title: A genetic and metabolic approach to redirection of biochemical pathways of Clostridium butyricum for enhancing hydrogen production.
abstract: Clostridium butyricum, a well known H(2) producing bacterium, produces lactate, butyrate, acetate, ethanol, and CO(2) as its main by-products from glucose. The conversion of pyruvate to lactate, butyrate and ethanol involves oxidation of NADH. It was hypothesized that the NADH could be increased if the formation of these by-products could be eliminated, resulting in enhancing H(2) yield. Herein, this study aimed to establish a genetic and metabolic approach for enhancing H(2) yield via redirection of metabolic pathways of a C. butyricum strain. The ethanol formation pathway was blocked by disruption of aad (encoding aldehyde-alcohol dehydrogenase) using a ClosTron plasmid. Although elimination of ethanol formation alone did not increase hydrogen production, the resulting aad-deficient mutant showed approximately 20% enhanced performance in hydrogen production with the addition of sodium acetate. This work demonstrated the possibility of improving hydrogen yield by eliminating the unfavorable by-products ethanol and lactate.
authors: School of Earth and Environmental Sciences, University of Adelaide, Adelaide, South Australia 5005, Australia.
authors: Guiqin
authors: G
authors: Cai
authors: Bo
authors: B
authors: Jin
authors: Paul
authors: P
authors: Monis
authors: Christopher
authors: C
authors: Saint
mesh_terms: D000426:Alcohol Dehydrogenase / Q000235:genetics / Q000378:metabolism; D046972:Clostridium butyricum / Q000201:enzymology / Q000235:genetics* / Q000378:metabolism*; D000431:Ethanol / Q000378:metabolism; D005285:Fermentation / Q000235:genetics; D005656:Fungal Proteins / Q000235:genetics / Q000378:metabolism; D005818:Genetic Engineering; D005947:Glucose / Q000378:metabolism; D006859:Hydrogen / Q000378:metabolism*; D053858:Metabolic Networks and Pathways / Q000235:genetics; D009243:NAD / Q000378:metabolism
chemical_list: D005656:Fungal Proteins; D009243:NAD; D000431:Ethanol; D006859:Hydrogen; D000426:Alcohol Dehydrogenase; D005947:Glucose