Strategies for efficient repetitive production of succinate using metabolically engineered Escherichia coli

Bioprocess Biosyst Eng. 2011 May;34(4):411-8. doi: 10.1007/s00449-010-0484-9. Epub 2010 Nov 20.

Abstract

Escherichia coli AFP111, a pflB, ldhA, ptsG triple mutant of E. coli W1485, can be recovered for additional succinate production in fresh medium after two-stage fermentation (an aerobic growth stage followed by an anaerobic production stage). However, the specific productivity is lower than that of two-stage fermentation. In this study, three strategies were compared for reusing the cells. It was found when cells were aerobically cultivated at the end of two-stage fermentation without supplementing any carbon source, metabolites (mainly succinate and acetate) could be consumed. As a result, enzyme activities involved in the reductive arm of tricarboxylic acid cycle and the glyoxylate shunt were enhanced, yielding a succinate specific productivity above g⁻¹(DCW)h⁻¹ and a mass yield above 0.90 g g⁻¹ in the subsequent anaerobic fermentation. In addition, the intracellular NADH of cells subjected to aerobic cultivation with metabolites increased by more than 3.6 times and the ratio of NADH to NAD+ increased from 0.4 to 1.3, which were both favorable for driving the TCA branch to succinate.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Aerobiosis
  • Anaerobiosis
  • Biotechnology / methods*
  • Chemistry Techniques, Analytical / methods
  • Citric Acid Cycle
  • Culture Media
  • Escherichia coli / metabolism*
  • Fermentation
  • Models, Chemical
  • NAD / chemistry
  • Succinic Acid / chemistry*
  • Time Factors

Substances

  • Culture Media
  • NAD
  • Succinic Acid