Physiological characterization of three lactic acid bacteria and their isogenic ldh deletion mutants shows that these organisms are optimized for Yatp and not ATP formation rates at their physiological pH


Several lactic acid bacteria use homolactic fermentation for generation of ATP. Here we studied the role of the lactate dehydrogenase enzyme on the general physiology of the three homolactic acid bacteria Lactococcus lactis, Enterococcus faecalis and Streptococcus pyogenes. Of note, deletion of the ldh genes hardly affected the growth rate in chemically defined medium in microaerophilic conditions. 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 the growth rate for S. pyogenes and dependent on the pH for E. faecalis. In S. pyogenes and L. lactis a change in pH resulted in a clear change in Yatp. The pH that showed the highest Yatp corresponded to the pH of the natural habitat of the organisms.


PubMed ID: 21097579

Projects: SysMO-LAB

Publication type: Not specified


Date Published: 25th Nov 2010

Registered Mode: Not specified

Authors: , , , , Anja Pritzschke, Nikolai Siemens, , ,

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Views: 4436

Created: 30th Nov 2010 at 14:40

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