Assimilation of  N-acetylsucrosamine by  Bifidobacterium spp.

Abstract

 In an investigation of the assimilation of a newly synthesized non-natural N-acetylsucrosamine (SucNAc) by Bifidobacterium spp., we identified one species, Bif. catenulatum, that utilizes SucNAc in the presence of glucose, but not as a sole carbon source, and another species, Bif. pseudocatenulatum, that utilizes SucNAc as a sole carbon source. In culture, Bif. catenulatum growth occurred in two stages, with glucose being utilized in the first stage and SucNAc being used in the second stage (diauxie). Assessment of sugar degradation activity by bacterial extracts revealed that although Bif. catenulatum basically expresses sugar-degrading enzymes at low levels, new enzymatic activity is observed when SucNAc is utilized as a carbon source. In contrast, Bif. pseudocatenulatum basically expresses a variety of sugar-degrading enzymes. Elucidation of the mechanism that allows SucNAc, which is not utilized as a sole carbon source by Bif. catenulatum to be utilized in the presence of glucose will lead to a deeper understanding of sugar utilization by Bifidobacterium spp.