Preparation of high molecular weight pH-responsive lignin-polyethylene glycol (L-PEG) and its application in enzymatic saccharification of lignocelluloses

摘要

Highly recyclable pH-responsive lignin-polyethylene glycol (L-PEG) was synthesized to achieve enhanced lignocellulosic hydrolysis and recycling cellulase. The performance of L-PEG could be easily regulated by adjusting the molecular weight and the amount of PEG. The large molecular weight facilitated L-PEG to reduce the invalid adsorption of cellulase on lignin during hydrolysis and enhance its flocculation effect at around pH 3.0. L-PEG(1000-40) obtained by adding 40 wt% (based on lignin) PEG1000 could effectively enhance the enzymatic hydrolysis of lignocelluloses and recover most of cellulase after hydrolysis through simply adjusting the pH of hydrolysate. During eucalyptus hydrolysis, using L-PEG(1000-40) to recycle cellulase could not only save 40% cellulase, but also increase the glucose yield by 121%. Due to the low synthesis cost of L-PEG and the simple and convenient recovery operation, this new method is beneficial to the improvement of lignocellulosic saccharification process and the high-value utilization of lignin. Graphic abstract