Metabolism of the predominant human milk oligosaccharide fucosyllactose by an infant gut commensal

International audienceA number of bifidobacterial species are found at a particularly highprevalence and abundance in faecal samples of healthy breastfed infants,a phenomenon that is believed to be, at least partially, due to theability of bifidobacteria to metabolize Human Milk Oligosaccharides(HMOs). In the current study, we isolated a novel strain ofBifidobacterium kashiwanohense, named APCKJ1, from the faeces of a four-week old breastfed infant, based on the ability of the strain to utilisethe HMO component fucosyllactose. We then determined the full genomesequence of this strain, and employed the generated data to analyzefucosyllactose metabolism in B. kashiwanohense APCKJ1. Transcriptomicand growth analyses, combined with metabolite analysis, in vitrohydrolysis assays and heterologous expression, allowed us to elucidatethe pathway for fucosyllactose metabolism in B. kashiwanohense APCKJ1.Homologs of the key genes for this metabolic pathway were identified inparticular in infant-derived members of the Bifdobacterium genus,revealing the apparent niche-specific nature of this pathway, andallowing a broad perspective on bifidobacterial fucosyllactose andL-fucose metabolism