Effects of cellulose and lignin on xylooligosaccharides production from xylan: The superiority of acetic acid/sodium acetate hydrolysis

Xylooligosaccharides (XOS) are high-value products derived from xylan in lignocellulose and have a variety of prebiotic applications. The intertwining of xylan, cellulose, and lignin in lignocelluloses may affect XOS production. In order to investigate those impacts, the comparative analysis of XOS production was conducted using corncob, poplar and xylan as substrates through the hydrolysis using acetic acid/sodium acetate (AC/SA), acetic acid (AC), and pure water. The results revealed that the hydrolysis of different feedstocks using AC/SA generated the highest XOS yield and the least by-products compared to AC hydrolysis and hydrothermal (HT) treatment. The presence of cellulose led to the reductions of XOS production from xylan by AC/SA hydrolysis, AC hydrolysis, and HT treatment by 6.6%, 6.3%, and 4.3%, respectively. The presence of cellulose and lignin largely decreased XOS yields by 22.2%, 22.0%, and 88.5%, respectively. Obviously, the cellulose slightly inhibited xylan hydrolysis, while lignin had a strong negative effect on xylan hydrolysis. Besides, the adverse effect of lignin on xylan hydrolysis was the greatest in HT treatment. Despite the presence of cellulose and lignin, AC/SA hydrolysis exhibited the superior ability in XOS production and reduced the formation of by-products compared to AC hydrolysis and HT treatment.