Application of a recombinant GH10 endoxylanase from Thermoascus aurantiacus for xylooligosaccharide production from sugarcane bagasse and probiotic bacterial growth

Xylooligosaccharides (XOs) are a promising class of prebiotics capable of selectively stimulating the growth of the beneficial intestinal microbiota against intestinal pathogens. They can be obtained from xylan present in residual lignocellulosic material from agriculture. Thus, in this study we produced XOs by extracting xylan from sugarcane bagasse and hydrolyzing it using the GH10 xylanase from Thermoascus aurantiacus expressed by Pichia pastoris. An alkaline method to extract xylan is described, which resulted in 83.40% of xylan recovery and low amounts of cellulose and lignin. The enzymatic hydrolysate exhibited a mixture of XOs containing mainly xylobiose, xylotriose and xylotetraose. These oligosaccharides stimulated the growth of Lactobacillus casei, L. rhamnosus, L. fermentum and L. bulgaricus strains, which were able to produce organic acids, especially acetic acid. These findings demonstrate the possibility to redirect crop by-products to produce XOs and their use as a supplement to stimulate the growth of probiotic strains.