Effects of characteristics of poplar substrate obtained by combining dilute acid with mechanical pretreatment on the enzymatic hydrolysis

It is believed that the substrate characteristics of lignocellulosic biomass are important factors influencing their conversion into fermentable sugars. In this study, the poplar chips were subjected to dilute acid pretreatment under different intensities combining with mechanical refining. After that the characteristics of substrate were analyzed, and the effects of substrate characteristics on the enzymatic hydrolysis efficiency were evaluated. The results showed that the enzymatic hydrolysis efficiency was enhanced obviously after the pretreatment mainly due to the changes of substrate characteristics. It was also found that 1) the chemical compositions were alternated obviously, i.e., the xylan content of substrate was reduced, and the glucan and lignin had a relative increase, the surface lignin of poplar substrate were increased firstly and then decreased with increasing the pretreatment intensity; 2) the specific surface area and fines content of poplar substrate were increased firstly and then decreased; 3)the crystallinity and kink index of the substrates had a downward trend while the mean length of fiber was decreased with increasing the pretreatment intensity. It was found that the specific surface, fines content and surface lignin had a significant influence on the enzymatic hydrolysis efficiency. The aim of this study was to investigate the effects of different dilute acid pre-treatment intensities combining with mechanical refining on the enzymatic hydrolysis of poplar chips, which will help and enable the development of a cost-efficient pre-treatment strategy for the biomass processing.