Uncommon pathways of metabolism among lactic acid bacteria.

A small number of lactic acid bacteria possess the ability to derive energy from organic molecules not utilized by the vast majority of representatives of this large group of microorganisms. Thus, strains of Lactobacillus casei and enterococci readily grow at the expense of substrates such as gluconate, malate and pentitols. Transport of gluconate and pentitols is catalysed by phosphotransferase systems unique to these bacteria. Similarly, the initial steps in pentitol dissimilation are mediated by enzymes found only in Lb. casei and Streptococcus avium.