title: High efficiency hydrogen production from glucose/xylose by the ldh-deleted Thermoanaerobacterium strain.
abstract: A strictly anaerobic, thermoacidophilic, H(2)-producing bacterium was isolated and designated as Thermoanaerobacterium aotearoense. The optimized cultivation conditions for H(2) production are 55 degrees C, pH 6.5 and 10gl(-1) of glucose or xylose. A metabolic pathway analysis showed that lactate occupied most of the liquid metabolites and consumed a large amount of NADH. To increase the efficiency of hydrogen production, the gene encoding the l-lactate dehydrogenase was knocked out to redirect the NADH flow. Genetic manipulation resulted in the 2 and 2.5 folds increase of the H(2) yield and production rate, respectively. The maximum H(2) yields using the Deltaldh mutant were 2.71, 1.45 and 2.28molH(2)mol(-1) sugar under glucose, xylose and glucose/xylose mixture tests, respectively. The recombinant Deltaldh strain could ferment the mixture of glucose and xylose to produce H(2) effectively, indicating that the performance of Thermoanaerobacterium in H(2) production can be significantly improved by metabolic engineering technique.
authors.affiliation: School of Bioscience and Bioengineering, South China University of Technology, Guangzhou, China.
authors.forename: Shuang
authors.initials: S
authors.lastname: Li
authors.forename: Chaofeng
authors.initials: C
authors.lastname: Lai
authors.forename: Youhua
authors.initials: Y
authors.lastname: Cai
authors.forename: Xiaofeng
authors.initials: X
authors.lastname: Yang
authors.forename: Shuai
authors.initials: S
authors.lastname: Yang
authors.forename: Mingjun
authors.initials: M
authors.lastname: Zhu
authors.forename: Jufang
authors.initials: J
authors.lastname: Wang
authors.forename: Xiaoning
authors.initials: X
authors.lastname: Wang
mesh_terms: D056804:Biofuels / Q000382:microbiology*; D017353:Gene Deletion; D020868:Gene Silencing; D024861:Genetic Enhancement / Q000379:methods*; D005947:Glucose / Q000378:metabolism*; D006859:Hydrogen / Q000302:isolation & purification / Q000378:metabolism*; D007770:L-Lactate Dehydrogenase / Q000235:genetics*; D046950:Thermoanaerobacterium / Q000502:physiology*; D014994:Xylose / Q000378:metabolism*
chemical_list: D056804:Biofuels; D006859:Hydrogen; D014994:Xylose; D007770:L-Lactate Dehydrogenase; D005947:Glucose