Efficient production of xylobiose and xylotriose from xylan in moso bamboo by the combination of pH-controlled lactic acid and xylanase hydrolysis

Short-chain xylo-oligosaccharides (XOS) such as xylobiose (X2) and xylotriose (X3) have higher biological activities. Therefore, it is interesting to produce highly active XOS enriched with X2 and X3. In this work, pHcontrolled lactic acid (LA) hydrolysis was used to produce XOS from xylan in moso bamboo and xylanase was used to convert high DP XOS into low DP XOS to increase the percentage of X2 + X3 in XOS. A 33.1 % XOS yield was obtained from 2 % LA hydrolysis (pH = 3.2). After xylanase hydrolysis of the LA hydrolysate, the total XOS yield reached 64.1 %, with X2 + X3 yield reaching 58.4 %. The percentage of X2 + X3 increased from 52.3 % to a high level of 91.0 %. The deep eutectic solvent pretreatment removed 87.2 % lignin from the residue and the glucose yield of the delignified residue hydrolyzed by cellulase was 96.9 %. The results suggested that the integrated process of LA and xylanase hydrolysis could effectively produce X2 + X3 from xylan in moso bamboo.