Combining autohydrolysis with xylanase hydrolysis for producing xylooligosaccharides from Jiuzao

Abstract

In this report, a versatile process for producing xylooligosaccharides (XOS) with great prebiotic potential from Jiuzao, a residue from Baijiu distillation, was designed. This two-stage process integrated autohydrolysis with subsequent enzymatic hydrolysis by the recombinant thermostable xylanase, XynAS, produced by Escherichia coli. The effect of several autohydrolysis parameters (i.e., temperature, time, particle size and solid-liquid ratio) on XOS yield were examined by single factor and response surface methods. The maximum XOS yield was 30.4%, which was obtained at 181.2 °C for 20 min with a 1:13.4 solid-liquid ratio for the autohydrolysis step, and pH 6, 60 °C, 5 U/mL XynAS loading and an incubation period of 2 h for the enzymatic hydrolysis step. Using these reaction conditions, xylobiose and xylotriose were the major XOS products, constituting 86.6% of the total XOS yield. The results demonstrated that autohydrolysis combined with xylanase hydrolysis is an effective and eco-friendly approach for XOS production using Jiuzao as the substrate.