1
|
Lu P, Gao T, Bai R, Yang J, Xu Y, Chu W, Jiang K, Zhang J, Xu F, Zhao H. Regulation of carbon flux and NADH/NAD + supply to enhance 2,3-butanediol production in Enterobacter aerogenes. J Biotechnol 2022; 358:67-75. [PMID: 36087783 DOI: 10.1016/j.jbiotec.2022.09.001] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/12/2022] [Revised: 08/23/2022] [Accepted: 09/05/2022] [Indexed: 10/31/2022]
Abstract
As a valuable platform chemical, 2,3-Butanediol (2,3-BDO) has a variety of industrial applications, and its microbial production is particularly attractive as an alternative to petroleum-based production. In this study, the regulation of intracellular carbon flux and NADH/NAD+ was used to increase the 2,3-BDO production of Enterobacter aerogenes. The genes encoding lactate dehydrogenase (ldh) and pyruvate formate lyase (pfl) were disrupted using the λ-Red recombination method and CRISPR-Cas9 to reduce the production of several byproducts and the consumption of NADH. Knockout of ldh or pfl increased intracellular NADH/NAD+ by 111 % and 113 %, respectively. Moreover, two important genes in the 2,3-BDO biosynthesis pathway, acetolactate synthase (budB) and acetoin reductase (budC), were overexpressed in E. aerogenes to further amply the metabolic flux toward 2,3-BDO production. And the overexpression of budB or budC increased intracellular NADH/NAD+ by 46 % and 57 %, respectively. In shake-flask cultivation with sucrose as carbon source, the 2,3-BDO titer of the IAM1183-LPBC was 3.55 times that of the wild type. In the 5-L fermenter, the maximal 2,3-BDO production produced by the IAM1183-LPBC was 2.88 times that of the original strain. This work offers new ideas for promoting the biosynthesis of 2,3-BDO for industrial applications.
Collapse
Affiliation(s)
- Ping Lu
- Zhejiang Province Key Laboratory of Plant Secondary Metabolism and Regulation, College of Life Sciences and Medicine, Zhejiang Sci-Tech University, Hangzhou 310018, China
| | - Ting Gao
- Zhejiang Province Key Laboratory of Plant Secondary Metabolism and Regulation, College of Life Sciences and Medicine, Zhejiang Sci-Tech University, Hangzhou 310018, China
| | - Ruoxuan Bai
- Zhejiang Province Key Laboratory of Plant Secondary Metabolism and Regulation, College of Life Sciences and Medicine, Zhejiang Sci-Tech University, Hangzhou 310018, China
| | - Jiayao Yang
- Zhejiang Province Key Laboratory of Plant Secondary Metabolism and Regulation, College of Life Sciences and Medicine, Zhejiang Sci-Tech University, Hangzhou 310018, China
| | - Yudong Xu
- Zhejiang Province Key Laboratory of Plant Secondary Metabolism and Regulation, College of Life Sciences and Medicine, Zhejiang Sci-Tech University, Hangzhou 310018, China
| | - Wanying Chu
- Zhejiang Province Key Laboratory of Plant Secondary Metabolism and Regulation, College of Life Sciences and Medicine, Zhejiang Sci-Tech University, Hangzhou 310018, China
| | - Ke Jiang
- Zhejiang Province Key Laboratory of Plant Secondary Metabolism and Regulation, College of Life Sciences and Medicine, Zhejiang Sci-Tech University, Hangzhou 310018, China
| | - Jingya Zhang
- Zhejiang Province Key Laboratory of Plant Secondary Metabolism and Regulation, College of Life Sciences and Medicine, Zhejiang Sci-Tech University, Hangzhou 310018, China
| | - Fangxu Xu
- Liaoning Province Key Laboratory of Cordyceps Militaris with Functional Value, Experimental Teaching Center, Shenyang Normal University, Shenyang 110034, China
| | - Hongxin Zhao
- Zhejiang Province Key Laboratory of Plant Secondary Metabolism and Regulation, College of Life Sciences and Medicine, Zhejiang Sci-Tech University, Hangzhou 310018, China.
| |
Collapse
|
2
|
Jayachandran V, Basak N, De Philippis R, Adessi A. Novel strategies towards efficient molecular biohydrogen production by dark fermentative mechanism: present progress and future perspective. Bioprocess Biosyst Eng 2022; 45:1595-1624. [PMID: 35713786 DOI: 10.1007/s00449-022-02738-4] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/28/2022] [Accepted: 05/27/2022] [Indexed: 01/05/2023]
Abstract
In the scenario of alarming increase in greenhouse and toxic gas emissions from the burning of conventional fuels, it is high time that the population drifts towards alternative fuel usage to obviate pollution. Hydrogen is an environment-friendly biofuel with high energy content. Several production methods exist to produce hydrogen, but the least energy intensive processes are the fermentative biohydrogen techniques. Dark fermentative biohydrogen production (DFBHP) is a value-added, less energy-consuming process to generate biohydrogen. In this process, biohydrogen can be produced from sugars as well as complex substrates that are generally considered as organic waste. Yet, the process is constrained by many factors such as low hydrogen yield, incomplete conversion of substrates, accumulation of volatile fatty acids which lead to the drop of the system pH resulting in hindered growth and hydrogen production by the bacteria. To circumvent these drawbacks, researchers have come up with several strategies that improve the yield of DFBHP process. These strategies can be classified as preliminary methodologies concerned with the process optimization and the latter that deals with pretreatment of substrate and seed sludge, bioaugmentation, co-culture of bacteria, supplementation of additives, bioreactor design considerations, metabolic engineering, nanotechnology, immobilization of bacteria, etc. This review sums up some of the improvement techniques that profoundly enhance the biohydrogen productivity in a DFBHP process.
Collapse
Affiliation(s)
- Varsha Jayachandran
- Department of Biotechnology, Dr. B. R. Ambedkar National Institute of Technology, Jalandhar, 144 027, Punjab, India
| | - Nitai Basak
- Department of Biotechnology, Dr. B. R. Ambedkar National Institute of Technology, Jalandhar, 144 027, Punjab, India.
| | - Roberto De Philippis
- Department of Agriculture, Food, Environment and Forestry, Florence University, Florence, Italy
| | - Alessandra Adessi
- Department of Agriculture, Food, Environment and Forestry, Florence University, Florence, Italy
| |
Collapse
|
3
|
Wu Y, Chu W, Yang J, Xu Y, Shen Q, Yang H, Xu F, Liu Y, Lu P, Jiang K, Zhao H. Metabolic Engineering of Enterobacter aerogenes for Improved 2,3-Butanediol Production by Manipulating NADH Levels and Overexpressing the Small RNA RyhB. Front Microbiol 2021; 12:754306. [PMID: 34691005 PMCID: PMC8531500 DOI: 10.3389/fmicb.2021.754306] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/06/2021] [Accepted: 09/16/2021] [Indexed: 11/29/2022] Open
Abstract
Biotechnological production of 2,3-butanediol (2,3-BD), a versatile platform bio-chemical and a potential biofuel, is limited due to by-product toxicity. In this study, we aimed to redirect the metabolic flux toward 2,3-BD in Enterobacter aerogenes (E. aerogenes) by increasing the intracellular NADH pool. Increasing the NADH/NAD+ ratio by knocking out the NADH dehydrogenase genes (nuoC/nuoD) enhanced 2,3-BD production by up to 67% compared with wild-type E. aerogenes. When lactate dehydrogenase (ldh) was knocked out, the yield of 2,3-BD was increased by 71.2% compared to the wild type. Metabolic flux analysis revealed that upregulated expression of the sRNA RyhB led to a noteworthy shift in metabolism. The 2,3-BD titer of the best mutant Ea-2 was almost seven times higher than that of the parent strain in a 5-L fermenter. In this study, an effective metabolic engineering strategy for improved 2,3-BD production was implemented by increasing the NADH/NAD+ ratio and blocking competing pathways.
Collapse
Affiliation(s)
- Yan Wu
- Zhejiang Province Key Laboratory of Plant Secondary Metabolism and Regulation, College of Life Sciences and Medicine, Zhejiang Sci-Tech University, Hangzhou, China
- Key Laboratory of Urban Agriculture by Ministry of Agriculture of China, School of Agriculture and Biology, Shanghai Jiao Tong University, Shanghai, China
| | - Wanying Chu
- Zhejiang Province Key Laboratory of Plant Secondary Metabolism and Regulation, College of Life Sciences and Medicine, Zhejiang Sci-Tech University, Hangzhou, China
| | - Jiayao Yang
- Zhejiang Province Key Laboratory of Plant Secondary Metabolism and Regulation, College of Life Sciences and Medicine, Zhejiang Sci-Tech University, Hangzhou, China
| | - Yudong Xu
- Zhejiang Province Key Laboratory of Plant Secondary Metabolism and Regulation, College of Life Sciences and Medicine, Zhejiang Sci-Tech University, Hangzhou, China
| | - Qi Shen
- Zhejiang Province Key Laboratory of Plant Secondary Metabolism and Regulation, College of Life Sciences and Medicine, Zhejiang Sci-Tech University, Hangzhou, China
| | - Haoning Yang
- Department of Bioengineering, Liaoning Technical University, Fuxin, China
| | - Fangxu Xu
- Experimental Teaching Center, College of Life Science, Shenyang Normal University, Shenyang, China
| | - Yefei Liu
- Experimental Teaching Center, College of Life Science, Shenyang Normal University, Shenyang, China
| | - Ping Lu
- Zhejiang Province Key Laboratory of Plant Secondary Metabolism and Regulation, College of Life Sciences and Medicine, Zhejiang Sci-Tech University, Hangzhou, China
| | - Ke Jiang
- Zhejiang Province Key Laboratory of Plant Secondary Metabolism and Regulation, College of Life Sciences and Medicine, Zhejiang Sci-Tech University, Hangzhou, China
| | - Hongxin Zhao
- Zhejiang Province Key Laboratory of Plant Secondary Metabolism and Regulation, College of Life Sciences and Medicine, Zhejiang Sci-Tech University, Hangzhou, China
| |
Collapse
|
4
|
Chu W, Jiang K, Lu P, Xu Y, Yang J, Wei X, Li L, Liu S, Wu Y, Wang S, Zhao H, Zhao H. Metabolic regulation and optimization of oxygen supply enhance the 2,3-butanediol yield of the novel Klebsiella sp. isolate FSoil 024. Biotechnol J 2021; 16:e2100279. [PMID: 34390606 DOI: 10.1002/biot.202100279] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/28/2021] [Revised: 08/11/2021] [Accepted: 08/12/2021] [Indexed: 11/05/2022]
Abstract
BACKGROUND Biogenic 2,3-butanediol (2,3-BDO) is a high-value-added compound that can be used as a liquid fuel and a platform chemical. Bioproduction of 2,3-BDO is an environmentally friendly choice. METHOD AND RESULTS Three recombinant derivatives of the novel Klebsiella sp. isolate FSoil 024 (WT) were constructed via different strategies including deletion of lactate dehydrogenase by λ-Red homologous recombination technology, overexpression of the small-noncoding RNA RyhB and a combination of both. The 2,3-BDO productivity of the mutants increased by 61.3-79%, and WT-Δldh/ryhB displayed the highest 2,3-BDO yield of 42.36 mM after 24 h of shake-flask fermentation. Glucose was shown as the best carbon source for 2,3-BDO production by WT-Δldh/ryhB. In addition, higher oxygenation was favorable for ideal product synthesis. The maximal 2,3-BDO yield of WT and WT-Δldh/ryhB were increased by 23.3 and 52.5% respectively compared to the control group in the presence of 70% oxygen (V:V' = O2 :(O2 +N2 )). CONCLUSION AND IMPLICATIONS According to the present study, deletion of lactate dehydrogenase, RyhB overexpression and manipulation of oxygen supply showed great impacts on cell growth, 2,3-BDO productivity and cellular metabolism of the novel isolated strain Klebsiella sp. FSoil 024. This work would also provide insights for promoting 2,3-BDO biosynthesis for industrial applications. This article is protected by copyright. All rights reserved.
Collapse
Affiliation(s)
- Wanying Chu
- Zhejiang Province Key Laboratory of Plant Secondary Metabolism and Regulation, College of Life Sciences and Medicine, Zhejiang Sci-Tech University, Hangzhou, China
| | - Ke Jiang
- Zhejiang Province Key Laboratory of Plant Secondary Metabolism and Regulation, College of Life Sciences and Medicine, Zhejiang Sci-Tech University, Hangzhou, China
| | - Ping Lu
- Zhejiang Province Key Laboratory of Plant Secondary Metabolism and Regulation, College of Life Sciences and Medicine, Zhejiang Sci-Tech University, Hangzhou, China
| | - Yudong Xu
- Zhejiang Province Key Laboratory of Plant Secondary Metabolism and Regulation, College of Life Sciences and Medicine, Zhejiang Sci-Tech University, Hangzhou, China
| | - Jiayao Yang
- Zhejiang Province Key Laboratory of Plant Secondary Metabolism and Regulation, College of Life Sciences and Medicine, Zhejiang Sci-Tech University, Hangzhou, China
| | - Xuan Wei
- Zhejiang Province Key Laboratory of Plant Secondary Metabolism and Regulation, College of Life Sciences and Medicine, Zhejiang Sci-Tech University, Hangzhou, China
| | - Li Li
- Zhejiang Province Key Laboratory of Plant Secondary Metabolism and Regulation, College of Life Sciences and Medicine, Zhejiang Sci-Tech University, Hangzhou, China
| | - Shuxin Liu
- Zhejiang Province Key Laboratory of Plant Secondary Metabolism and Regulation, College of Life Sciences and Medicine, Zhejiang Sci-Tech University, Hangzhou, China
| | - Yan Wu
- Zhejiang Province Key Laboratory of Plant Secondary Metabolism and Regulation, College of Life Sciences and Medicine, Zhejiang Sci-Tech University, Hangzhou, China
| | - Shenghou Wang
- Experimental Teaching Center, College of Life Science, Shenyang Normal University, Shenyang, China
| | - Hongxin Zhao
- Zhejiang Province Key Laboratory of Plant Secondary Metabolism and Regulation, College of Life Sciences and Medicine, Zhejiang Sci-Tech University, Hangzhou, China
| | - Hongxin Zhao
- Zhejiang Province Key Laboratory of Plant Secondary Metabolism and Regulation, College of Life Sciences and Medicine, Zhejiang Sci-Tech University, Hangzhou, China
| |
Collapse
|
5
|
Zhang Q, You S, Li Y, Qu X, Jiang H. Enhanced biohydrogen production from cotton stalk hydrolysate of Enterobacter cloacae WL1318 by overexpression of the formate hydrogen lyase activator gene. BIOTECHNOLOGY FOR BIOFUELS 2020; 13:94. [PMID: 32489423 PMCID: PMC7245044 DOI: 10.1186/s13068-020-01733-9] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/18/2020] [Accepted: 05/16/2020] [Indexed: 05/29/2023]
Abstract
BACKGROUND Biohydrogen production from lignocellulose has become an important hydrogen production method due to its diversity, renewability, and cheapness. Overexpression of the formate hydrogen lyase activator (fhlA) gene is a promising tactic for enhancement of hydrogen production in facultative anaerobic Enterobacter. As a species of Enterobacter, Enterobacter cloacae was reported as a highly efficient hydrogen-producing bacterium. However, little work has been reported in terms of cloning and expressing the fhlA gene in E. cloacae for lignocellulose-based hydrogen production. RESULTS In this study, the formate hydrogen lyase activator (fhlA) gene was cloned and overexpressed in Enterobacter cloacae WL1318. We found that the recombinant strain significantly enhanced cumulative hydrogen production by 188% following fermentation of cotton stalk hydrolysate for 24 h, and maintained improved production above 30% throughout the fermentation process compared to the wild strain. Accordingly, overexpression of the fhlA gene resulted in an enhanced hydrogen production potential (P) and maximum hydrogen production rate (R m), as well as a shortened lag phase time (λ) for the recombinant strain. Additionally, the recombinant strain also displayed improved glucose (12%) and xylose (3.4%) consumption and hydrogen yield Y(H2/S) (37.0%) compared to the wild strain. Moreover, the metabolites and specific enzyme profiles demonstrated that reduced flux in the competitive branch, including succinic, acetic, and lactic acids, and ethanol generation, coupled with increased flux in the pyruvate node and formate splitting branch, benefited hydrogen synthesis. CONCLUSIONS The results conclusively prove that overexpression of fhlA gene in E. cloacae WL1318 can effectively enhance the hydrogen production from cotton stalk hydrolysate, and reduce the metabolic flux in the competitive branch. It is the first attempt to engineer the fhlA gene in the hydrogen-producing bacterium E. cloacae. This work provides a highly efficient engineered bacterium for biohydrogen production from fermentation of lignocellulosic hydrolysate in the future.
Collapse
Affiliation(s)
- Qin Zhang
- College of Biological and Chemical Engineering, Anhui Polytechnic University, Wuhu, 241000 Anhui China
| | - Shaolin You
- College of Biological and Chemical Engineering, Anhui Polytechnic University, Wuhu, 241000 Anhui China
| | - Yanbin Li
- College of Biological and Chemical Engineering, Anhui Polytechnic University, Wuhu, 241000 Anhui China
| | - Xiaowei Qu
- College of Life Science, Tarim University, Alaer, 843300 Xinjiang China
| | - Hui Jiang
- College of Life Science, Tarim University, Alaer, 843300 Xinjiang China
| |
Collapse
|
6
|
Evaluating the Pathway for Co-fermentation of Glucose and Xylose for Enhanced Bioethanol Production Using Flux Balance Analysis. BIOTECHNOL BIOPROC E 2019. [DOI: 10.1007/s12257-019-0026-5] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023]
|
7
|
Bioprocess engineering for biohythane production from low-grade waste biomass: technical challenges towards scale up. Curr Opin Biotechnol 2018; 50:25-31. [DOI: 10.1016/j.copbio.2017.08.014] [Citation(s) in RCA: 46] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/14/2017] [Revised: 08/21/2017] [Accepted: 08/22/2017] [Indexed: 01/05/2023]
|
8
|
Wu Y, Hao Y, Wei X, Shen Q, Ding X, Wang L, Zhao H, Lu Y. Impairment of NADH dehydrogenase and regulation of anaerobic metabolism by the small RNA RyhB and NadE for improved biohydrogen production in Enterobacter aerogenes. BIOTECHNOLOGY FOR BIOFUELS 2017; 10:248. [PMID: 29093752 PMCID: PMC5663082 DOI: 10.1186/s13068-017-0938-2] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/17/2017] [Accepted: 10/19/2017] [Indexed: 05/27/2023]
Abstract
BACKGROUND Enterobacter aerogenes is a facultative anaerobe and is one of the most widely studied bacterial strains because of its ability to use a variety of substrates, to produce hydrogen at a high rate, and its high growth rate during dark fermentation. However, the rate of hydrogen production has not been optimized. In this present study, three strategies to improve hydrogen production in E. aerogenes, namely the disruption of nuoCDE, overexpression of the small RNA RyhB and of NadE to regulate global anaerobic metabolism, and the redistribution of metabolic flux. The goal of this study was to clarify the effect of nuoCDE, RyhB, and NadE on hydrogen production and how the perturbation of NADH influences the yield of hydrogen gas from E. aerogenes. RESULTS NADH dehydrogenase activity was impaired by knocking out nuoCD or nuoCDE in E. aerogenes IAM1183 using the CRISPR-Cas9 system to explore the consequent effect on hydrogen production. The hydrogen yields from IAM1183-CD(∆nuoC/∆nuoD) and IAM1183-CDE (∆nuoC/∆nuoD/∆nuoE) increased, respectively, by 24.5 and 45.6% in batch culture (100 mL serum bottles). The hydrogen produced via the NADH pathway increased significantly in IAM1183-CDE, suggesting that nuoE plays an important role in regulating NADH concentration in E. aerogenes. Batch-cultivating experiments showed that by the overexpression of NadE (N), the hydrogen yields of IAM1183/N, IAM1183-CD/N, and IAM1183-CDE/N increased 1.06-, 1.35-, and 1.55-folds, respectively, compared with IAM1183. Particularly worth mentioning is that the strain IAM118-CDE/N reached 2.28 mol in H2 yield, per mole of glucose consumed. IAN1183/R, IAM1183-CD/R, and IAM1183-CDE/R showed increasing H2 yields in batch culture. Metabolic flux analysis indicated that increased expression of RyhB led to a significant shift in metabolic patterns. We further investigated IAM1183-CDE/N, which had the best hydrogen-producing traits, as a potential candidate for industry applications using a 5-L fermenter; hydrogen production reached up to 1.95 times greater than that measured for IAM1183. CONCLUSIONS Knockout of nuoCD or nuoCDE and the overexpression of nadE in E. aerogenes resulted in a redistribution of metabolic flux and improved the hydrogen yield. Overexpression of RyhB had an significant change on the hydrogen production via NADH pathway. A combination of strategies would be a novel approach for developing a more economic and efficient bioprocess for hydrogen production in E. aerogenes. Finally, the latest CRISPR-Cas9 technology was successful for editing genes in E. aerogenes to develop our engineered strain for hydrogen production.
Collapse
Affiliation(s)
- Yan Wu
- Zhejiang Province Key Laboratory of Plant Secondary Metabolism and Regulation, College of Life Sciences, Zhejiang Sci-Tech University, Hangzhou, 310018 China
| | - Yaqiao Hao
- Zhejiang Province Key Laboratory of Plant Secondary Metabolism and Regulation, College of Life Sciences, Zhejiang Sci-Tech University, Hangzhou, 310018 China
- College of Life Science, Shenyang Normal University, Shenyang, 110034 China
| | - Xuan Wei
- Zhejiang Province Key Laboratory of Plant Secondary Metabolism and Regulation, College of Life Sciences, Zhejiang Sci-Tech University, Hangzhou, 310018 China
- College of Life Science, Shenyang Normal University, Shenyang, 110034 China
| | - Qi Shen
- Zhejiang Province Key Laboratory of Plant Secondary Metabolism and Regulation, College of Life Sciences, Zhejiang Sci-Tech University, Hangzhou, 310018 China
| | - Xuanwei Ding
- Zhejiang Province Key Laboratory of Plant Secondary Metabolism and Regulation, College of Life Sciences, Zhejiang Sci-Tech University, Hangzhou, 310018 China
- Key Lab of Industrial Biocatalysis, Ministry of Education, Department of Chemical Engineering, Tsinghua University, Beijing, 100084 China
- Department of Chemical Engineering, Institute of Biochemical Engineering, Tsinghua University, Beijing, 100084 China
- College of Life Science, Shenyang Normal University, Shenyang, 110034 China
| | - Liyan Wang
- Department of Chemical Engineering, Institute of Biochemical Engineering, Tsinghua University, Beijing, 100084 China
| | - Hongxin Zhao
- Zhejiang Province Key Laboratory of Plant Secondary Metabolism and Regulation, College of Life Sciences, Zhejiang Sci-Tech University, Hangzhou, 310018 China
| | - Yuan Lu
- Key Lab of Industrial Biocatalysis, Ministry of Education, Department of Chemical Engineering, Tsinghua University, Beijing, 100084 China
- Department of Chemical Engineering, Institute of Biochemical Engineering, Tsinghua University, Beijing, 100084 China
| |
Collapse
|
9
|
Perturbation of formate pathway and NADH pathway acting on the biohydrogen production. Sci Rep 2017; 7:9587. [PMID: 28852065 PMCID: PMC5575262 DOI: 10.1038/s41598-017-10191-7] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/13/2017] [Accepted: 08/03/2017] [Indexed: 11/21/2022] Open
Abstract
The formate pathway and NADH pathway as two common hydrogen-producing metabolic pathways have been well characterized to understand and improve biohydrogen production. These two pathways have been thought to be separate and have been independently investigated. However, in this study, perturbation of genes (hycA, fdhF, fhlA, ldhA, nuoB, hybO, fdh1, narP, and ppk) in Enterobacter aerogenes related to the formate pathway or NADH pathway revealed that these two pathways affected each other. Further metabolic analysis suggested that a linear relationship existed between the relative change of hydrogen yield in the formate pathway or NADH pathway and the relative change of NADH yield or ATP yield. Thus, this finding provides new insight into the role of cellular reducing power and energy level in the hydrogen metabolism. It also establishes a rationale for improving hydrogen production from a global perspective.
Collapse
|
10
|
Contributory roles of two l-lactate dehydrogenases for l-lactic acid production in thermotolerant Bacillus coagulans. Sci Rep 2016; 6:37916. [PMID: 27885267 PMCID: PMC5122838 DOI: 10.1038/srep37916] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/09/2015] [Accepted: 11/04/2016] [Indexed: 02/06/2023] Open
Abstract
Thermotolerant Bacillus coagulans is considered to be a more promising producer for bio-chemicals, due to its capacity to withstand harsh conditions. Two L-lactate dehydrogenase (LDH) encoding genes (ldhL1 and ldhL2) and one D-LDH encoding gene (ldhD) were annotated from the B. coagulans DSM1 genome. Transcriptional analysis revealed that the expression of ldhL2 was undetectable while the ldhL1 transcription level was much higher than that of ldhD at all growth phases. Deletion of the ldhL2 gene revealed no difference in fermentation profile compared to the wild-type strain, while ldhL1 single deletion or ldhL1ldhL2 double deletion completely blocked L-lactic acid production. Complementation of ldhL1 in the above knockout strains restored fermentation profiles to those observed in the wild-type strain. This study demonstrates ldhL1 is crucial for L-lactic acid production and NADH balance in B. coagulans DSM1 and lays the fundamental for engineering the thermotolerant B. coagulans strain as a platform chemicals producer.
Collapse
|
11
|
Song W, Cheng J, Zhao J, Zhang C, Zhou J, Cen K. Enhancing hydrogen production of Enterobacter aerogenes by heterologous expression of hydrogenase genes originated from Synechocystis sp. BIORESOURCE TECHNOLOGY 2016; 216:976-980. [PMID: 27343449 DOI: 10.1016/j.biortech.2016.06.044] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/29/2016] [Revised: 06/10/2016] [Accepted: 06/12/2016] [Indexed: 06/06/2023]
Abstract
The hydrogenase genes (hoxEFUYH) of Synechocystis sp. PCC 6803 were cloned and heterologously expressed in Enterobacter aerogenes ATCC13408 for the first time in this study, and the hydrogen yield was significantly enhanced using the recombinant strain. A recombinant plasmid containing the gene in-frame with Glutathione-S-Transferase (GST) gene was transformed into E. aerogenes ATCC13408 to produce a GST-fusion protein. SDS-PAGE and western blot analysis confirm the successful expression of the hox genes. The hydrogenase activity of the recombinant strain is 237.6±9.3ml/(g-DW·h), which is 152% higher than the wild strain. The hydrogen yield of the recombinant strain is 298.3ml/g-glucose, which is 88% higher than the wild strain. During hydrogen fermentation, the recombinant strain produces more acetate and butyrate, but less ethanol. This is corresponding to the NADH metabolism in the cell due to the higher hydrogenase activity with the heterologous expression of hox genes.
Collapse
Affiliation(s)
- Wenlu Song
- State Key Laboratory of Clean Energy Utilization, Zhejiang University, Hangzhou 310027, China; Department of Life Science and Engineering, Jining University, Jining 273155, China
| | - Jun Cheng
- State Key Laboratory of Clean Energy Utilization, Zhejiang University, Hangzhou 310027, China.
| | - Jinfang Zhao
- College of Agriculture and Biotechnology, Zhejiang University, Hangzhou 310029, China; Key Laboratory of Fermentation Engineering (Ministry of Education), College of Bioengineering, Hubei University of Technology, Wuhan 430068, China
| | - Chuanxi Zhang
- College of Agriculture and Biotechnology, Zhejiang University, Hangzhou 310029, China
| | - Junhu Zhou
- State Key Laboratory of Clean Energy Utilization, Zhejiang University, Hangzhou 310027, China
| | - Kefa Cen
- State Key Laboratory of Clean Energy Utilization, Zhejiang University, Hangzhou 310027, China
| |
Collapse
|
12
|
Du GQ, Xue C, Zhao QQ, Xu J, Liu T, Chen LJ, Mu Y, Bai FW. Design of online off-gas analysis system for anaerobic ABE fermentation and the strategy for improving biobutanol production. Process Biochem 2016. [DOI: 10.1016/j.procbio.2016.02.010] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/13/2023]
|
13
|
Lu Y, Zhao H, Zhang C, Xing XH. Insights into the global regulation of anaerobic metabolism for improved biohydrogen production. BIORESOURCE TECHNOLOGY 2016; 200:35-41. [PMID: 26476162 DOI: 10.1016/j.biortech.2015.10.007] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/26/2015] [Revised: 10/02/2015] [Accepted: 10/06/2015] [Indexed: 06/05/2023]
Abstract
To improve the biohydrogen yield in bacterial dark fermentation, a new approach of global anaerobic regulation was introduced. Two cellular global regulators FNR and NarP were overexpressed in two model organisms: facultatively anaerobic Enterobacter aerogenes (Ea) and strictly anaerobic Clostridium paraputrificum (Cp). The overexpression of FNR and NarP greatly altered anaerobic metabolism and increased the hydrogen yield by 40%. Metabolic analysis showed that the global regulation caused more reducing environment inside the cell. To get a thorough understanding of the global metabolic regulation, more genes (fdhF, fhlA, ppk, Cb-fdh1, and Sc-fdh1) were overexpressed in different Ea and Cp mutants. For the first time, it demonstrated that there were approximately linear relationships between the relative change of hydrogen yield and the relative change of NADH yield or ATP yield. It implied that cellular reducing power and energy level played vital roles in the biohydrogen production.
Collapse
Affiliation(s)
- Yuan Lu
- Key Lab of Industrial Biocatalysis of Ministry of Education (Tsinghua University), China; Institute of Biochemical Engineering, Department of Chemical Engineering, Tsinghua University, Beijing 100084, China
| | - Hongxin Zhao
- Key Lab of Industrial Biocatalysis of Ministry of Education (Tsinghua University), China; Institute of Biochemical Engineering, Department of Chemical Engineering, Tsinghua University, Beijing 100084, China; Zhejiang Province Key Laboratory of Plant Secondary Metabolism and Regulation, College of Life Sciences, Zhejiang Sci-Tech University, Hangzhou 310018, China; College of Chemistry and Life Sciences, Shenyang Normal University, Shenyang 110034, China
| | - Chong Zhang
- Key Lab of Industrial Biocatalysis of Ministry of Education (Tsinghua University), China; Institute of Biochemical Engineering, Department of Chemical Engineering, Tsinghua University, Beijing 100084, China
| | - Xin-Hui Xing
- Key Lab of Industrial Biocatalysis of Ministry of Education (Tsinghua University), China; Institute of Biochemical Engineering, Department of Chemical Engineering, Tsinghua University, Beijing 100084, China.
| |
Collapse
|