A cyclic process for enzymatic hydrolysis and fermentation of lactic acid pretreated reed

This research aims to explore a green, economical and recyclable pretreatment method to enhance the enzymatic digestibility of reed. In this study, lactic acid (LA) as a kind of weak organic acid was used to pretreat reed. The results of orthogonal experiments showed that temperature was the most dominant influencing factor for the pretreatment process. Linear experiments conducted the optimum temperature for LA pretreatment of reed was 150 °C. Under this condition, the lignin removal reached 90.46%, glucan recovery was 89.80%, glucan digestibility was 66.43%, and the final sugar yields reached 60.70%. LA fermentation using the liquid obtained from enzymatic hydrolysis . The sugar acids conversion rate was 37.89%, which was 17.05% higher than that obtained by fermentation of pure glucose. Moreover, the product lactic acid can be widely used either as feed or to prepare polylactic acid and it also can continue to be used in the pretreatment of reed. • A high lignin removal rate of 90.46% was achieved after lactic acid (LA) pretreatment. • The glucan yield of 60.70% was achieved after enzymatic hydrolysis of LA pretreated reed. • The yield of LA from the fermentation of hydrolyzed sugars was similar to that of the pure sugars. • LA pretreatment is a green and recyclable biomass pretreatment method.