Combined liquid hot water with sodium carbonate-oxygen pretreatment to improve enzymatic saccharification of reed

Abstract

In this work, two-stage combination of liquid hot water (LHW) and Na2CO3-O2 pretreatment was performed efficiently on reed to obtain fermentable sugar. Reed was first treated with LHW at 170 °C for 60 min and then with Na2CO3-O2. The optimal conditions for Na2CO3-O2 pretreatment were as follow: reaction temperature of 150 °C, residence time of 40 min, Na2CO3 concentration of 33.3 g/L and oxygen pressure of 0.6 MPa. The total sugar yield of 79.1% was achieved with a cellulase of 20 FPU/g-pretreated solid for 48 h. The total sugar yield improved 36.0% compared with single Na2CO3-O2 pretreatment. The combined pretreatment could avoid the loss of carbohydrate degradation. The total sugar yield was increased by 48.6% compared to only LHW pretreatment. Owing to advantages of the combined pretreatment breaking the restraint of lignin and cellulose, LHW combined with Na2CO3-O2 pretreatment was a promising method for the production of fermentable sugar.