Enhanced H2 Production and Redirected Metabolic Flux via Overexpression of fhlA and pncB in Klebsiella HQ-3 Strain

Jawed, Muhammad; Pi, Jian; Xu, Li; Zhang, Houjin; Yan, Yunjun

doi:10.1007/s12010-015-1932-4

Cited by 17 publications

(11 citation statements)

References 34 publications

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“…aerogenes [24,25], Enterobacter sp. CN1 [26], and Klebsiella HQ-3 [27], which has increased hydrogen production to some extent. However, these bacteria only utilized the synthetic medium for hydrogen production, or adding formic acid to promote hydrogen evolution.…”

Section: Discussionmentioning

confidence: 99%

Enhanced biohydrogen production from cotton stalk hydrolysate of Enterobacter cloacae WL1318 by overexpression of the formate hydrogen lyase activator gene

Zhang

You

et al. 2020

Preprint

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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 high 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 (Rm), 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’s 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.

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Section: Discussionmentioning

confidence: 99%

Enhanced biohydrogen production from cotton stalk hydrolysate of Enterobacter cloacae WL1318 by overexpression of the formate hydrogen lyase activator gene

Zhang

You

et al. 2020

Preprint

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“…Photo-autotrophic microorganisms like cyanobacteria or green microalgae used the method of bio-photolysis that possess chlorophyll A and other pigments and has a capacity to capture sunlight and split water to make H 2 . Even though, there are some barriers in this method such as: the O 2 evolved during this method suppresses the activation of hydrogenase subunits, gas mixture formed during the process is combustible, low photosynthetic conversion efficiencies and large surface area requirement engineering of biological systems for improvement in BHP [3], [4]. A precise genome-scale model of an organism helps us in studying the effect of environmental and genetic limitations on it, and hence these facts motivate experiments in the area of metabolic engineering.…”

Section: Methods For Biohydrogen Productionmentioning

confidence: 99%

Bioinformatics Approaches for Improvement of Biohydrogen Production: A Review

Jawed¹,

Wang²,

Pi³

et al. 2017

IJESD

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Abstract-Hydrogen (H 2 ) production from biomass is considered as the main source of renewable energy, is a characteristic feature of prokaryotes. H 2 is believed as the cleanest fuel without evolution of greenhouse gases on combustion. The main biological processes for H 2 production are: biophotolysis of water by algae and cyanobacteria, dark fermentation and photo-fermentation. Since last decades, a lot of work has been carried out for understanding and refining bio-hydrogen production and still it has to overcome some of the serious limitations so that it becomes a viable proposal. The bottlenecks include thermodynamic inefficiency, trouble in using lignocellulosics as feedstock, cost of raw material and low H 2 molar yields (HMY). To get rid of these major problems, the conventional approach is inadequate and people has to dynamically think modern bioinformatics approaches to overcome these factors. The accessibility of enormous sequenced genomes, functional genomic studies, and the progress of in-silico models at the genome level, metabolic pathway reconstruction, and synthetic biology tactics predict engineering strategies to enhance H 2 production in an organism. This review examines the current status and progressions that have been made in the area of biotechnology and bioinformatics, to understand and enhance H 2 evolution to overcome current limitations and make H 2 production from biological means, a reality in the coming future.Index Terms-Biohydrogen, in-silico metabolic engineering, functional genomics, synthetic biology.

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“…Nevertheless, research on the FHL complex in other species of the Enterobacter genus is still limited; only a few studies have reported fhlA gene expression in Enterobacter aerogenes [22], Enterobacter sp. CN1 [23] and Klebsiella HQ-3 [24], whereas the fhlA gene of Enterobacter cloacae and its expression have not yet been reported.…”

Section: Introductionmentioning

confidence: 99%

Enhanced biohydrogen production from cotton stalk hydrolysate of Enterobacter cloacae WL1318 by overexpression of the formate hydrogen lyase activator gene

Zhang

You

et al. 2020

Preprint

View full text Add to dashboard Cite

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 . However, little work has been reported in terms of the fhlA gene cloning and expression in Enterobacter cloacae as well as the engineered strain for lignocellulose-based hydrogen production.Results The formate hydrogen lyase activator ( fhlA ) gene was cloned and overexpressed in Enterobacter cloacae WL1318, and the cumulative hydrogen production and dynamics, glucose and xylose consumption, cell growth, and soluble metabolites were analyzed in the wild and recombinant strains. The results showed 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(H 2 /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’s 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.

show abstract

Enhanced H2 Production and Redirected Metabolic Flux via Overexpression of fhlA and pncB in Klebsiella HQ-3 Strain

Cited by 17 publications

References 34 publications

Enhanced biohydrogen production from cotton stalk hydrolysate of Enterobacter cloacae WL1318 by overexpression of the formate hydrogen lyase activator gene

Enhanced biohydrogen production from cotton stalk hydrolysate of Enterobacter cloacae WL1318 by overexpression of the formate hydrogen lyase activator gene

Bioinformatics Approaches for Improvement of Biohydrogen Production: A Review

Enhanced biohydrogen production from cotton stalk hydrolysate of Enterobacter cloacae WL1318 by overexpression of the formate hydrogen lyase activator gene

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