The influence of thermal drying pretreatment on enzymatic hydrolysis of cellulose and xylan in poplar fibers with high lignin content

Thermal drying for lignocellulosic fibers is a common procedure in laboratories and factories, which isn't a pretreatment traditionally used to enhance cellulose conversion but inevitably occurs. This study investigated the effects of thermal drying conditions on the characteristics and enzymatic hydrolysis of lignocellulosic fiber granules with high lignin content. The results showed that fiber characteristics decreased linearly with the increase of temperature, which caused the linear reduction of enzymatic digestibility. Then, the increase of time caused the exponential decrease of fiber characteristics and enzymatic digestibility. Moreover, the reduction of initial water content obtained by centrifugation resulted in almost the same porosity and slightly increased water retention value (WRV) of fibers, which caused slight changes of lignocellulose digestibility. Finally, repeated drying and swelling led to complex changes in fiber characteristics, which caused fluctuations in enzymatic hydrolysis with a downward trend. This article will provide a reference for lignocellulose enzymatic hydrolysis.