Alteration of hydrogen metabolism of ldh-deleted Enterobacter aerogenes by overexpression of NAD(+)-dependent formate dehydrogenase

Institute of Biochemical Engineering, Department of Chemical Engineering, Tsinghua University, Beijing 100084, China.
Applied Microbiology and Biotechnology (Impact Factor: 3.34). 10/2009; 86(1):255-62. DOI: 10.1007/s00253-009-2274-3
Source: PubMed


The NAD+-dependent formate dehydrogenase FDH1 gene (fdh1), cloned from Candida boidinii, was expressed in the ldh-deleted mutant of Enterobacter aerogenes IAM1183 strain. The plasmid of pCom10 driven by the PalkB promoter was used to construct the fdh1 expression system and thus introduce a new dihydronicotinamide adenine dinucleotide (NADH) regeneration pathway from formate in the ldh-deleted mutant. The knockout of NADH-consuming lactate pathway affected the whole cellular metabolism, and the hydrogen yield increased by 11.4% compared with the wild strain. Expression of fdh1 in the ldh-deleted mutant caused lower final cell concentration and final pH after 16 h cultivation, and finally resulted in 86.8% of increase in hydrogen yield per mole consumed glucose. The analysis of cellular metabolites and estimated redox state balance in the fdhl-expressed strain showed that more excess of reducing power was formed by the rewired NADH regeneration pathway, changing the metabolic distribution and promoting the hydrogen production.

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    • "Metabolic engineering has recently been recognized as one of the most important potential technologies to improve fermentative hydrogen yield. Some researches have aimed at improving the yield of originally good hydrogen producers (wild-type Clostridium sp., Enterobacter sp.), but the genetic manipulation is relatively hard [4] [5] [6] [7] [8]. Escherichia coli, the best-characterized bacterium, was chosen as the starting model strain to study ways of improving the hydrogen yield by the manipulation of its metabolism [9]. "
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    Biochemical Engineering Journal 01/2012; 60:81-86. DOI:10.1016/j.bej.2011.10.006 · 2.47 Impact Factor
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    • "Zhang et al. (2009) suggested that the exogenous addition of NADH or NAD + could change the intracellular redox state of E. aerogenes and, subsequently, the H 2 production through formate and NADH pathways. In a consecutive study, Lu et al. (2010) improved the H 2 yield in E. aerogenes IAM 1183 to 1.70 from 0.91 mol H 2 /mol glucose by inactivating NADH-consuming lactate dehydrogenase and overexpressing NAD + -dependent formate dehydrogenase. However, detailed genetic and biochemical characterizations for NADH-dependent H 2 production machineries in E. aerogenes sp. "
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    1974 Ultrasonics Symposium; 02/1974
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