[Effect of overexpression of malate dehydrogenase on succinic acid production in Escherichia coli NZN111]

Sheng Wu Gong Cheng Xue Bao. 2011 Jul;27(7):1005-12.
[Article in 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).

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Acetyltransferases / genetics
  • Anaerobiosis
  • Escherichia coli / genetics
  • Escherichia coli / metabolism*
  • Fermentation
  • Gene Knockout Techniques
  • Glucose / metabolism
  • L-Lactate Dehydrogenase / genetics
  • Malate Dehydrogenase / genetics
  • Malate Dehydrogenase / metabolism*
  • Mutation*
  • Recombinant Proteins / biosynthesis
  • Recombinant Proteins / genetics
  • Recombination, Genetic
  • Succinic Acid / metabolism*

Substances

  • Recombinant Proteins
  • Succinic Acid
  • L-Lactate Dehydrogenase
  • Malate Dehydrogenase
  • Acetyltransferases
  • formate C-acetyltransferase
  • Glucose