Affiliation:
1. Institute of Biochemical Engineering, Department of Chemical Engineering, Tsinghua University, Beijing 100084, People's Republic of China
2. Institute of Microbiology, Chinese Academy of Sciences, Beijing 100101, People's Republic of China
Abstract
ABSTRACT
This report describes a novel redox potential (oxidoreduction potential [ORP])-based screening strategy for the isolation of mutants of
Klebsiella pneumoniae
which have an increased ability to produce 1,3-propanediol (1,3-PD). This method can be described as follows: first, to determine an ORP range which is preferred for the wild-type strain to grow and to produce 1,3-PD; second, to subject a chemically mutagenized culture to a reduced ORP level which is deleterious for the wild-type strain. Colonies that showed high specific growth rates at deleterious ORP levels were selected, and their abilities to produce 1,3-PD were investigated. In an ORP-based screening experiment where the ORP was controlled at −280 mV, 4 out of 11 isolated strains were recognized as positive mutant strains. A mutant which is capable of producing higher concentrations of 1,3-PD was subjected to fed-batch fermentations for further characterization. Its preferred ORP level (−280 mV) was significantly lower than that of its parent (−190 mV). The highest 1,3-PD concentration of the mutant was 915 mmol liter
−1
, which was 63.1% higher than that of the parent. Metabolic-flux analysis suggested that the intracellular reductive branch of the mutant was strengthened, which improved 1,3-PD biosynthesis. The procedure and results presented here provide a novel method of screening for strains with improved product formation.
Publisher
American Society for Microbiology
Subject
Ecology,Applied Microbiology and Biotechnology,Food Science,Biotechnology
Cited by
44 articles.
订阅此论文施引文献
订阅此论文施引文献,注册后可以免费订阅5篇论文的施引文献,订阅后可以查看论文全部施引文献