Enzymatic Production of Prebiotic Xylooligosaccharides Using a <i>Bacillus pumilus</i> GH30_8 Glucuronoxylanase: Structural Basis of Glucuronoxylan Recognition and Hydrolysis

Transformation of agro-industrial products into value-added products, such as prebiotic oligosaccharides, is a key element of the emerging bioeconomy. Here, we characterized a new GH30_8 glucuronoxylanase from <i>Bacillus pumilus</i> (<i>Bp</i>Xyn30_8A) for its potential in producing xylooligosaccharides (XOS). <i>Bp</i>Xyn30_8A showed tolerance to ethanol and NaCl and released both linear and branched XOS containing MeGlcA at the penultimate nonreducing end residue. Its X-ray structure, determined at 2.16 Å resolution, revealed high similarity to other glucuronoxylanases. Furthermore, <i>Bp</i>Xyn30_8A achieved higher xylan conversion yields from corn cob and <i>Eucalyptus</i> sawdust than <i>Ruminococcus champanellensis</i><i>Rc</i>Xyn30A. Finally, fermentation assays showed that <i>Bifidobacterium adolescentis</i> metabolized neutral XOS to acetate and lactate, whereas acidic XOS were poorly utilized. These results highlight the potential of <i>Bp</i>Xyn30_8A as a valuable enzyme for the green transformation of plant biomass into prebiotic oligosaccharides with promising applications in human and animal nutrition, health, and biotechnology.