In vitro fermentation of xylo-oligosaccharides from corn cobs autohydrolysis by Bifidobacterium and Lactobacillus strains

The selective release of soluble oligomeric structures from corn cobs (CC) by autohydrolysis was optimized using the severity factor (log R0), and a maximum xylo-oligosaccharides (XOS) production was obtained at log R0=3.75. Gel filtration chromatography was employed to separate oligosaccharides (OS) from the crude hydrolysate and two fractions with average degrees of polymerization (DP) of 3–4 and 5–6 were compared with commercial XOS in their ability to promote the growth of Bifidobacterium adolescentis, B. longum, Lactobacillus brevis and L. fermentum as carbon and energy sources. Among the tested strains, B. adolescentis and L. brevis displayed the highest growth and XOS consumption, in contrast to B. longum and L. fermentum whose overall growth on XOS was low. XOS mixtures from CC autohydrolysis, mainly constituted by xylotriose and xylotetraose, were fermented by B. adolescentis as well as commercial XOS containing essentially xylobiose, whereas L. brevis preferred XOS with an average DP of 2. However, an increase in XOS chain length to DP 5–6 clearly reduced the extension to which B. adolescentis utilized these OS. This study showed that XOS of low molecular weight from CC autohydrolysis exhibit a potential bifidogenic capability similar to commercial XOS.