Comparison of sulfomethylated lignin from poplar and masson pine on cellulase adsorption and the enzymatic hydrolysis of wheat straw.

In this work, effects of sulfomethylated lignins (SLs) prepared from masson pine (SL) and poplar (SL) on enzymatic hydrolysis and cellulase-lignin interaction were comparatively investigated. The results showed that both SL and SL significantly promoted the substrate enzymatic digestibility. The total sugar yield increased from 38.6% to 74.4% and ∼ 100%, respectively at 10 FPU/g-cellulose of cellulase dosage. The protein content in hydrolysate linearly increased with the addition of SL (0 - 1.6 g/g-substrate lignin), which suggested the competitive adsorption of cellulase may occur to substrate lignin and SLs. Further structural analysis of lignin revealed the high S/(V + H) ratio was directly related to the high enzymatic saccharification efficiency. The strong interaction between SL and cellulase decreased the nonproductive adsorption of cellulase onto substrate lignin and increased the accessibility of cellulase to carbohydrate, which was considered to be the key factor for the improvement of substrate enzymatic digestibility.