Xylanase-mediated control of xylooligosaccharide polymerization degree following acetic acid buffer hydrolysis of bamboo

Organic acid hydrolysis from lignocelluloses to produce xylooligosaccharides (XOS) is efficient, but the uncertainty of the distribution of the XOS lead to low bioactivity of XOS. In the present work, XOS was produced from moso bamboo by acetic acid/sodium acetate (AC/SA) system, and the XOS composition and distribution was adjusted by xylanase (XYL). The maximum XOS yield was 42.1 % under the optimal conditions of 2.0 M AC/SA, pH 4.0, 180 °C, 40 min. The subsequent XYL hydrolysis successfully transformed XOS with a degree of polymerization (DP) higher than 6 to low-DP XOS and the final XOS yield reached 65.7 %. The total yield of xylobiose and xylotriose reached a high level of 40.9 %, accounting for 62.2 % of the total XOS. After removing most of lignin from the solid residue with sodium hydroxide, glucose was produced by cellulolytic hydrolysis. When the cellulase load was 15 FPU/g dry matter, the yield of glucose was 93.4 %. This work suggested that XYL hydrolysis after AC/SA hydrolysis of bamboo could achieve a high XOS yield with high bioactivity components from moso bamboo. • High XOS yield of 65.7 % was achieved from bamboo after AC/SA and xylanase hydrolysis. • NaOH pretreatment resulted in highly selective removal of lignin. • High glucose yield of 93.4 % was produced from bamboo residue after cellulase hydrolysis. • High-DP XOS from bamboo was converted to low DP-XOS by xylanase.