Co-production of xylooligosaccharides and glucose from birch sawdust by hot water pretreatment and enzymatic hydrolysis

A green method for co-production of value-added xylooligosaccharides (XOS) and glucose from birch was demonstrated using hot water pretreatment. Effects of pretreatment severity factor (Log R-0) on XOS production and enzymatic hydrolysis were investigated. At Log R-0 of 4.05 (180 ?C, 50 min), the maximum hydrolysis yield (80.8%) was obtained. At Log R0 of 3.91 (170 ?C, 70 min), the maximum XOS yield (46.1%) was obtained, however the hydrolysis yield decreased to 70.3%. To achieve both the high XOS yield and high glucose output, Tween 80 addition (0.075 g/g cellulose) was employed, leading to an improvement in hydrolysis yield from 70.3% to 89.4%. From a mass balance perspective, 104.6 g of XOS and 372.9 g of glucose could be produced from 1000 g birch. These results demonstrated that birch sawdust is a promising lignocellulosic material for coproduction of XOS and glucose.