Novel redox potential-based screening strategy for rapid isolation of Klebsiella pneumoniae mutants with enhanced 1,3-propanediol-producing capability

Chenyu Du, Yanping Zhang, Yin Li, Zhu'an Cao

Research output: Contribution to journalArticle

43 Citations (Scopus)

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.

Original languageEnglish
Pages (from-to)4515-4521
Number of pages7
JournalApplied and Environmental Microbiology
Volume73
Issue number14
DOIs
Publication statusPublished - 1 Jul 2007
Externally publishedYes

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