Complete breakdown the cellulose-saccharification barrier of inert masson pine by gluconic acid-peroxide pretreatment under moderate temperature

A two-step process combining solvent extraction and hydrogen peroxide-gluconic acid (HP-GA) pretreatment was employed to effectively remove the barriers affecting the enzymatic saccharification of masson pine cellulose. Ethanol extraction removes bioactive phenolics and eliminates the negative effect of the following pretreatment and cellulose saccharification. The gluconic acid (GA)-based peroxide was formed by mixing hydrogen peroxide (HP) with GA, which effectively pretreated inert masson pine with the synergistic oxidative degradation and dissolution of lignin and hemicellulose. During the pretreatment, various organic peracid catalysts were detected such as peroxy-GA, peroxy-acetic acid, and peroxy-formic acid. After ethanol extraction at 80 °C and HP-GA pretreatment at 90 °C, 95.4 % of lignin and 69.2 % of hemicellulose could be removed from masson pine, and the enzymatic hydrolysis of cellulose resulted in 99.2 % glucose yield. Based on GA and the green-electric derived H 2 O 2 , this work provides an ecological and efficient pretreatment method to completely break down the critical biorefinery barriers on enzymatic saccharification of cellulose, especially concerning inert softwood-type lignocellulosic biomass.