title: Effects of over-expression of glycerol dehydrogenase and 1,3-propanediol oxidoreductase on bioconversion of glycerol into 1,3-propandediol by Klebsiella pneumoniae under micro-aerobic conditions.
abstract: Glycerol dehydrogenase (GDH) and 1,3-propanediol (1,3-PD) oxidoreductase had been proved two key enzymes for 1,3-PD production by Klebsiella pneumoniae. Fed-batch fermentations of the recombinant K. pneumoniae strains, over-expressing the two enzymes individually, were carried out under micro-aerobic conditions, and the behaviors of the recombinants were investigated. Results showed that over-expression of 1,3-PD oxidoreductase did not affect the concentration of 1,3-PD. However, it enhanced the molar yield from 50.6 to 64.0% and reduced the concentration of by-products. Among them, the concentrations of lactic acid, ethanol and succinic acid were decreased by 51.8, 50.6 and 47.4%, respectively. Moreover, in the recombinant the maximal concentration of 3-hydroxypropionaldehyde decreased by 73.6%. Over-expression of GDH decreased the yield of ethanol and 2,3-butanediol, meanwhile it increased the concentration of acetic acid. No significant changes were observed both in 1,3-PD yield and glycerol flux distributed to oxidative branch.
authors.affiliation: State Key Laboratory of Bioreactor Engineering, New World Institute of Biotechnology, East China University of Science and Technology, 200237, Shanghai, People's Republic of China.
authors.forename: Li
authors.initials: L
authors.lastname: Zhao
authors.forename: Yu
authors.initials: Y
authors.lastname: Zheng
authors.forename: Xingyuan
authors.initials: X
authors.lastname: Ma
authors.forename: Dongzhi
authors.initials: D
authors.lastname: Wei
mesh_terms: D000426:Alcohol Dehydrogenase; D000429:Alcohol Oxidoreductases / Q000235:genetics / Q000378:metabolism*; D015964:Gene Expression Regulation, Bacterial / Q000502:physiology*; D024861:Genetic Enhancement / Q000379:methods; D005990:Glycerol / Q000378:metabolism*; D007711:Klebsiella pneumoniae / Q000502:physiology*; D010100:Oxygen / Q000378:metabolism*; D011409:Propylene Glycols / Q000378:metabolism*; D015202:Protein Engineering / Q000379:methods*; D011994:Recombinant Proteins / Q000378:metabolism; D013401:Sugar Alcohol Dehydrogenases / Q000235:genetics / Q000378:metabolism*; D015854:Up-Regulation / Q000502:physiology
chemical_list: D011409:Propylene Glycols; D011994:Recombinant Proteins; C041787:1,3-propanediol; D000429:Alcohol Oxidoreductases; D013401:Sugar Alcohol Dehydrogenases; D000426:Alcohol Dehydrogenase; C052370:1,3-propanediol dehydrogenase; C020672:glycerol dehydrogenase; D005990:Glycerol; D010100:Oxygen