Improving xylo-oligosaccharides yield from corn stalk with stepwise enzymolysis

Valorization of renewable carbon sources such as lignocellulosic biomass (LCB) or agricultural residues to produce value-added bioproducts has attracted increasing attention. In this way, a sustainable and abundantly present biopolymer xylan can be utilized to produce xylo-oligosaccharide (XOS) which has potential benefits for individuals and the environment as well. Xylan can be enzymatically degraded into XOS via enzymatic hydrolysis (EH), but the inherently recalcitrant xylan limiting the yield of XOS by incomplete hydrolysis. The aim of this study is to identify the factors hindering the efficient EH of extracted xylan from corn stalk (CS). For this purpose, xylan extracted from CS sequentially fractionated into three different fractions followed by primary enzymolysis, acetic acid treatment, and secondary enzymolysis. The results showed that the structural complexity, degree of branching, and/or substituents of the substrate also played a vital role during enzymolysis and therefore the solubility was not the only factor to determine the hydrolysis ratio. Compared with the primary enzymolysis, the yield of XOS from CS extracted xylan increased from 48 to 67% with an additional 10% of xylose obtained in the dual enzymolysis and acid treatment. The total enzymolysis ratio reached up to 77% with only 0.15 xylose to XOS yield.