Human gut Bacteroides uniformis utilizes mixed linked β- glucans via an alternative strategy

Abstract

Human gut microbial communities have a tremendous impact on well-being of the human health by producing myriad of metabolites. Polysaccharide utilizing capability of these microbial communities is a key driving force in shaping the composition of gut microbiota. Previous studies suggest that genes responsible for β- glucans utilizing in Bacteroides are present in a polysaccharide utilization locus (PUL). However, recent observations show that Bacteroides uniformis lacks such PUL archetypal organisation for efficient utilization of pustulan (β1-6) and mixed linkage (β1-4/ β1-3) glucans, and its mechanism is yet to be studied. Here, we first used BuGH16 for production of important two mixed linked β- glucan-oligosaccharides, and then demonstrate kinetics of the BuGH3MLG. The B. uniformis JCM13288T coordinates between PUL associated glycoside hydrolase (GH)-16 and distantly localised bespoke GH 3 (BuGH3MLG) for efficient utilization of mixed linkage (β1-4/ β1-3) glucans. BuGH3MLG found to be cleaved β1-4, β1-3 and β1-6 glucan-oligosaccharides. Such understanding of glycan utilization mechanism of human gut bacterial communities is crucial for development of nutraceutical therapy and improving health of human being.