Production of xylooligosaccharides from corncob xylan by fungal xylanase and their utilization by probiotics.

The selective production of xylooligosaccharides (XOS) was carried out using partially purified xylanase from Aspergillus foetidus MTCC 4898. Corncob xylan was extracted using a mild alkali treatment which yielded 178.73±5.8 g of xylan/kg of corncobs. Partially purified β-xylosidase free xylanase was found efficient in releasing xylooligosaccharides from corncob xylan. Maximum yield of xylooligosaccharides was 6.73±0.23 mg/ml after 8 h of reaction time using 20 U of xylanase at 45°C. Purification of XOS was done using activated charcoal column chromatography. The purified XOS preparation contained mainly xylobiose and xylotriose. XOS mixture was found suitable for food industry looking at its high thermal stability at low pH. Prebiotic effect of XOS was evaluated by in vitro fermentation of XOS using known probiotic strains viz. Bifidobacterium adolescentis, Bifidobacterium bifidum, Lactobacillus fermentum, Lactobacillus acidophilus. The results of this study revealed better growth of Bifidobacterium spp. on XOS than Lactobacillus spp.