Effect of overexpression of malate dehydrogenase on succinic acid production in Escherichia coli NZN111.
- Author:
Liya LIANG
1
;
Jiangfeng MA
;
Rongming LIU
;
Guangming WANG
;
Bing XU
;
Min ZHANG
;
Min JIANG
Author Information
1. State Key Laboratory of Materials-Oriented Chemical Engineering, College of Biotechnology and Pharmaceutical Engineering, Nanjing University of Technology, Nanjing 210009, China.
- Publication Type:Journal Article
- MeSH:
Acetyltransferases;
genetics;
Anaerobiosis;
Escherichia coli;
genetics;
metabolism;
Fermentation;
Gene Knockout Techniques;
Glucose;
metabolism;
L-Lactate Dehydrogenase;
genetics;
Malate Dehydrogenase;
genetics;
metabolism;
Mutation;
Recombinant Proteins;
biosynthesis;
genetics;
Recombination, Genetic;
Succinic Acid;
metabolism
- From:
Chinese Journal of Biotechnology
2011;27(7):1005-1012
- CountryChina
- Language:Chinese
-
Abstract:
Escherichia coli NZN111 is a double mutant with lactate dehydrogenase (ldhA) and pyruvate formate-lyase (pflB) inactivated. Under anaerobic conditions, disequilibrium of coenzyme NADH and NAD+ causes Escherichia coli NZN111 losing the glucose utilizing capability. In this study, we constructed a recombinant strain E. coli NZN111/pTrc99a-mdh and overexpressed the mdh gene with 0.3 mmol/L of IPTG under anaerobic fermentation condition in sealed bottles. The specific malate dehydrogenase (MDH) activity in the recombinant strain was 14.8-fold higher than that in E. coli NZN111. The NADH/ NAD+ ratio decreased from 0.64 to 0.26 and the concentration of NAD+ and NADH increased 1.5-fold and 0.2-fold respectively. Under anaerobic conditions, the recombinant strain possessed the capability of growth and glucose absorption. We took dual-phase fermentation for succinate production. After the dry cell weight (DCW) reached 6.4 g/L under aerobic conditions, the cell culture was changed to anaerobic conditions. After 15 h, 14.75 g/L glucose was consumed and succinic acid reached 15.18 g/L. The yield of succinic acid was 1.03 g/g Glu and the productivity of succinic acid was 1.012 g/(L x h).
