Open AccessImpact of acetolactate synthase inactivation on 1,3-propanediol fermentation by Klebsiella pneumoniae
Author(s) -
Sheng Zhou,
Youhua Huang,
Xinliang Mao,
Lili Li,
Chuanyu Guo,
Yongli Gao,
Qiwei Qin
Publication year - 2019
Publication title -
plos one
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.99
H-Index - 332
ISSN - 1932-6203
DOI - 10.1371/journal.pone.0200978
Subject(s) - klebsiella pneumoniae , fermentation , acetolactate synthase , 1,3 propanediol , glycerol , chemistry , biochemistry , cofactor , mutant , enzyme , microbiology and biotechnology , biology , escherichia coli , gene
1,3-Propanediol (1,3-PDO) is an important compound that is mainly used in industry for polymer production. Fermentation of 1,3-PDO from glycerol by Klebsiella pneumoniae is accompanied by formation of 2,3-butanediol (2,3-BDO) as one of the main byproduct. The first step in the formation of 2,3-BDO from pyruvate is catalyzed by acetolactate synthase (ALS), an enzyme that competes with 1,3-PDO oxidoreductase for the cofactor NADH. This study aimed to analyze the impact of engineering the 2,3-BDO formation pathway via inactivation of ALS on 1,3-PDO fermentation by K . pneumoniae HSL4. An ALS mutant was generated using Red recombinase assisted gene replacement. The ALS specific activities of K . pneumoniae ΔALS were notably lower than that of the wild-type strain. Fed-batch fermentation of the mutant strain resulted in a 1,3-PDO concentration, productivity and conversion of 72.04 g L –1 , 2.25 g L –1 h –1 , and 0.41 g g –1 , increase by 4.71%, 4.65% and 1.99% compared with the parent strain. Moreover, inactivation of ALS decreased meso -2,3-BDO formation to trace amounts, significantly increased 2S,3S-BDO and lactate production, and a pronounced redistribution of intracellular metabolic flux was apparent.