title: Improvement of 1,3-propanediol production in Klebsiella pneumoniae by moderate expression of puuC (encoding an aldehyde dehydrogenase).
abstract: OBJECTIVE
  To improve 1,3-propanediol production in Klebsiella pneumoniae, the effects of puuC expression in lactate- and lactate/2,3-butanediol-deficient strains were assessed.
  
  
  RESULTS
  Overexpression of puuC (encoding an aldehyde dehydrogenase) inhibited 1,3-propanediol production and increased 3-hydroxypropionic acid formation in both lactate- and lactate/2,3-butanediol-deficient strains. An improvement in 1,3-propanediol production was only achieved in a lactate-deficient strain via moderate expression of puuC; at the end of the fermentation, 1,3-propanediol productivity increased by 14% compared with the control. Further comparative analysis of the metabolic flux distributions in different strains indicated that 3-hydroxypropionic acid formation could play a considerable role in cell metabolism in K. pneumoniae.
  
  
  CONCLUSIONS
  An improvement in 3-hydroxypropionic acid formation would be beneficial for cell metabolism, which can be accomplished by enhancing 1,3-propanediol productivity in a lactate-deficient strain via moderate expression of puuC.
authors.affiliation: State Key Laboratory of Bioreactor Engineering, East China University of Science and Technology, 130 Meilong Road, Shanghai, 200237, People's Republic of China.
authors.forename: Chengqian
authors.initials: C
authors.lastname: Zhu
authors.forename: Xiao
authors.initials: X
authors.lastname: Jiang
authors.forename: Yongqiang
authors.initials: Y
authors.lastname: Zhang
authors.forename: Jie
authors.initials: J
authors.lastname: Lin
authors.forename: Shuilin
authors.initials: S
authors.lastname: Fu
authors.forename: Heng
authors.initials: H
authors.lastname: Gong
mesh_terms: D000444:Aldehyde Dehydrogenase / Q000235:genetics / Q000378:metabolism*; D001426:Bacterial Proteins / Q000235:genetics / Q000378:metabolism; D005285:Fermentation; D007711:Klebsiella pneumoniae / Q000201:enzymology* / Q000235:genetics; D019344:Lactic Acid / Q000031:analogs & derivatives / Q000378:metabolism; D011409:Propylene Glycols / Q000378:metabolism*
chemical_list: D001426:Bacterial Proteins; D011409:Propylene Glycols; D019344:Lactic Acid; C041787:1,3-propanediol; C031601:hydracrylic acid; D000444:Aldehyde Dehydrogenase