AUTHOR=Sanchez-Gallardo Rocio , Bottacini Francesca , Friess Lisa , Esteban-Torres Maria , Somers Clarissa , Moore Rebecca L. , McAuliffe Fionnuala M. , Cotter Paul D. , van Sinderen Douwe 

TITLE=Unveiling metabolic pathways of selected plant-derived glycans by Bifidobacterium pseudocatenulatum

JOURNAL=Frontiers in Microbiology

VOLUME=15

YEAR=2024

URL=https://www.frontiersin.org/journals/microbiology/articles/10.3389/fmicb.2024.1414471

DOI=10.3389/fmicb.2024.1414471

ISSN=1664-302X

ABSTRACT=<p>Bifidobacteria are commonly encountered members of the human gut microbiota that possess the enzymatic machinery necessary for the metabolism of certain plant-derived, complex carbohydrates. In the current study we describe differential growth profiles elicited by a panel of 21 newly isolated <italic>Bifidobacterium pseudocatenulatum</italic> strains on various plant-derived glycans. Using a combination of gene-trait matching and comparative genome analysis, we identified two distinct xylanases responsible for the degradation of xylan. Furthermore, three distinct extracellular α-amylases were shown to be involved in starch degradation by certain strains of <italic>B. pseudocatenulatum</italic>. Biochemical characterization showed that all three α-amylases can cleave the related substrates amylose, amylopectin, maltodextrin, glycogen and starch. The genes encoding these enzymes are variably found in the species <italic>B. pseudocatenulatum</italic>, therefore constituting a strain-specific adaptation to the gut environment as these glycans constitute common plant-derived carbohydrates present in the human diet. Overall, our study provides insights into the metabolism of these common dietary carbohydrates by a human-derived bifidobacterial species.</p>