Physiologic mechanisms of sequential products synthesis in 1,3-propanediol fed-batch fermentation by Klebsiella pneumoniae.
The glycerol fed-batch fermentation by Klebsiella pneumoniae CGMCC 1.6366 exhibited the sequential synthesis of products, including acetate, 1,3-propanediol (1,3-PD), 2,3-butanediol, ethanol, succinate, and lactate. The dominant flux distribution was shifted from acetate formation to 1,3-PD formation in early- exponential growth phase and then to lactate synthesis in late-exponential growth phase. The underlying physiological mechanism of the above observations has been investigated via the related enzymes, nucleotide, and intermediary metabolites analysis. The carbon flow shift is dictated by the intrinsic physiological state and enzymatic activity regulation. Especially, the internal redox state could serve as a rate-controlling factor for 1,3-PD production. The q(1,3-PD) formation was the combined outcomes of regulations of glycerol dehydratase activity and internal redox balancing. The q(ethanol)/q(acetate) ratios demonstrated the flexible adaptation mechanism of K. pneumoniae preferring ATP generation in early-exponential growth phase. A low PEP to pyruvate ratio corresponded LDH activity increase, leading to lactate accumulation in stationary phase.
Zheng
Zong-Ming
ZM
Department of Chemical Engineering, Tsinghua University, Beijing 100084, China.
Xu
Yun-Zhen
YZ
Liu
Hong-Juan
HJ
Guo
Ni-Ni
NN
Cai
Zhong-Zhen
ZZ
Liu
De-Hua
DH
D019149:Bioreactors / Q000382:microbiology*; D018929:Cell Culture Techniques / Q000379:methods*; D003198:Computer Simulation; D007711:Klebsiella pneumoniae / Q000378:metabolism*; D008954:Models, Biological; D011409:Propylene Glycols / Q000378:metabolism*
D011409:Propylene Glycols; C041787:1,3-propanediol