Utilization and Black Soil Conservation, Ministry of Education, Jilin Agricultural University, Jilin, 130118, China.
| | - Yixin Zhao
- College of Life Science, Jilin Agricultural University, Jilin, 130118, China
| | - Jiejing Zhang
- College of Life Science, Jilin Agricultural University, Jilin, 130118, China
| | - Yanli Li
- College of Life Science, Jilin Agricultural University, Jilin, 130118, China
| | - Xiqing Wang
- College of Food Science Technology and Chemical Engineering, Hubei University of Arts and Science, Hubei, 430000, China
| | - Juan Liu
- Sericultural Research Institute of Jilin Province, Jilin, China
| | - Guang Chen
- College of Life Science, Jilin Agricultural University, Jilin, 130118, China.,Key Laboratory of Straw Comprehensive Utilization and Black Soil Conservation, Ministry of Education, Jilin Agricultural University, Jilin, 130118, China
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6
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Hu M, Bao W, Peng Q, Hu W, Yang X, Xiang Y, Yan X, Li M, Xu P, He Q, Yang S. Metabolic engineering of Zymomonas mobilis for co-production of D-lactic acid and ethanol using waste feedstocks of molasses and corncob residue hydrolysate. Front Bioeng Biotechnol 2023; 11:1135484. [PMID: 36896016 PMCID: PMC9989019 DOI: 10.3389/fbioe.2023.1135484] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/31/2022] [Accepted: 02/08/2023] [Indexed: 02/25/2023] Open
Abstract
Lactate is the precursor for polylactide. In this study, a lactate producer of Z. mobilis was constructed by replacing ZMO0038 with LmldhA gene driven by a strong promoter PadhB, replacing ZMO1650 with native pdc gene driven by Ptet, and replacing native pdc with another copy of LmldhA driven by PadhB to divert carbon from ethanol to D-lactate. The resultant strain ZML-pdc-ldh produced 13.8 ± 0.2 g/L lactate and 16.9 ± 0.3 g/L ethanol using 48 g/L glucose. Lactate production of ZML-pdc-ldh was further investigated after fermentation optimization in pH-controlled fermenters. ZML-pdc-ldh produced 24.2 ± 0.6 g/L lactate and 12.9 ± 0.8 g/L ethanol as well as 36.2 ± 1.0 g/L lactate and 40.3 ± 0.3 g/L ethanol, resulting in total carbon conversion rate of 98.3% ± 2.5% and 96.2% ± 0.1% with final product productivity of 1.9 ± 0.0 g/L/h and 2.2 ± 0.0 g/L/h in RMG5 and RMG12, respectively. Moreover, ZML-pdc-ldh produced 32.9 ± 0.1 g/L D-lactate and 27.7 ± 0.2 g/L ethanol as well as 42.8 ± 0.0 g/L D-lactate and 53.1 ± 0.7 g/L ethanol with 97.1% ± 0.0% and 99.1% ± 0.8% carbon conversion rate using 20% molasses or corncob residue hydrolysate, respectively. Our study thus demonstrated that it is effective for lactate production by fermentation condition optimization and metabolic engineering to strengthen heterologous ldh expression while reducing the native ethanol production pathway. The capability of recombinant lactate-producer of Z. mobilis for efficient waste feedstock conversion makes it a promising biorefinery platform for carbon-neutral biochemical production.
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Affiliation(s)
- Mimi Hu
- State Key Laboratory of Biocatalysis and Enzyme Engineering, and School of Life Sciences, Hubei University, Wuhan, China
| | - Weiwei Bao
- State Key Laboratory of Biocatalysis and Enzyme Engineering, and School of Life Sciences, Hubei University, Wuhan, China
| | - Qiqun Peng
- State Key Laboratory of Biocatalysis and Enzyme Engineering, and School of Life Sciences, Hubei University, Wuhan, China
| | - Wei Hu
- Institute of Modern Physics, Chinese Academy of Sciences, Lanzhou, China
| | - Xinyu Yang
- State Key Laboratory of Biocatalysis and Enzyme Engineering, and School of Life Sciences, Hubei University, Wuhan, China
| | - Yan Xiang
- State Key Laboratory of Biocatalysis and Enzyme Engineering, and School of Life Sciences, Hubei University, Wuhan, China
| | - Xiongying Yan
- State Key Laboratory of Biocatalysis and Enzyme Engineering, and School of Life Sciences, Hubei University, Wuhan, China
| | - Mian Li
- Zhejiang Huakang Pharmaceutical Co., Ltd., Kaihua County, China
| | - Ping Xu
- State Key Laboratory of Microbial Metabolism, and School of Life Science and Biotechnology, Shanghai Jiao Tong University, Shanghai, China
| | - Qiaoning He
- State Key Laboratory of Biocatalysis and Enzyme Engineering, and School of Life Sciences, Hubei University, Wuhan, China
| | - Shihui Yang
- State Key Laboratory of Biocatalysis and Enzyme Engineering, and School of Life Sciences, Hubei University, Wuhan, China
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Behrendt G, Frohwitter J, Vlachonikolou M, Klamt S, Bettenbrock K. Zymo-Parts: A Golden Gate Modular Cloning Toolbox for Heterologous Gene Expression in Zymomonas mobilis. ACS Synth Biol 2022; 11:3855-3864. [PMID: 36346889 PMCID: PMC9680023 DOI: 10.1021/acssynbio.2c00428] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Zymomonas mobilis is a microorganism with extremely high sugar consumption and ethanol production rates and is generally considered to hold great potential for biotechnological applications. However, its genetic engineering is still difficult, hampering the efficient construction of genetically modified strains. In this work, we present Zymo-Parts, a modular toolbox based on Golden-Gate cloning offering a collection of promoters (including native, inducible, and synthetic constitutive promoters of varying strength), an array of terminators and several synthetic ribosomal binding sites and reporter genes. All these parts can be combined in an efficient and flexible way to achieve a desired level of gene expression, either from plasmids or via genome integration. Use of the GoldenBraid-based system also enables an assembly of operons consisting of up to five genes. We present the basic structure of the Zymo-Parts cloning system, characterize several constitutive and inducible promoters, and exemplify the construction of an operon and of chromosomal integration of a reporter gene. Finally, we demonstrate the power and utility of the Zymo-Parts toolbox for metabolic engineering applications by overexpressing a heterologous gene encoding for the lactate dehydrogenase of Escherichia coli to achieve different levels of lactate production in Z. mobilis.
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8
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Geng B, Huang X, Wu Y, He Q, Yang S. Identification and Characterization of Genes Related to Ampicillin Antibiotic Resistance in Zymomonas mobilis. Antibiotics (Basel) 2022; 11:1476. [PMID: 36358131 PMCID: PMC9686808 DOI: 10.3390/antibiotics11111476] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/10/2022] [Revised: 10/18/2022] [Accepted: 10/24/2022] [Indexed: 10/15/2023] Open
Abstract
Antibiotics can inhibit or kill microorganisms, while microorganisms have evolved antibiotic resistance strategies to survive antibiotics. Zymomonas mobilis is an ideal industrial microbial chassis and can tolerate multiple antibiotics. However, the mechanisms of antibiotic resistance and genes associated with antibiotic resistance have not been fully analyzed and characterized. In this study, we investigated genes associated with antibiotic resistance using bioinformatic approaches and examined genes associated with ampicillin resistance using CRISPR/Cas12a-based genome-editing technology. Six ampicillin-resistant genes (ZMO0103, ZMO0893, ZMO1094, ZMO1650, ZMO1866, and ZMO1967) were identified, and five mutant strains ZM4∆0103, ZM4∆0893, ZM4∆1094, ZM4∆1650, and ZM4∆1866 were constructed. Additionally, a four-gene mutant ZM4∆ARs was constructed by knocking out ZMO0103, ZMO0893, ZMO1094, and ZMO1650 continuously. Cell growth, morphology, and transformation efficiency of mutant strains were examined. Our results show that the cell growth of ZM4∆0103 and ZM4∆ARs was significantly inhibited with 150 μg/mL ampicillin, and cells changed to a long filament shape from a short rod shape. Moreover, the transformation efficiencies of ZM4∆0103 and ZM4∆ARs were decreased. Our results indicate that ZMO0103 is the key to ampicillin resistance in Z. mobilis, and other ampicillin-resistant genes may have a synergetic effect with it. In summary, this study identified and characterized genes related to ampicillin resistance in Z. mobilis and laid a foundation for further study of other antibiotic resistance mechanisms.
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Affiliation(s)
| | | | | | - Qiaoning He
- State Key Laboratory of Biocatalysis and Enzyme Engineering, Environmental Microbial Technology Center of Hubei Province, School of Life Sciences, Hubei University, Wuhan 430062, China
| | - Shihui Yang
- State Key Laboratory of Biocatalysis and Enzyme Engineering, Environmental Microbial Technology Center of Hubei Province, School of Life Sciences, Hubei University, Wuhan 430062, China
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9
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Song H, Yang Y, Li H, Du J, Hu Z, Chen Y, Yang N, Mei M, Xiong Z, Tang K, Yi L, Zhang Y, Yang S. Determination of Nucleotide Sequences within Promoter Regions Affecting Promoter Compatibility between Zymomonas mobilis and Escherichia coli. ACS Synth Biol 2022; 11:2811-2819. [PMID: 35771099 DOI: 10.1021/acssynbio.2c00187] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
A promoter plays a crucial role in controlling the expression of the target gene in cells, thus being one of the key biological parts for synthetic biology practices. Although significant efforts have been made to identify and characterize promoters with different strengths in various microorganisms, the compatibility of promoters within different hosts still lacks investigation. In this study, we chose the native Pgap promoter of Zymomonas mobilis to investigate nucleotide sequences within promoter regions affecting promoter compatibility between Escherichia coli and Z. mobilis. Pgap is one of the strongest promotors in Z. mobilis that has many excellent characteristics to be developed as microbial cell factories. Using EGFP as a reporter, a Z. mobilis-derived Pgap mutant library was constructed and sorted in E. coli, with candidate promoters exhibiting high fluorescence intensity collected. A total of 53 variants were finally selected and sequenced by Sanger sequencing. The sequencing results grouped these variants into 12 different Pgap variant types, among which seven types presented higher promoter strength than native Pgap in E. coli. The next-generation sequencing technique was then employed to identify key mutations within the Pgap promoter region that affect the promoter compatibility. Finally, six important sites were identified and confirmed to help increase Pgap strength in E. coli while keeping similar strength of native Pgap in Z. mobilis. Compared to native Pgap, synthetic promoters combining these sites had enhanced strength; especially, Pgap-6M combining all six sites exhibited 20-fold greater strength than native Pgap in E. coli. This study thus not only determined six important sites affecting promoter compatibility but also confirmed a series of Pgap promoter variants with strong promoter activity in both E. coli and Z. mobilis. In addition, a strategy was established in this study to investigate and determine nucleotide sequences in promoter regions affecting promoter compatibility, which can be applied in other microorganisms to help reveal universal factors affecting promoter compatibility and design promoters with desired strengths among different microbial cell factories.
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Affiliation(s)
- Haoyue Song
- State Key Laboratory of Biocatalysis and Enzyme Engineering, and School of Life Sciences, Hubei University, Wuhan 430062, China
| | - Yongfu Yang
- State Key Laboratory of Biocatalysis and Enzyme Engineering, and School of Life Sciences, Hubei University, Wuhan 430062, China
| | - Han Li
- State Key Laboratory of Biocatalysis and Enzyme Engineering, and School of Life Sciences, Hubei University, Wuhan 430062, China
| | - Jun Du
- Beijing Tsingke Biotechnology Co., Ltd., Beijing 101111, China
| | - Zhousheng Hu
- State Key Laboratory of Biocatalysis and Enzyme Engineering, and School of Life Sciences, Hubei University, Wuhan 430062, China
| | - Yunhao Chen
- State Key Laboratory of Biocatalysis and Enzyme Engineering, and School of Life Sciences, Hubei University, Wuhan 430062, China
| | - Ning Yang
- State Key Laboratory of Biocatalysis and Enzyme Engineering, and School of Life Sciences, Hubei University, Wuhan 430062, China
| | - Meng Mei
- State Key Laboratory of Biocatalysis and Enzyme Engineering, and School of Life Sciences, Hubei University, Wuhan 430062, China
| | - Zhiqiang Xiong
- State Key Laboratory of Biocatalysis and Enzyme Engineering, and School of Life Sciences, Hubei University, Wuhan 430062, China
| | - Ke Tang
- State Key Laboratory of Biocatalysis and Enzyme Engineering, and School of Life Sciences, Hubei University, Wuhan 430062, China
| | - Li Yi
- State Key Laboratory of Biocatalysis and Enzyme Engineering, and School of Life Sciences, Hubei University, Wuhan 430062, China
| | - Yu Zhang
- Key Laboratory of Synthetic Biology, CAS Center for Excellence in Molecular Plant Sciences, Shanghai Institute of Plant Physiology and Ecology, Chinese Academy of Sciences, Shanghai 200032, China
| | - Shihui Yang
- State Key Laboratory of Biocatalysis and Enzyme Engineering, and School of Life Sciences, Hubei University, Wuhan 430062, China
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10
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Khandelwal R, Jain D, Jaishankar J, Barman A, Srivastava P, Bisaria VS. Characterization of Zymomonas mobilis promoters that are functional in Escherichia coli. J Biosci Bioeng 2022; 133:301-308. [DOI: 10.1016/j.jbiosc.2021.12.012] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/11/2021] [Revised: 12/19/2021] [Accepted: 12/26/2021] [Indexed: 02/08/2023]
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11
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Braga A, Gomes D, Rainha J, Amorim C, Cardoso BB, Gudiña EJ, Silvério SC, Rodrigues JL, Rodrigues LR. Zymomonas mobilis as an emerging biotechnological chassis for the production of industrially relevant compounds. BIORESOUR BIOPROCESS 2021; 8:128. [PMID: 38650193 PMCID: PMC10992037 DOI: 10.1186/s40643-021-00483-2] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/04/2021] [Accepted: 12/06/2021] [Indexed: 11/10/2022] Open
Abstract
Zymomonas mobilis is a well-recognized ethanologenic bacterium with outstanding characteristics which make it a promising platform for the biotechnological production of relevant building blocks and fine chemicals compounds. In the last years, research has been focused on the physiological, genetic, and metabolic engineering strategies aiming at expanding Z. mobilis ability to metabolize lignocellulosic substrates toward biofuel production. With the expansion of the Z. mobilis molecular and computational modeling toolbox, the potential of this bacterium as a cell factory has been thoroughly explored. The number of genomic, transcriptomic, proteomic, and fluxomic data that is becoming available for this bacterium has increased. For this reason, in the forthcoming years, systems biology is expected to continue driving the improvement of Z. mobilis for current and emergent biotechnological applications. While the existing molecular toolbox allowed the creation of stable Z. mobilis strains with improved traits for pinpointed biotechnological applications, the development of new and more flexible tools is crucial to boost the engineering capabilities of this bacterium. Novel genetic toolkits based on the CRISPR-Cas9 system and recombineering have been recently used for the metabolic engineering of Z. mobilis. However, they are mostly at the proof-of-concept stage and need to be further improved.
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Affiliation(s)
- Adelaide Braga
- CEB-Centre of Biological Engineering, Universidade Do Minho, Campus de Gualtar, 4710-057, Braga, Portugal
| | - Daniela Gomes
- CEB-Centre of Biological Engineering, Universidade Do Minho, Campus de Gualtar, 4710-057, Braga, Portugal
| | - João Rainha
- CEB-Centre of Biological Engineering, Universidade Do Minho, Campus de Gualtar, 4710-057, Braga, Portugal
| | - Cláudia Amorim
- CEB-Centre of Biological Engineering, Universidade Do Minho, Campus de Gualtar, 4710-057, Braga, Portugal
| | - Beatriz B Cardoso
- CEB-Centre of Biological Engineering, Universidade Do Minho, Campus de Gualtar, 4710-057, Braga, Portugal
| | - Eduardo J Gudiña
- CEB-Centre of Biological Engineering, Universidade Do Minho, Campus de Gualtar, 4710-057, Braga, Portugal
| | - Sara C Silvério
- CEB-Centre of Biological Engineering, Universidade Do Minho, Campus de Gualtar, 4710-057, Braga, Portugal
| | - Joana L Rodrigues
- CEB-Centre of Biological Engineering, Universidade Do Minho, Campus de Gualtar, 4710-057, Braga, Portugal
| | - Lígia R Rodrigues
- CEB-Centre of Biological Engineering, Universidade Do Minho, Campus de Gualtar, 4710-057, Braga, Portugal.
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12
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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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13
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Li R, Shen W, Yang Y, Du J, Li M, Yang S. Investigation of the impact of a broad range of temperatures on the physiological and transcriptional profiles of Zymomonas mobilis ZM4 for high-temperature-tolerant recombinant strain development. BIOTECHNOLOGY FOR BIOFUELS 2021; 14:146. [PMID: 34176507 PMCID: PMC8237431 DOI: 10.1186/s13068-021-02000-1] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/28/2021] [Accepted: 06/18/2021] [Indexed: 05/11/2023]
Abstract
The model ethanologenic bacterium Zymomonas mobilis has many advantages for diverse biochemical production. Although the impact of temperature especially high temperature on the growth and ethanol production of Z. mobilis has been reported, the transcriptional profiles of Z. mobilis grown at different temperatures have not been systematically investigated. In this study, Z. mobilis wild-type strain ZM4 was used to study the effect of a broad range of temperatures of 24, 30, 36, 40, and 45 °C on cell growth and morphology, glucose utilization and ethanol production, as well as the corresponding global gene expression profiles using RNA-Seq-based transcriptomics. In addition, a recombinant Z. mobilis strain expressing reporter gene EGFP (ZM4_EGFP) was constructed to study the effect of temperature on heterologous protein expression at different temperatures. Our result demonstrated that the effect of temperature on the growth and morphology of ZM4 and ZM4_EGFP were similar. The biomass of these two strains decreased along with the temperature increase, and an optimal temperature range is needed for efficient glucose utilization and ethanol production. Temperatures lower or higher than normal temperature investigated in this work was not favorable for the glucose utilization and ethanol production as well as the expression of exogenous protein EGFP based on the results of flow cytometry and Western blot. Temperature also affected the transcriptional profiles of Z. mobilis especially under high temperature. Compared with ZM4 cultured at 30 °C, 478 genes were up-regulated and 481 genes were down-regulated at 45 °C. The number of differentially expressed genes of ZM4 cultured at other temperatures (24, 36 or 40 °C) was relatively small though compared with those at 30 °C. Since temperature usually increases during the fermentation process, and heat tolerance is one of the important robustness traits of industrial strains, candidate genes related to heat resistance based on our RNA-Seq result and literature report were then selected for genetics study using the strategies of plasmid overexpression of candidate gene or replacement of the native promoter of candidate gene by an inducible Ptet promoter. The genetics studies indicated that ZMO0236, ZMO1335, ZMO0994, operon groESL, and cspL, which encodes Mrp family chromosome partitioning ATPase, flavoprotein WrbA, an uncharacterized protein, chaperonin Cpn10 and GroEL, and an exogenous cold shock protein, respectively, were associated with heat tolerance, and recombinant strains over-expressing these genes can improve their heat tolerance. Our work thus not only explored the effects of temperature on the expression of exogenous gene EGFP and endogenous genes, but also selected and confirmed several genes associated with heat tolerance in Z. mobilis, which provided a guidance on identifying candidate genes associated with phenotypic improvement through systems biology strategy and genetics studies for other microorganisms.
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Affiliation(s)
- Runxia Li
- State Key Laboratory of Biocatalysis and Enzyme Engineering, Environmental Microbial Technology Center of Hubei Province, and School of Life Sciences, Hubei University, Wuhan, 430062 China
| | - Wei Shen
- Department of Biological and Chemical Engineering, Zhixing College of Hubei University, Wuhan, 430011 China
| | - Yongfu Yang
- State Key Laboratory of Biocatalysis and Enzyme Engineering, Environmental Microbial Technology Center of Hubei Province, and School of Life Sciences, Hubei University, Wuhan, 430062 China
| | - Jun Du
- China Biotech Fermentation Industry Association, Beijing, 100833 China
| | - Mian Li
- Zhejiang Huakang Pharmaceutical Co., Ltd., Kaihua County, Zhejiang China
| | - Shihui Yang
- State Key Laboratory of Biocatalysis and Enzyme Engineering, Environmental Microbial Technology Center of Hubei Province, and School of Life Sciences, Hubei University, Wuhan, 430062 China
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14
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Developing a Riboswitch-Mediated Regulatory System for Metabolic Flux Control in Thermophilic Bacillus methanolicus. Int J Mol Sci 2021; 22:ijms22094686. [PMID: 33925231 PMCID: PMC8124236 DOI: 10.3390/ijms22094686] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/12/2021] [Revised: 04/22/2021] [Accepted: 04/27/2021] [Indexed: 12/05/2022] Open
Abstract
Genome-wide transcriptomic data obtained in RNA-seq experiments can serve as a reliable source for identification of novel regulatory elements such as riboswitches and promoters. Riboswitches are parts of the 5′ untranslated region of mRNA molecules that can specifically bind various metabolites and control gene expression. For that reason, they have become an attractive tool for engineering biological systems, especially for the regulation of metabolic fluxes in industrial microorganisms. Promoters in the genomes of prokaryotes are located upstream of transcription start sites and their sequences are easily identifiable based on the primary transcriptome data. Bacillus methanolicus MGA3 is a candidate for use as an industrial workhorse in methanol-based bioprocesses and its metabolism has been studied in systems biology approaches in recent years, including transcriptome characterization through RNA-seq. Here, we identify a putative lysine riboswitch in B. methanolicus, and test and characterize it. We also select and experimentally verify 10 putative B. methanolicus-derived promoters differing in their predicted strength and present their functionality in combination with the lysine riboswitch. We further explore the potential of a B. subtilis-derived purine riboswitch for regulation of gene expression in the thermophilic B. methanolicus, establishing a novel tool for inducible gene expression in this bacterium.
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15
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Riley LA, Guss AM. Approaches to genetic tool development for rapid domestication of non-model microorganisms. BIOTECHNOLOGY FOR BIOFUELS 2021; 14:30. [PMID: 33494801 PMCID: PMC7830746 DOI: 10.1186/s13068-020-01872-z] [Citation(s) in RCA: 48] [Impact Index Per Article: 16.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/16/2020] [Accepted: 12/30/2020] [Indexed: 05/04/2023]
Abstract
Non-model microorganisms often possess complex phenotypes that could be important for the future of biofuel and chemical production. They have received significant interest the last several years, but advancement is still slow due to the lack of a robust genetic toolbox in most organisms. Typically, "domestication" of a new non-model microorganism has been done on an ad hoc basis, and historically, it can take years to develop transformation and basic genetic tools. Here, we review the barriers and solutions to rapid development of genetic transformation tools in new hosts, with a major focus on Restriction-Modification systems, which are a well-known and significant barrier to efficient transformation. We further explore the tools and approaches used for efficient gene deletion, DNA insertion, and heterologous gene expression. Finally, more advanced and high-throughput tools are now being developed in diverse non-model microbes, paving the way for rapid and multiplexed genome engineering for biotechnology.
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Affiliation(s)
- Lauren A Riley
- Biosciences Division, Oak Ridge National Laboratory, Oak Ridge, TN, 37831, USA
- Bredesen Center, University of Tennessee, Knoxville, TN, 37996, USA
| | - Adam M Guss
- Biosciences Division, Oak Ridge National Laboratory, Oak Ridge, TN, 37831, USA.
- Bredesen Center, University of Tennessee, Knoxville, TN, 37996, USA.
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16
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Banta AB, Enright AL, Siletti C, Peters JM. A High-Efficacy CRISPR Interference System for Gene Function Discovery in Zymomonas mobilis. Appl Environ Microbiol 2020; 86:e01621-20. [PMID: 32978126 PMCID: PMC7657623 DOI: 10.1128/aem.01621-20] [Citation(s) in RCA: 23] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/03/2020] [Accepted: 09/20/2020] [Indexed: 01/23/2023] Open
Abstract
Zymomonas mobilis is a promising biofuel producer due to its high alcohol tolerance and streamlined metabolism that efficiently converts sugar to ethanol. Z. mobilis genes are poorly characterized relative to those of model bacteria, hampering our ability to rationally engineer the genome with pathways capable of converting sugars from plant hydrolysates into valuable biofuels and bioproducts. Many of the unique properties that make Z. mobilis an attractive biofuel producer are controlled by essential genes; however, these genes cannot be manipulated using traditional genetic approaches (e.g., deletion or transposon insertion) because they are required for viability. CRISPR interference (CRISPRi) is a programmable gene knockdown system that can precisely control the timing and extent of gene repression, thus enabling targeting of essential genes. Here, we establish a stable, high-efficacy CRISPRi system in Z. mobilis that is capable of perturbing all genes-including essential genes. We show that Z. mobilis CRISPRi causes either strong knockdowns (>100-fold) using single guide RNA (sgRNA) spacers that perfectly match target genes or partial knockdowns using spacers with mismatches. We demonstrate the efficacy of Z. mobilis CRISPRi by targeting essential genes that are universally conserved in bacteria, are key to the efficient metabolism of Z. mobilis, or underlie alcohol tolerance. Our Z. mobilis CRISPRi system will enable comprehensive gene function discovery, opening a path to rational design of biofuel production strains with improved yields.IMPORTANCE Biofuels produced by microbial fermentation of plant feedstocks provide renewable and sustainable energy sources that have the potential to mitigate climate change and improve energy security. Engineered strains of the bacterium Z. mobilis can convert sugars extracted from plant feedstocks into next-generation biofuels like isobutanol; however, conversion by these strains remains inefficient due to key gaps in our knowledge about genes involved in metabolism and stress responses such as alcohol tolerance. Here, we develop CRISPRi as a tool to explore gene function in Z. mobilis We characterize genes that are essential for growth, required to ferment sugar to ethanol, and involved in resistance to isobutanol. Our Z. mobilis CRISPRi system makes it straightforward to define gene function and can be applied to improve strain engineering and increase biofuel yields.
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Affiliation(s)
- Amy B Banta
- Pharmaceutical Sciences Division, School of Pharmacy, University of Wisconsin-Madison, Madison, Wisconsin, USA
- Great Lakes Bioenergy Research Center, Wisconsin Energy Institute, University of Wisconsin-Madison, Madison, Wisconsin, USA
| | - Amy L Enright
- Pharmaceutical Sciences Division, School of Pharmacy, University of Wisconsin-Madison, Madison, Wisconsin, USA
- Great Lakes Bioenergy Research Center, Wisconsin Energy Institute, University of Wisconsin-Madison, Madison, Wisconsin, USA
| | - Cheta Siletti
- Pharmaceutical Sciences Division, School of Pharmacy, University of Wisconsin-Madison, Madison, Wisconsin, USA
| | - Jason M Peters
- Pharmaceutical Sciences Division, School of Pharmacy, University of Wisconsin-Madison, Madison, Wisconsin, USA
- Great Lakes Bioenergy Research Center, Wisconsin Energy Institute, University of Wisconsin-Madison, Madison, Wisconsin, USA
- Department of Bacteriology, University of Wisconsin-Madison, Madison, Wisconsin, USA
- Department of Medical Microbiology and Immunology, University of Wisconsin-Madison, Madison, Wisconsin, USA
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17
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Genome-Scale Transcription-Translation Mapping Reveals Features of Zymomonas mobilis Transcription Units and Promoters. mSystems 2020; 5:5/4/e00250-20. [PMID: 32694125 PMCID: PMC7566282 DOI: 10.1128/msystems.00250-20] [Citation(s) in RCA: 17] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022] Open
Abstract
Efforts to rationally engineer synthetic pathways in Zymomonas mobilis are impeded by a lack of knowledge and tools for predictable and quantitative programming of gene regulation at the transcriptional, posttranscriptional, and posttranslational levels. With the detailed functional characterization of the Z. mobilis genome presented in this work, we provide crucial knowledge for the development of synthetic genetic parts tailored to Z. mobilis. This information is vital as researchers continue to develop Z. mobilis for synthetic biology applications. Our methods and statistical analyses also provide ways to rapidly advance the understanding of poorly characterized bacteria via empirical data that enable the experimental validation of sequence-based prediction for genome characterization and annotation. Zymomonas mobilis is an ethanologenic alphaproteobacterium with promise for the industrial conversion of renewable plant biomass into fuels and chemical bioproducts. Limited functional annotation of the Z. mobilis genome is a current barrier to both fundamental studies of Z. mobilis and its development as a synthetic biology chassis. To gain insight, we collected sample-matched multiomics data, including RNA sequencing (RNA-seq), transcription start site (TSS) sequencing (TSS-seq), termination sequencing (term-seq), ribosome profiling, and label-free shotgun proteomic mass spectrometry, across different growth conditions and used these data to improve annotation and assign functional sites in the Z. mobilis genome. Proteomics and ribosome profiling informed revisions of protein-coding genes, which included 44 start codon changes and 42 added proteins. We developed statistical methods for annotating transcript 5′ and 3′ ends, enabling the identification of 3,940 TSSs and their corresponding promoters and 2,091 transcription termination sites, which were distinguished from RNA processing sites by the lack of an adjacent RNA 5′ end. Our results revealed that Z. mobilis σA −35 and −10 promoter elements closely resemble canonical Escherichia coli −35 and −10 elements, with one notable exception: the Z. mobilis −10 element lacks the highly conserved −7 thymine observed in E. coli and other previously characterized σA promoters. The σA promoters of another alphaproteobacterium, Caulobacter crescentus, similarly lack the conservation of −7 thymine in their −10 elements. Our results anchor the development of Z. mobilis as a platform for synthetic biology and establish strategies for empirical genome annotation that can complement purely computational methods. IMPORTANCE Efforts to rationally engineer synthetic pathways in Zymomonas mobilis are impeded by a lack of knowledge and tools for predictable and quantitative programming of gene regulation at the transcriptional, posttranscriptional, and posttranslational levels. With the detailed functional characterization of the Z. mobilis genome presented in this work, we provide crucial knowledge for the development of synthetic genetic parts tailored to Z. mobilis. This information is vital as researchers continue to develop Z. mobilis for synthetic biology applications. Our methods and statistical analyses also provide ways to rapidly advance the understanding of poorly characterized bacteria via empirical data that enable the experimental validation of sequence-based prediction for genome characterization and annotation.
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18
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Liu Y, Ghosh IN, Martien J, Zhang Y, Amador-Noguez D, Landick R. Regulated redirection of central carbon flux enhances anaerobic production of bioproducts in Zymomonas mobilis. Metab Eng 2020; 61:261-274. [PMID: 32590077 DOI: 10.1016/j.ymben.2020.06.005] [Citation(s) in RCA: 20] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/26/2020] [Revised: 06/06/2020] [Accepted: 06/07/2020] [Indexed: 01/25/2023]
Abstract
The microbial production of chemicals and fuels from plant biomass offers a sustainable alternative to fossilized carbon but requires high rates and yields of bioproduct synthesis. Z. mobilis is a promising chassis microbe due to its high glycolytic rate in anaerobic conditions that are favorable for large-scale production. However, diverting flux from its robust ethanol fermentation pathway to nonnative pathways remains a major engineering hurdle. To enable controlled, high-yield synthesis of bioproducts, we implemented a central-carbon metabolism control-valve strategy using regulated, ectopic expression of pyruvate decarboxylase (Pdc) and deletion of chromosomal pdc. Metabolomic and genetic analyses revealed that glycolytic intermediates and NADH accumulate when Pdc is depleted and that Pdc is essential for anaerobic growth of Z. mobilis. Aerobically, all flux can be redirected to a 2,3-butanediol pathway for which respiration maintains redox balance. Anaerobically, flux can be redirected to redox-balanced lactate or isobutanol pathways with ≥65% overall yield from glucose. This strategy provides a promising path for future metabolic engineering of Z. mobilis.
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Affiliation(s)
- Yang Liu
- Department of Biochemistry, University of Wisconsin-Madison, Madison, WI, 53706, United States; DOE Great Lakes Bioenergy Research Center, University of Wisconsin-Madison, Madison, WI, 53726, United States
| | - Indro Neil Ghosh
- DOE Great Lakes Bioenergy Research Center, University of Wisconsin-Madison, Madison, WI, 53726, United States
| | - Julia Martien
- Department of Bacteriology, University of Wisconsin-Madison, Madison, WI, 53706, United States; DOE Great Lakes Bioenergy Research Center, University of Wisconsin-Madison, Madison, WI, 53726, United States
| | - Yaoping Zhang
- DOE Great Lakes Bioenergy Research Center, University of Wisconsin-Madison, Madison, WI, 53726, United States
| | - Daniel Amador-Noguez
- Department of Bacteriology, University of Wisconsin-Madison, Madison, WI, 53706, United States; DOE Great Lakes Bioenergy Research Center, University of Wisconsin-Madison, Madison, WI, 53726, United States
| | - Robert Landick
- Department of Biochemistry, University of Wisconsin-Madison, Madison, WI, 53706, United States; Department of Bacteriology, University of Wisconsin-Madison, Madison, WI, 53706, United States; DOE Great Lakes Bioenergy Research Center, University of Wisconsin-Madison, Madison, WI, 53726, United States.
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19
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Zheng Y, Han J, Wang B, Hu X, Li R, Shen W, Ma X, Ma L, Yi L, Yang S, Peng W. Characterization and repurposing of the endogenous Type I-F CRISPR-Cas system of Zymomonas mobilis for genome engineering. Nucleic Acids Res 2020; 47:11461-11475. [PMID: 31647102 PMCID: PMC6868425 DOI: 10.1093/nar/gkz940] [Citation(s) in RCA: 72] [Impact Index Per Article: 18.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/13/2019] [Revised: 10/05/2019] [Accepted: 10/09/2019] [Indexed: 12/19/2022] Open
Abstract
Application of CRISPR-based technologies in non-model microorganisms is currently very limited. Here, we reported efficient genome engineering of an important industrial microorganism, Zymomonas mobilis, by repurposing the endogenous Type I-F CRISPR–Cas system upon its functional characterization. This toolkit included a series of genome engineering plasmids, each carrying an artificial self-targeting CRISPR and a donor DNA for the recovery of recombinants. Through this toolkit, various genome engineering purposes were efficiently achieved, including knockout of ZMO0038 (100% efficiency), cas2/3 (100%), and a genomic fragment of >10 kb (50%), replacement of cas2/3 with mCherry gene (100%), in situ nucleotide substitution (100%) and His-tagging of ZMO0038 (100%), and multiplex gene deletion (18.75%) upon optimal donor size determination. Additionally, the Type I-F system was further applied for CRISPRi upon Cas2/3 depletion, which has been demonstrated to successfully silence the chromosomally integrated mCherry gene with its fluorescence intensity reduced by up to 88%. Moreover, we demonstrated that genome engineering efficiency could be improved under a restriction–modification (R–M) deficient background, suggesting the perturbance of genome editing by other co-existing DNA targeting modules such as the R–M system. This study might shed light on exploiting and improving CRISPR–Cas systems in other microorganisms for genome editing and metabolic engineering practices.
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Affiliation(s)
- Yanli Zheng
- State Key Laboratory of Biocatalysis and Enzyme Engineering, Hubei Engineering Research Center for Bio-enzyme Catalysis, Environmental Microbial Technology Center of Hubei Province, Hubei Collaborative Innovation Center for Green Transformation of Bio-resources, School of Life Sciences, Hubei University, Wuhan 430062, P.R. China
| | - Jiamei Han
- State Key Laboratory of Biocatalysis and Enzyme Engineering, Hubei Engineering Research Center for Bio-enzyme Catalysis, Environmental Microbial Technology Center of Hubei Province, Hubei Collaborative Innovation Center for Green Transformation of Bio-resources, School of Life Sciences, Hubei University, Wuhan 430062, P.R. China
| | - Baiyang Wang
- State Key Laboratory of Biocatalysis and Enzyme Engineering, Hubei Engineering Research Center for Bio-enzyme Catalysis, Environmental Microbial Technology Center of Hubei Province, Hubei Collaborative Innovation Center for Green Transformation of Bio-resources, School of Life Sciences, Hubei University, Wuhan 430062, P.R. China
| | - Xiaoyun Hu
- State Key Laboratory of Biocatalysis and Enzyme Engineering, Hubei Engineering Research Center for Bio-enzyme Catalysis, Environmental Microbial Technology Center of Hubei Province, Hubei Collaborative Innovation Center for Green Transformation of Bio-resources, School of Life Sciences, Hubei University, Wuhan 430062, P.R. China
| | - Runxia Li
- State Key Laboratory of Biocatalysis and Enzyme Engineering, Hubei Engineering Research Center for Bio-enzyme Catalysis, Environmental Microbial Technology Center of Hubei Province, Hubei Collaborative Innovation Center for Green Transformation of Bio-resources, School of Life Sciences, Hubei University, Wuhan 430062, P.R. China
| | - Wei Shen
- State Key Laboratory of Biocatalysis and Enzyme Engineering, Hubei Engineering Research Center for Bio-enzyme Catalysis, Environmental Microbial Technology Center of Hubei Province, Hubei Collaborative Innovation Center for Green Transformation of Bio-resources, School of Life Sciences, Hubei University, Wuhan 430062, P.R. China
| | - Xiangdong Ma
- State Key Laboratory of Biocatalysis and Enzyme Engineering, Hubei Engineering Research Center for Bio-enzyme Catalysis, Environmental Microbial Technology Center of Hubei Province, Hubei Collaborative Innovation Center for Green Transformation of Bio-resources, School of Life Sciences, Hubei University, Wuhan 430062, P.R. China
| | - Lixin Ma
- State Key Laboratory of Biocatalysis and Enzyme Engineering, Hubei Engineering Research Center for Bio-enzyme Catalysis, Environmental Microbial Technology Center of Hubei Province, Hubei Collaborative Innovation Center for Green Transformation of Bio-resources, School of Life Sciences, Hubei University, Wuhan 430062, P.R. China
| | - Li Yi
- State Key Laboratory of Biocatalysis and Enzyme Engineering, Hubei Engineering Research Center for Bio-enzyme Catalysis, Environmental Microbial Technology Center of Hubei Province, Hubei Collaborative Innovation Center for Green Transformation of Bio-resources, School of Life Sciences, Hubei University, Wuhan 430062, P.R. China
| | - Shihui Yang
- State Key Laboratory of Biocatalysis and Enzyme Engineering, Hubei Engineering Research Center for Bio-enzyme Catalysis, Environmental Microbial Technology Center of Hubei Province, Hubei Collaborative Innovation Center for Green Transformation of Bio-resources, School of Life Sciences, Hubei University, Wuhan 430062, P.R. China
| | - Wenfang Peng
- State Key Laboratory of Biocatalysis and Enzyme Engineering, Hubei Engineering Research Center for Bio-enzyme Catalysis, Environmental Microbial Technology Center of Hubei Province, Hubei Collaborative Innovation Center for Green Transformation of Bio-resources, School of Life Sciences, Hubei University, Wuhan 430062, P.R. China
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Han R, Haning K, Gonzalez-Rivera JC, Yang Y, Li R, Cho SH, Huang J, Simonsen BA, Yang S, Contreras LM. Multiple Small RNAs Interact to Co-regulate Ethanol Tolerance in Zymomonas mobilis. Front Bioeng Biotechnol 2020; 8:155. [PMID: 32195236 PMCID: PMC7064620 DOI: 10.3389/fbioe.2020.00155] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/09/2019] [Accepted: 02/14/2020] [Indexed: 01/18/2023] Open
Abstract
sRNAs represent a powerful class of regulators that influences multiple mRNA targets in response to environmental changes. However, very few direct sRNA-sRNA interactions have been deeply studied in any organism. Zymomonas mobilis is a bacterium with unique ethanol-producing metabolic pathways in which multiple small RNAs (sRNAs) have recently been identified, some of which show differential expression in ethanol stress. In this study, we show that two sRNAs (Zms4 and Zms6) are upregulated under ethanol stress and have significant impacts on ethanol tolerance and production in Z. mobilis. We conducted multi-omics analysis (combining transcriptomics and sRNA-immunoprecipitation) to map gene networks under the influence of their regulation. We confirmed that Zms4 and Zms6 bind multiple RNA targets and regulate their expressions, influencing many downstream pathways important to ethanol tolerance and production. In particular, Zms4 and Zms6 interact with each other as well as many other sRNAs, forming a novel sRNA-sRNA direct interaction network. This study thus uncovers a sRNA network that co-orchestrates multiple ethanol related pathways through a diverse set of mRNA targets and a large number of sRNAs. To our knowledge, this study represents one of the largest sRNA-sRNA direct interactions uncovered so far.
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Affiliation(s)
- Runhua Han
- McKetta Department of Chemical Engineering, The University of Texas at Austin, Austin, TX, United States
| | - Katie Haning
- McKetta Department of Chemical Engineering, The University of Texas at Austin, Austin, TX, United States
| | - Juan C Gonzalez-Rivera
- McKetta Department of Chemical Engineering, The University of Texas at Austin, Austin, TX, United States
| | - Yongfu Yang
- State Key Laboratory of Biocatalysis and Enzyme Engineering, Hubei Collaborative Innovation Center for Green Transformation of Bio-resources, Environmental Microbial Technology Center of Hubei Province, and School of Life Sciences, Hubei University, Wuhan, China
| | - Runxia Li
- State Key Laboratory of Biocatalysis and Enzyme Engineering, Hubei Collaborative Innovation Center for Green Transformation of Bio-resources, Environmental Microbial Technology Center of Hubei Province, and School of Life Sciences, Hubei University, Wuhan, China
| | - Seung Hee Cho
- Institute for Cellular and Molecular Biology, College of Natural Sciences, The University of Texas at Austin, Austin, TX, United States
| | - Ju Huang
- State Key Laboratory of Biocatalysis and Enzyme Engineering, Hubei Collaborative Innovation Center for Green Transformation of Bio-resources, Environmental Microbial Technology Center of Hubei Province, and School of Life Sciences, Hubei University, Wuhan, China
| | - Bobi A Simonsen
- McKetta Department of Chemical Engineering, The University of Texas at Austin, Austin, TX, United States
| | - Shihui Yang
- State Key Laboratory of Biocatalysis and Enzyme Engineering, Hubei Collaborative Innovation Center for Green Transformation of Bio-resources, Environmental Microbial Technology Center of Hubei Province, and School of Life Sciences, Hubei University, Wuhan, China
| | - Lydia M Contreras
- McKetta Department of Chemical Engineering, The University of Texas at Austin, Austin, TX, United States.,Institute for Cellular and Molecular Biology, College of Natural Sciences, The University of Texas at Austin, Austin, TX, United States
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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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22
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Yang Q, Yang Y, Tang Y, Wang X, Chen Y, Shen W, Zhan Y, Gao J, Wu B, He M, Chen S, Yang S. Development and characterization of acidic-pH-tolerant mutants of Zymomonas mobilis through adaptation and next-generation sequencing-based genome resequencing and RNA-Seq. BIOTECHNOLOGY FOR BIOFUELS 2020; 13:144. [PMID: 32817760 PMCID: PMC7427070 DOI: 10.1186/s13068-020-01781-1] [Citation(s) in RCA: 24] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/03/2020] [Accepted: 08/04/2020] [Indexed: 05/19/2023]
Abstract
BACKGROUND Acid pretreatment is a common strategy used to break down the hemicellulose component of the lignocellulosic biomass to release pentoses, and a subsequent enzymatic hydrolysis step is usually applied to release hexoses from the cellulose. The hydrolysate after pretreatment and enzymatic hydrolysis containing both hexoses and pentoses can then be used as substrates for biochemical production. However, the acid-pretreated liquor can also be directly used as the substrate for microbial fermentation, which has an acidic pH and contains inhibitory compounds generated during pretreatment. Although the natural ethanologenic bacterium Zymomonas mobilis can grow in a broad range of pH 3.5 ~ 7.5, cell growth and ethanol fermentation are still affected under acidic-pH conditions below pH 4.0. RESULTS In this study, adaptive laboratory evolution (ALE) strategy was applied to adapt Z. mobilis under acidic-pH conditions. Two mutant strains named 3.6M and 3.5M with enhanced acidic pH tolerance were selected and confirmed, of which 3.5M grew better than ZM4 but worse than 3.6M in acidic-pH conditions that is served as a reference strain between 3.6M and ZM4 to help unravel the acidic-pH tolerance mechanism. Mutant strains 3.5M and 3.6M exhibited 50 ~ 130% enhancement on growth rate, 4 ~ 9 h reduction on fermentation time to consume glucose, and 20 ~ 63% improvement on ethanol productivity than wild-type ZM4 at pH 3.8. Next-generation sequencing (NGS)-based whole-genome resequencing (WGR) and RNA-Seq technologies were applied to unravel the acidic-pH tolerance mechanism of mutant strains. WGR result indicated that compared to wild-type ZM4, 3.5M and 3.6M have seven and five single nucleotide polymorphisms (SNPs), respectively, among which four are shared in common. Additionally, RNA-Seq result showed that the upregulation of genes involved in glycolysis and the downregulation of flagellar and mobility related genes would help generate and redistribute cellular energy to resist acidic pH while keeping normal biological processes in Z. mobilis. Moreover, genes involved in RND efflux pump, ATP-binding cassette (ABC) transporter, proton consumption, and alkaline metabolite production were significantly upregulated in mutants under the acidic-pH condition compared with ZM4, which could help maintain the pH homeostasis in mutant strains for acidic-pH resistance. Furthermore, our results demonstrated that in mutant 3.6M, genes encoding F1F0 ATPase to pump excess protons out of cells were upregulated under pH 3.8 compared to pH 6.2. This difference might help mutant 3.6M manage acidic conditions better than ZM4 and 3.5M. A few gene targets were then selected for genetics study to explore their role in acidic pH tolerance, and our results demonstrated that the expression of two operons in the shuttle plasmids, ZMO0956-ZMO0958 encoding cytochrome bc1 complex and ZMO1428-ZMO1432 encoding RND efflux pump, could help Z. mobilis tolerate acidic-pH conditions. CONCLUSION An acidic-pH-tolerant mutant 3.6M obtained through this study can be used for commercial bioethanol production under acidic fermentation conditions. In addition, the molecular mechanism of acidic pH tolerance of Z. mobilis was further proposed, which can facilitate future research on rational design of synthetic microorganisms with enhanced tolerance against acidic-pH conditions. Moreover, the strategy developed in this study combining approaches of ALE, genome resequencing, RNA-Seq, and classical genetics study for mutant evolution and characterization can be applied in other industrial microorganisms.
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Affiliation(s)
- Qing Yang
- State Key Laboratory of Biocatalysis and Enzyme Engineering, Environmental Microbial Technology Center of Hubei Province and School of Life Sciences, Hubei University, Wuhan, 430062 China
| | - Yongfu Yang
- State Key Laboratory of Biocatalysis and Enzyme Engineering, Environmental Microbial Technology Center of Hubei Province and School of Life Sciences, Hubei University, Wuhan, 430062 China
| | - Ying Tang
- State Key Laboratory of Biocatalysis and Enzyme Engineering, Environmental Microbial Technology Center of Hubei Province and School of Life Sciences, Hubei University, Wuhan, 430062 China
| | - Xia Wang
- State Key Laboratory of Biocatalysis and Enzyme Engineering, Environmental Microbial Technology Center of Hubei Province and School of Life Sciences, Hubei University, Wuhan, 430062 China
| | - Yunhao Chen
- State Key Laboratory of Biocatalysis and Enzyme Engineering, Environmental Microbial Technology Center of Hubei Province and School of Life Sciences, Hubei University, Wuhan, 430062 China
| | - Wei Shen
- State Key Laboratory of Biocatalysis and Enzyme Engineering, Environmental Microbial Technology Center of Hubei Province and School of Life Sciences, Hubei University, Wuhan, 430062 China
| | - Yangyang Zhan
- State Key Laboratory of Biocatalysis and Enzyme Engineering, Environmental Microbial Technology Center of Hubei Province and School of Life Sciences, Hubei University, Wuhan, 430062 China
| | - Junjie Gao
- State Key Laboratory of Biocatalysis and Enzyme Engineering, Environmental Microbial Technology Center of Hubei Province and School 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
| | - Shouwen Chen
- State Key Laboratory of Biocatalysis and Enzyme Engineering, Environmental Microbial Technology Center of Hubei Province and School of Life Sciences, Hubei University, Wuhan, 430062 China
| | - Shihui Yang
- State Key Laboratory of Biocatalysis and Enzyme Engineering, Environmental Microbial Technology Center of Hubei Province and School of Life Sciences, Hubei University, Wuhan, 430062 China
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23
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Qiu M, Shen W, Yan X, He Q, Cai D, Chen S, Wei H, Knoshaug EP, Zhang M, Himmel ME, Yang S. Metabolic engineering of Zymomonas mobilis for anaerobic isobutanol production. BIOTECHNOLOGY FOR BIOFUELS 2020; 13:15. [PMID: 31998408 PMCID: PMC6982386 DOI: 10.1186/s13068-020-1654-x] [Citation(s) in RCA: 34] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/04/2019] [Accepted: 01/11/2020] [Indexed: 05/19/2023]
Abstract
BACKGROUND Biofuels and value-added biochemicals derived from renewable biomass via biochemical conversion have attracted considerable attention to meet global sustainable energy and environmental goals. Isobutanol is a four-carbon alcohol with many advantages that make it attractive as a fossil-fuel alternative. Zymomonas mobilis is a highly efficient, anaerobic, ethanologenic bacterium making it a promising industrial platform for use in a biorefinery. RESULTS In this study, the effect of isobutanol on Z. mobilis was investigated, and various isobutanol-producing recombinant strains were constructed. The results showed that the Z. mobilis parental strain was able to grow in the presence of isobutanol below 12 g/L while concentrations greater than 16 g/L inhibited cell growth. Integration of the heterologous gene encoding 2-ketoisovalerate decarboxylase such as kdcA from Lactococcus lactis is required for isobutanol production in Z. mobilis. Moreover, isobutanol production increased from nearly zero to 100-150 mg/L in recombinant strains containing the kdcA gene driven by the tetracycline-inducible promoter Ptet. In addition, we determined that overexpression of a heterologous als gene and two native genes (ilvC and ilvD) involved in valine metabolism in a recombinant Z. mobilis strain expressing kdcA can divert pyruvate from ethanol production to isobutanol biosynthesis. This engineering improved isobutanol production to above 1 g/L. Finally, recombinant strains containing both a synthetic operon, als-ilvC-ilvD, driven by Ptet and the kdcA gene driven by the constitutive strong promoter, Pgap, were determined to greatly enhance isobutanol production with a maximum titer about 4.0 g/L. Finally, isobutanol production was negatively affected by aeration with more isobutanol being produced in more poorly aerated flasks. CONCLUSIONS This study demonstrated that overexpression of kdcA in combination with a synthetic heterologous operon, als-ilvC-ilvD, is crucial for diverting pyruvate from ethanol production for enhanced isobutanol biosynthesis. Moreover, this study also provides a strategy for harnessing the valine metabolic pathway for future production of other pyruvate-derived biochemicals in Z. mobilis.
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Affiliation(s)
- Mengyue Qiu
- State Key Laboratory of Biocatalysis and Enzyme Engineering, Environmental Microbial Technology Center of Hubei Province, and School of Life Sciences, Hubei University, Wuhan, 430062 China
| | - Wei Shen
- State Key Laboratory of Biocatalysis and Enzyme Engineering, Environmental Microbial Technology Center of Hubei Province, and School of Life Sciences, Hubei University, Wuhan, 430062 China
| | - Xiongyin Yan
- State Key Laboratory of Biocatalysis and Enzyme Engineering, Environmental Microbial Technology Center of Hubei Province, and School of Life Sciences, Hubei University, Wuhan, 430062 China
| | - Qiaoning He
- State Key Laboratory of Biocatalysis and Enzyme Engineering, Environmental Microbial Technology Center of Hubei Province, and School of Life Sciences, Hubei University, Wuhan, 430062 China
| | - Dongbo Cai
- State Key Laboratory of Biocatalysis and Enzyme Engineering, Environmental Microbial Technology Center of Hubei Province, and School of Life Sciences, Hubei University, Wuhan, 430062 China
| | - Shouwen Chen
- State Key Laboratory of Biocatalysis and Enzyme Engineering, Environmental Microbial Technology Center of Hubei Province, and School of Life Sciences, Hubei University, Wuhan, 430062 China
| | - Hui Wei
- Biosciences Centers, National Renewable Energy Laboratory, Golden, CO 80401 USA
| | - Eric P. Knoshaug
- National Bioenergy Center, National Renewable Energy Laboratory, Golden, CO 80401 USA
| | - Min Zhang
- Biosciences Centers, National Renewable Energy Laboratory, Golden, CO 80401 USA
| | - Michael E. Himmel
- Biosciences Centers, National Renewable Energy Laboratory, Golden, CO 80401 USA
| | - Shihui Yang
- State Key Laboratory of Biocatalysis and Enzyme Engineering, Environmental Microbial Technology Center of Hubei Province, and School of Life Sciences, Hubei University, Wuhan, 430062 China
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24
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Zymomonas mobilis metabolism: Novel tools and targets for its rational engineering. Adv Microb Physiol 2020; 77:37-88. [PMID: 34756211 DOI: 10.1016/bs.ampbs.2020.08.001] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
Zymomonas mobilis is an α-proteobacterium that interests the biofuel industry due to its perfect ethanol fermentation yields. From its first description as a bacterial isolate in fermented alcoholic beverages to date, Z. mobilis has been rigorously studied in directions basic and applied. The Z. mobilis powerful Entner-Doudoroff glycolytic pathway has been the center of rigorous biochemical studies and, aside from ethanol, it has attracted interest in terms of high-added-value chemical manufacturing. Energetic balances and the effects of respiration have been explored in fundamental directions as also in applications pursuing strain enhancement and the utilization of alternative carbon sources. Metabolic modeling has addressed the optimization of the biochemical circuitry at various conditions of growth and/or substrate utilization; it has been also critical in predicting desirable end-product yields via flux redirection. Lastly, stress tolerance has received particular attention, since it directly determines biocatalytical performance at challenging bioreactor conditions. At a genetic level, advances in the genetic engineering of the organism have brought forth beneficial manipulations in the Z. mobilis gene pool, e.g., knock-outs, knock-ins and gene stacking, aiming to broaden the metabolic repertoire and increase robustness. Recent omic and expressional studies shed light on the genomic content of the most applied strains and reveal landscapes of activity manifested at ambient or reactor-based conditions. Studies such as those reviewed in this work, contribute to the understanding of the biology of Z. mobilis, enable insightful strain development, and pave the way for the transformation of Z. mobilis into a consummate organism for biomass conversion.
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25
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Yang Y, Rong Z, Song H, Yang X, Li M, Yang S. Identification and characterization of ethanol-inducible promoters of Zymomonas mobilis based on omics data and dual reporter-gene system. Biotechnol Appl Biochem 2019; 67:158-165. [PMID: 31626362 DOI: 10.1002/bab.1838] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/19/2019] [Accepted: 10/13/2019] [Indexed: 12/22/2022]
Abstract
Zymomonas mobilis is a model bacterial ethanologen and has been engineered to produce lignocellulosic biofuels and biochemicals such as 2,3-butanediol. We have previously identified promoters of different strengths using systems biology datasets and characterized them using the flow cytometry-based dual reporter-gene system. Here, we further demonstrated the capability of applying the dual reporter-gene system and omics datasets on discovering inducible promoters. Ten candidate ethanol-inducible promoters were identified through omics datasets mining and clustering. Using the dual reporter-gene system, these promoters were characterized under natural growth, ethanol stress, and ethanol-induced condition to investigate the transcriptional strength and ethanol inducibility. The results demonstrated that three promoters of P0405, P0435, and P0038 driving the expression of native genes of ZMO0405, ZMO0435, and ZMO0038, correspondingly, are potential ethanol-responsive promoters and may be growth related. This study not only identified and verified three ethanol-inducible promoters as biological parts, which can be used to synchronize the expression of heterologous pathway genes with the ethanol production process of Z. mobilis, but also demonstrated the power of combining omics datasets and dual reporter-gene system to identify biological parts for metabolic engineering and synthetic biology applications in Z. mobilis and related microorganisms.
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Affiliation(s)
- Yongfu Yang
- State Key Laboratory of Biocatalysis and Enzyme Engineering, Hubei Collaborative Innovation Center for Green Transformation of Bio-resources, Environmental Microbial Technology Center of Hubei Province, and School of Life Sciences, Hubei University, Wuhan, China
| | - Ziyue Rong
- State Key Laboratory of Biocatalysis and Enzyme Engineering, Hubei Collaborative Innovation Center for Green Transformation of Bio-resources, Environmental Microbial Technology Center of Hubei Province, and School of Life Sciences, Hubei University, Wuhan, China
| | - Haoyue Song
- State Key Laboratory of Biocatalysis and Enzyme Engineering, Hubei Collaborative Innovation Center for Green Transformation of Bio-resources, Environmental Microbial Technology Center of Hubei Province, and School of Life Sciences, Hubei University, Wuhan, China
| | - Xiuxiu Yang
- State Key Laboratory of Biocatalysis and Enzyme Engineering, Hubei Collaborative Innovation Center for Green Transformation of Bio-resources, Environmental Microbial Technology Center of Hubei Province, and School of Life Sciences, Hubei University, Wuhan, China
| | - Mian Li
- Zhejiang Huakang Pharmaceutical Co., Ltd., Kaihua County, Zhejiang, China
| | - Shihui Yang
- State Key Laboratory of Biocatalysis and Enzyme Engineering, Hubei Collaborative Innovation Center for Green Transformation of Bio-resources, Environmental Microbial Technology Center of Hubei Province, and School of Life Sciences, Hubei University, Wuhan, China
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26
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Discovery and Characterization of Native Deinococcus radiodurans Promoters for Tunable Gene Expression. Appl Environ Microbiol 2019; 85:AEM.01356-19. [PMID: 31471304 DOI: 10.1128/aem.01356-19] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2019] [Accepted: 08/26/2019] [Indexed: 01/28/2023] Open
Abstract
The potential utilization of extremophiles as a robust chassis for metabolic engineering applications has prompted interest in the use of Deinococcus radiodurans for bioremediation efforts, but current applications are limited by the lack of availability of genetic tools, such as promoters. In this study, we used a combined computational and experimental approach to identify and screen 30 predicted promoters for expression in D. radiodurans using a fluorescent reporter assay. The top eight candidates were further characterized, compared to currently available promoters, and optimized for engineering through minimization for use in D. radiodurans Of these top eight, two promoter regions, PDR_1261 and PrpmB, were stronger and more consistent than the most widely used promoter sequence in D. radiodurans, PgroES Furthermore, half of the top eight promoters could be minimized by at least 20% (to obtain final sequences that are approximately 24 to 177 bp), and several of the putative promoters either showed activity in Escherichia coli or were D. radiodurans specific, broadening the use of the promoters for various applications. Overall, this work introduces a suite of novel, well-characterized promoters for protein production and metabolic engineering in D. radiodurans IMPORTANCE The tolerance of the extremophile, Deinococcus radiodurans, to numerous oxidative stresses makes it ideal for bioremediation applications, but many of the tools necessary for metabolic engineering are lacking in this organism compared to model bacteria. Although native and engineered promoters have been used to drive gene expression for protein production in D. radiodurans, very few have been well characterized. Informed by bioinformatics, this study expands the repertoire of well-characterized promoters for D. radiodurans via thorough characterization of eight putative promoters with various strengths. These results will help facilitate tunable gene expression, since these promoters demonstrate strong and consistent performance compared to the current standard, PgroES This study also provides a methodology for high-throughput promoter identification and characterization using fluorescence in D. radiodurans The promoters identified in this study will facilitate metabolic engineering of D. radiodurans and enable its use in biotechnological applications ranging from bioremediation to synthesis of commodity chemicals.
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27
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Li Y, Zhai R, Jiang X, Chen X, Yuan X, Liu Z, Jin M. Boosting Ethanol Productivity of Zymomonas mobilis 8b in Enzymatic Hydrolysate of Dilute Acid and Ammonia Pretreated Corn Stover Through Medium Optimization, High Cell Density Fermentation and Cell Recycling. Front Microbiol 2019; 10:2316. [PMID: 31636624 PMCID: PMC6787488 DOI: 10.3389/fmicb.2019.02316] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/03/2019] [Accepted: 09/23/2019] [Indexed: 12/19/2022] Open
Abstract
The presence of toxic degradation products in lignocellulosic hydrolysate typically reduced fermentation rates and xylose consumption rate, resulting in a decreased ethanol productivity. In the present study, Zymomonas mobilis 8b was investigated for high cell density fermentation with cell recycling to improve the ethanol productivity in lignocellulosic hydrolysate. The fermentation performances of Z. mobilis 8b at various conditions were first studied in yeast extract-tryptone medium. It was found that nutrient level was essential for glucose and xylose co-fermentation by Z. mobilis 8b and high cell density fermentation with cell recycling worked well in yeast extract-tryptone medium for 6 rounds fermentation. Z. mobilis 8b was then studied in enzymatic hydrolysates derived from dilute acid (DA) pretreated corn stover (CS) and ammonia pretreated CS for high cell density fermentation with cell recycling. Ethanol productivity obtained was around three times higher compared to traditional fermentation. Ethanol titer and metabolic yield were also enhanced with high cell density fermentation. Z. mobilis 8b cells showed high recyclability in ammonia pretreated CS hydrolysate.
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Affiliation(s)
- Ying Li
- School of Environmental and Biological Engineering, Nanjing University of Science and Technology, Nanjing, China
| | - Rui Zhai
- School of Environmental and Biological Engineering, Nanjing University of Science and Technology, Nanjing, China
| | - Xiaoxiao Jiang
- School of Environmental and Biological Engineering, Nanjing University of Science and Technology, Nanjing, China
| | - Xiangxue Chen
- School of Environmental and Biological Engineering, Nanjing University of Science and Technology, Nanjing, China
| | - Xinchuan Yuan
- School of Environmental and Biological Engineering, Nanjing University of Science and Technology, Nanjing, China
| | - Zhihua Liu
- Department of Plant Pathology and Microbiology, College of Agriculture and Life Sciences, Texas A&M University, College Station, TX, United States
| | - Mingjie Jin
- School of Environmental and Biological Engineering, Nanjing University of Science and Technology, Nanjing, China
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28
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Shen W, Zhang J, Geng B, Qiu M, Hu M, Yang Q, Bao W, Xiao Y, Zheng Y, Peng W, Zhang G, Ma L, Yang S. Establishment and application of a CRISPR-Cas12a assisted genome-editing system in Zymomonas mobilis. Microb Cell Fact 2019; 18:162. [PMID: 31581942 PMCID: PMC6777028 DOI: 10.1186/s12934-019-1219-5] [Citation(s) in RCA: 37] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2019] [Accepted: 09/26/2019] [Indexed: 12/27/2022] Open
Abstract
BACKGROUND Efficient and convenient genome-editing toolkits can expedite genomic research and strain improvement for desirable phenotypes. Zymomonas mobilis is a highly efficient ethanol-producing bacterium with a small genome size and desirable industrial characteristics, which makes it a promising chassis for biorefinery and synthetic biology studies. While classical techniques for genetic manipulation are available for Z. mobilis, efficient genetic engineering toolkits enabling rapidly systematic and high-throughput genome editing in Z. mobilis are still lacking. RESULTS Using Cas12a (Cpf1) from Francisella novicida, a recombinant strain with inducible cas12a expression for genome editing was constructed in Z. mobilis ZM4, which can be used to mediate RNA-guided DNA cleavage at targeted genomic loci. gRNAs were then designed targeting the replicons of native plasmids of ZM4 with about 100% curing efficiency for three native plasmids. In addition, CRISPR-Cas12a recombineering was used to promote gene deletion and insertion in one step efficiently and precisely with efficiency up to 90%. Combined with single-stranded DNA (ssDNA), CRISPR-Cas12a system was also applied to introduce minor nucleotide modification precisely into the genome with high fidelity. Furthermore, the CRISPR-Cas12a system was employed to introduce a heterologous lactate dehydrogenase into Z. mobilis with a recombinant lactate-producing strain constructed. CONCLUSIONS This study applied CRISPR-Cas12a in Z. mobilis and established a genome editing tool for efficient and convenient genome engineering in Z. mobilis including plasmid curing, gene deletion and insertion, as well as nucleotide substitution, which can also be employed for metabolic engineering to help divert the carbon flux from ethanol production to other products such as lactate demonstrated in this work. The CRISPR-Cas12a system established in this study thus provides a versatile and powerful genome-editing tool in Z. mobilis for functional genomic research, strain improvement, as well as synthetic microbial chassis development for economic biochemical production.
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Affiliation(s)
- Wei Shen
- State Key Laboratory of Biocatalysis and Enzyme Engineering, Environmental Microbial Technology Center of Hubei Province and School of Life Sciences, Hubei University, Wuhan, 430062 China
| | - Jun Zhang
- State Key Laboratory of Biocatalysis and Enzyme Engineering, Environmental Microbial Technology Center of Hubei Province and School of Life Sciences, Hubei University, Wuhan, 430062 China
| | - Binan Geng
- State Key Laboratory of Biocatalysis and Enzyme Engineering, Environmental Microbial Technology Center of Hubei Province and School of Life Sciences, Hubei University, Wuhan, 430062 China
| | - Mengyue Qiu
- State Key Laboratory of Biocatalysis and Enzyme Engineering, Environmental Microbial Technology Center of Hubei Province and School of Life Sciences, Hubei University, Wuhan, 430062 China
| | - Mimi Hu
- State Key Laboratory of Biocatalysis and Enzyme Engineering, Environmental Microbial Technology Center of Hubei Province and School of Life Sciences, Hubei University, Wuhan, 430062 China
| | - Qing Yang
- State Key Laboratory of Biocatalysis and Enzyme Engineering, Environmental Microbial Technology Center of Hubei Province and School of Life Sciences, Hubei University, Wuhan, 430062 China
| | - Weiwei Bao
- State Key Laboratory of Biocatalysis and Enzyme Engineering, Environmental Microbial Technology Center of Hubei Province and School of Life Sciences, Hubei University, Wuhan, 430062 China
| | - Yubei Xiao
- State Key Laboratory of Biocatalysis and Enzyme Engineering, Environmental Microbial Technology Center of Hubei Province and School of Life Sciences, Hubei University, Wuhan, 430062 China
| | - Yanli Zheng
- State Key Laboratory of Biocatalysis and Enzyme Engineering, Environmental Microbial Technology Center of Hubei Province and School of Life Sciences, Hubei University, Wuhan, 430062 China
| | - Wenfang Peng
- State Key Laboratory of Biocatalysis and Enzyme Engineering, Environmental Microbial Technology Center of Hubei Province and School of Life Sciences, Hubei University, Wuhan, 430062 China
| | - Guimin Zhang
- State Key Laboratory of Biocatalysis and Enzyme Engineering, Environmental Microbial Technology Center of Hubei Province and School of Life Sciences, Hubei University, Wuhan, 430062 China
| | - Lixin Ma
- State Key Laboratory of Biocatalysis and Enzyme Engineering, Environmental Microbial Technology Center of Hubei Province and School of Life Sciences, Hubei University, Wuhan, 430062 China
| | - Shihui Yang
- State Key Laboratory of Biocatalysis and Enzyme Engineering, Environmental Microbial Technology Center of Hubei Province and School of Life Sciences, Hubei University, Wuhan, 430062 China
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