Bifidobacteria Xylan Degradation Enzymes And Their Use Efficiency Of Xos

Bifidobacteria are anaerobic bacteria in the human large intestine, which are capable of using oligosaccharides as carbon sources. Due to the health-promoting effects on humans, they are generally considered as probiotic and important components of the human intestinal microbiota.In this work, we examined the xylanolytic enzyme systems in B. adolescentis, B. bifidum and B. infantis, and their activities on the degradation of XOSs. All these species produced only xylosidase and arabinosidase, and no xylanase, α-glucuronidase and acetyl xylan esterase were found from them. When the bacteria were grown in the medium contained XOSs, xylosidase and arabinosidase activities (Umg^-1) determined at 45°C and 37°C were 0.993 and 0.084 in B. adolescentis, 0.787 and 0.025 in B. infantis, and 0.644 and 0.022 in B. bifidum, respectively.The xylosidase and arabinosidase activities in B. adolescentis differed when the organism grown in the media (0.1%, w/v soya peptone) with glucose, xylose or XOSs as main carbon sources. The organism produce more xylosidase when gown on xylose and XOSs than on glucose. The highest level of arabinosidase was produced when the organism was grown on XOSs.The optimal activity of P-D-xylosidase from B. adolescentis was at pH 5.6 and 45°C, and α-L-arabinoside was at pH 5.0 and 40°C. The degradation products of XOSs by cell-free extracts and the growth rate of B. adolescentis were tested over XOSs and XOSs de-branched by recombinant α-glucuronidase. The results showed that de-branching of a-glucuronidase increased the production of xylose and the total cell density by 10%, and accelerated the growth of B. adolescentis by 20%.