Effect of peracetic acid generation in hydrogen peroxide-acetic acid pretreatment on production of xylooligosaccharides from poplar by organic acid hydrolysis

•Peracetic acid generation occur mainly in the first 1 h.•Peracetic acid concentration and reaction time affected poplar lignin removal.•Delignification of poplar improved xylooligosaccharides yield using acetic acid.•Alkaline incubation made the glucose yield of final solid residue reached 97.1%. Hydrogen peroxide-acetic acid (HPAA) compositions affect the peracetic acid generation and subsequent delignification of lignocellulosic materials. However, the effects of HPAA compositions on lignin removal and poplar hydrolyzability after HPAA pretreatment are not fully elucidated yet. In this work, different volume ratios of HP to AA were used to pretreat poplar, AA and lactic acid (LA) hydrolysis of delignified poplar to produce XOS was compared. Peracetic acid was mainly produced in 1 h of HPAA pretreatment. HPAA with HP to AA ratio of 8:2 (HP8AA2) generated 4.4% peracetic acid and removed 57.7% of lignin at 2 h. Furthermore, XOS production from HP8AA2-pretreated poplar by AA and LA hydrolysis was increased by 97.1% and 14.9% compared to those from raw poplar, respectively. After alkaline incubation, the glucose yield of HP8AA2-AA-pretreated poplar increased from 40.1% to 97.1%. The study results indicated that HP8AA2 was conducive to XOS and monosaccharides production from poplar..