Elevating enzymatic hydrolysis efficiency and ethanol yield of poplar by hydrogen peroxide assisted p-toluenesulfonic acid pretreatment

Utilizing hydrogen peroxide (H2O2) and acid medium for oxidation-reduction reaction to facilitate the efficient biorefining of lignocellulose is the ultimate goal of oxidative pretreatment. Here, the p-toluenesulfonic acid (TsOH) was employed in the H2O2 pretreatment of poplar, which has achieved excellent depolymerizing effect of lignin and xylan. The results displayed that 99.9% xylan and 68.4% lignin were dramatically removed when 2% H2O2 and 40 g/L TsOH were introduced to the pretreatment (HTP) at 160 °C. After enzymatic hydrolysis and simultaneous saccharification and fermentation, the enzymatic hydrolysis efficiency and ethanol yield of poplar were advanced by 59.0% and 59.4%, respectively. The structural characterization indicated that the incremental efficiency was attributed to the advantageous accessibility, surface area, crystallinity, and crystal size of poplar by HTP's augmentative removal of non-cellulosic components. This work expanded the application of acidic H2O2 pretreatment and suggested that HTP was a synergistic and feasible way in biorefinery.