کد مقاله | کد نشریه | سال انتشار | مقاله انگلیسی | نسخه تمام متن |
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1282114 | 1497548 | 2012 | 11 صفحه PDF | دانلود رایگان |
An NADH dehydrogenase encoded by the nuo cluster was isolated and impaired by knocking out the nuoB gene in Enterobacter aerogenes to examine its effect on hydrogen production. Three nuoB-deleted mutant strains were constructed from the wild-type strain E. aerogenes IAM1183 and two recombinant strains, IAM1183-A (ΔhycA) and IAM1183-O (ΔhybO), from which the hycA and hybO genes had already been deleted previously, respectively. Compared with the performance of the wild-type strain, the overall hydrogen production of the mutants IAM1183-B (ΔnuoB), IAM1183-AB (ΔhycA/ΔnuoB) and IAM1183-BO (ΔhybO/ΔnuoB) was increased by 49.2%, 54.0%, and 52.4% in batch culture, respectively. The hydrogen yields from glucose by the three mutants IAM1183-B, IAM1183-AB, IAM1183-BO were 1.38, 1.49, and 1.39 mol H2/mol glucose, respectively, while it was 1.16 mol H2/mol glucose in the wild-type strain. Metabolic flux analysis indicated that all three mutants exhibited reduced fluxes to lactate production, and enhanced fluxes toward the generation of hydrogen, acetate, ethanol, succinate and 2,3-butanediol. Both the formate pathway and the NADH pathway contributed to increased hydrogen production in the mutant strains. The assay of 4 NADH-mediated enzyme activities (H2ase, LDH, ADH and BDDH) was in accordance with the redistributions of the metabolic fluxes in the mutant strains.
► An NADH dehydrogenase encoded by the nuo cluster was isolated in Enterobacter aerogenes.
► Deleting the nuoB gene resulted in a substantial increase in hydrogen production.
► Reduced fluxes to lactate were found in all three nuoB-deleted mutant strains.
► Changes in NADH-mediated enzyme activities agreed with metabolic redistributions.
Journal: International Journal of Hydrogen Energy - Volume 37, Issue 21, November 2012, Pages 15875–15885