Variations in the energy metabolism of biotechnologically relevant heterofermentative lactic acid bacteria during growth on sugars and organic acids

Appl Microbiol Biotechnol. 2006 Sep;72(3):421-9. doi: 10.1007/s00253-006-0514-3. Epub 2006 Jul 7.

Abstract

Heterofermentative lactic acid bacteria (LAB) such as Leuconostoc, Oenococcus, and Lactobacillus strains ferment pentoses by the phosphoketolase pathway. The extra NAD(P)H, which is produced during growth on hexoses, is transferred to acetyl-CoA, yielding ethanol. Ethanol fermentation represents the limiting step in hexose fermentation, therefore, part of the extra NAD(P)H is used to produce erythritol and glycerol. Fructose, pyruvate, citrate, and O2 can be used in addition as external electron acceptors for NAD(P)H reoxidation. Use of the external acceptors increases the growth rate of the bacteria. The bacteria are also able to ferment organic acids like malate, pyruvate, and citrate. Malolactic fermentation generates a proton potential by substrate transport. Pyruvate fermentation sustains growth by pyruvate disproportionation involving pyruvate dehydrogenase. Citrate is fermented in the presence of an additional electron donor to acetate and lactate. Thus, heterofermentative LAB are able to use a variety of unusual fermentation reactions in addition to classical heterofermentation. Most of the reactions are significant for food biotechnology/microbiology.

Publication types

  • Research Support, Non-U.S. Gov't
  • Review

MeSH terms

  • Aldehyde-Lyases / metabolism
  • Arginine / metabolism
  • Biotechnology / methods
  • Citric Acid / metabolism
  • Energy Metabolism*
  • Fermentation*
  • Gram-Positive Bacteria / growth & development*
  • Gram-Positive Bacteria / metabolism*
  • Hexoses / metabolism*
  • Lactic Acid / metabolism*
  • Malates / metabolism
  • Pyruvic Acid / metabolism

Substances

  • Hexoses
  • Malates
  • Citric Acid
  • Lactic Acid
  • malic acid
  • Pyruvic Acid
  • Arginine
  • Aldehyde-Lyases
  • phosphoketolase