title: A novel whole-cell biocatalyst with NAD+ regeneration for production of chiral chemicals.
abstract: BACKGROUND
  The high costs of pyridine nucleotide cofactors have limited the applications of NAD(P)-dependent oxidoreductases on an industrial scale. Although NAD(P)H regeneration systems have been widely studied, NAD(P)(+) regeneration, which is required in reactions where the oxidized form of the cofactor is used, has been less well explored, particularly in whole-cell biocatalytic processes.
  
  
  RESULTS
  Simultaneous overexpression of an NAD(+) dependent enzyme and an NAD(+) regenerating enzyme (H(2)O producing NADH oxidase from Lactobacillus brevis) in a whole-cell biocatalyst was studied for application in the NAD(+)-dependent oxidation system. The whole-cell biocatalyst with (2R,3R)-2,3-butanediol dehydrogenase as the catalyzing enzyme was used to produce (3R)-acetoin, (3S)-acetoin and (2S,3S)-2,3-butanediol.
  
  
  CONCLUSIONS
  A recombinant strain, in which an NAD(+) regeneration enzyme was coexpressed, displayed significantly higher biocatalytic efficiency in terms of the production of chiral acetoin and (2S,3S)-2,3-butanediol. The application of this coexpression system to the production of other chiral chemicals could be extended by using different NAD(P)-dependent dehydrogenases that require NAD(P)(+) for catalysis.
authors.affiliation: State Key Laboratory of Microbial Technology, Shandong University, Jinan, People's Republic of China.
authors.forename: Zijun
authors.initials: Z
authors.lastname: Xiao
authors.forename: Chuanjuan
authors.initials: C
authors.lastname: Lv
authors.forename: Chao
authors.initials: C
authors.lastname: Gao
authors.forename: Jiayang
authors.initials: J
authors.lastname: Qin
authors.forename: Cuiqing
authors.initials: C
authors.lastname: Ma
authors.forename: Zhen
authors.initials: Z
authors.lastname: Liu
authors.forename: Peihai
authors.initials: P
authors.lastname: Liu
authors.forename: Lixiang
authors.initials: L
authors.lastname: Li
authors.forename: Ping
authors.initials: P
authors.lastname: Xu
mesh_terms: D055162:Biocatalysis; D004591:Electrophoresis, Polyacrylamide Gel; D004926:Escherichia coli / Q000378:metabolism; D006863:Hydrogen-Ion Concentration; D007700:Kinetics; D009097:Multienzyme Complexes / Q000378:metabolism; D009243:NAD / Q000378:metabolism*; D009247:NADH, NADPH Oxidoreductases / Q000378:metabolism; D011995:Recombination, Genetic; D013237:Stereoisomerism; D013379:Substrate Specificity
chemical_list: D009097:Multienzyme Complexes; D009243:NAD; C023107:NADH oxidase; D009247:NADH, NADPH Oxidoreductases