ABSTRACTDue to their potential prebiotic properties, arabinoxylan-derived oligosaccharides [(A)XOS] are of great interest as functional food and feed ingredients. While the (A)XOS metabolism ofBifidobacteriaceaehas been extensively studied, information regarding lactic acid bacteria (LAB) is still limited in this context. The aim of the present study was to fill this important gap by characterizing candidate (A)XOS hydrolyzing glycoside hydrolases (GHs) identified in the genome ofLactobacillus brevisDSM 20054. Two putative GH family 43 xylosidases (XynB1 and XynB2) and a GH family 43 arabinofuranosidase (Abf3) were heterologously expressed and characterized. While the function of XynB1 remains unclear, XynB2 could efficiently hydrolyze xylooligosaccharides. Abf3 displayed high specific activity for arabinobiose but could not release arabinose from an (A)XOS preparation. However, two previously reported GH 51 arabinofuranosidases fromLb. breviswere able to specifically remove α-1,3-linked arabinofuranosyl residues from arabino-xylooligosaccharides (AXHm3 specificity). These results imply thatLb. brevisis at least genetically equipped with functional enzymes in order to hydrolyze the depolymerization products of (arabino)xylans and arabinans. The distribution of related genes inLactobacillalesgenomes indicates that GH 43 and, especially, GH 51 glycosidase genes are rare among LAB and mainly occur in obligately heterofermentativeLactobacillusspp.,Pediococcusspp., members of theLeuconostoc/Weissellabranch, andEnterococcusspp. Apart from the prebiotic viewpoint, this information also adds new perspectives on the carbohydrate (i.e., pentose-oligomer) metabolism of LAB species involved in the fermentation of hemicellulose-containing substrates.
Bacteria Species Associated with Ugba (Pentaclethra macrophylla) Produced Traditionally and in the Laboratory and the Effect of Fermentation on Product of Oligosaccharide Hydrolysis
