Open AccessTranscriptional and functional characterization of genetic elements involved in galacto‐oligosaccharide utilization by B ifidobacterium breve UCC 2003
Author(s) -
O'Connell Motherway Mary,
Kinsella Michael,
Fitzgerald Gerald F.,
Sinderen Douwe
Publication year - 2013
Publication title -
microbial biotechnology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.287
H-Index - 74
ISSN - 1751-7915
DOI - 10.1111/1751-7915.12011
Subject(s) - bifidobacterium breve , prebiotic , inulin , oligosaccharide , biology , biochemistry , chemistry , bifidobacterium , fermentation , lactobacillus
Summary Several prebiotics, such as inulin, fructo‐oligosaccharides and galacto‐oligosaccharides, are widely used commercially in foods and there is convincing evidence, in particular for galacto‐oligosaccharides, that prebiotics can modulate the microbiota and promote bifidobacterial growth in the intestinal tract of infants and adults. In this study we describe the identification and functional characterization of the genetic loci responsible for the transport and metabolism of purified galacto‐oligosaccharides ( PGOS ) by B ifidobacterium breve UCC 2003. We further demonstrate that an extracellular endogalactanase specified by several B . breve strains, including B . breve UCC 2003, is essential for partial degradation of PGOS components with a high degree of polymerization. These partially hydrolysed PGOS components are presumed to be transported into the bifidobacterial cell via various ABC transport systems and sugar permeases where they are further degraded to galactose and glucose monomers that feed into the bifid shunt. This work significantly advances our molecular understanding of bifidobacterial PGOS metabolism and its associated genetic machinery to utilize this prebiotic.