Enzymatic production of xylooligosaccharides from alkali solubilized xylan of natural grass (Sehima nervosum)

Abstract

In this study, a process for producing XOS from Sehima nervosum grass was developed. The grass contains 28.1% hemicellulose. NaOH and steam application yielded 98% of original xylan in contrast to 85% by KOH application. Hydrolysis of xylan with commercial xylanase caused breakdown into XOS comprising of xylobiose, xylotriose along with xylose. Response surface model (RSM) revealed highest xylobiose yield (11 g/100g xylan) at pH 5.03, temperature 45.19°C, reaction time 10.11h with enzyme dose 17.41 U. Similarly for maximizing xylotriose yield, ideal hydrolysis conditions were pH 5.11, temperature 40.33°C, reaction time 16.55 h with enzyme dose 13.20 U. A two step process encompassing xylan fractionation and enzymatic hydrolysis enabled XOS production from the S. nervosum grass.