Study of the physiological characterization of three lactic acid bacteria and their isogenic ldh deletion mutants

Lactic acid bacteria generally use homolactic fermentation for generation of ATP. Here we studied the role of the lactate dehydrogenase enzyme on the general physiology of the three lactic acid bacteria Lactococcus lactis, Enterococcus faecalis and Streptococcus pyogenes. Surprisingly deletion of the ldh genes hardly affected the growth rate in chemically defined medium, however growth rate was affected in rich medium. Furthermore, deletion of ldh affected the ability for utilization of various substrates as a carbon source. A switch to mixed acid fermentation was observed in glucose-limited continuous growth and was dependent on growth rate for S. pyogenes and pH dependeny in E. faecalis. In S. pyogenes and L. lactis a change in pH resulted in a clear change in Yatp demand. The pH that showed the highest Yatp corresponded to the pH of the natural habitat of the organisms.


Investigation of glycolysis and pyruvate branching of three lactic acid bacteria

Projects: SysMO-LAB

Martijn Bekker

Experimentalists: Martijn Bekker

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Created: 11th Jun 2010 at 10:56

Last updated: 11th May 2016 at 17:19

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