title: Deletion of poxB, pta, and ackA improves 1,3-propanediol production by Klebsiella pneumoniae.
abstract: To date, few studies have focused on reducing the toxic by-product acetate during 1,3-propanediol production by Klebsiella pneumoniae. In this study, the effects of deleting the poxB, pta, and ackA genes, which are involved in the two main acetate synthesis pathways, on cell growth and 1,3-propanediol production were investigated. Although acetate synthesis via pyruvate oxidase (PoxB, encoded by poxB) generally seems unnecessary and wasteful, PoxB was shown to play an important role in K. pneumoniae. Deletion of poxB severely inhibited cell growth, and the poxB mutant exhibited an anomalously high accumulation of acetate in aerobic cultures and failed to produce an endogenous supply of carbon dioxide (CO2) in anaerobic cultures. It is interesting that both the aerobic and anaerobic growth defects of the poxB mutant were corrected by further deleting pta and ackA, which blocked the other main acetate synthesis pathway. The poxB-pta-ackA mutant excreted less acetate and showed an excellent ability to produce 1,3-propandiol. The final 1,3-propanediol yield and concentration in a 2-L fed-batch fermentation reached 0.66 (mol/mol) and 76.8 g/L, respectively, which were 16 and 15 % greater, respectively, than those of the parent strain.
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: Jie
authors.initials: J
authors.lastname: Lin
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: Yongqiang
authors.initials: Y
authors.lastname: Zhang
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: Danfeng
authors.initials: D
authors.lastname: Xu
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: Gang
authors.initials: G
authors.lastname: Xiang
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: Zongxiao
authors.initials: Z
authors.lastname: Jia
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: Shuilin
authors.initials: S
authors.lastname: Fu
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. gongheng@ecust.edu.cn.
authors.forename: Heng
authors.initials: H
authors.lastname: Gong
mesh_terms: D000085:Acetates / Q000378:metabolism / Q000633:toxicity; D000332:Aerobiosis; D000693:Anaerobiosis; D001426:Bacterial Proteins / Q000235:genetics*; D005285:Fermentation; D017353:Gene Deletion; D007711:Klebsiella pneumoniae / Q000235:genetics* / Q000254:growth & development / Q000378:metabolism*; D060847:Metabolic Engineering / Q000379:methods*; D053858:Metabolic Networks and Pathways / Q000235:genetics*; D011409:Propylene Glycols / Q000378:metabolism*
chemical_list: D000085:Acetates; D001426:Bacterial Proteins; D011409:Propylene Glycols; C041787:1,3-propanediol
keywords: 1,3-Propanediol; Acetate; Klebsiella pneumonia; ackA; poxB; pta