Delignification of poplar for xylo-oligosaccharides production using lactic acid catalysis

Recently, xylo-oligosaccharides (XOS) production from lignocelluloses by organic acid catalysis has been widely reported. However, the effect of delignification of lignocelluloses on XOS production by organic acid catalysis was unclear, and lactic acid (LA) catalysis in XOS production from lignocelluloses has not been reported. In this work, the effect of delignification on XOS production from poplar by LA catalysis was investigated. Results demonstrated that hydrogen peroxide-acetic acid (HPAA) pretreatment removed 83.2% of lignin and retained 95.4% of xylan. After 2% LA catalysis (170 °C, 30 min), a high XOS yield of 42.7% was obtained from HPAA₁-LA-pretreated poplar. Lignin removal from poplar was positively correlated with XOS yield. Glucose yield of HPAA₁-LA-pretreated poplar by cellulase was 88.9%. Compared with LA-catalyzed poplar, the XOS and glucose production from HPAA₁-LA-pretreated poplar by cellulase increased by 1.4-fold and 6.8-fold, respectively. This work presents a novel strategy for efficient producing XOS and monosaccharides from poplar.