Due to the intact structure of lignocellulosic biomass, pretreatment was a prerequisite to improve the enzymatic hydrolysis by disrupting the recalcitrant lignocellulose and increasing the accessibility of cellulose to enzyme. In this study, an alkaline hydrogen peroxide (AHP) pretreatment of sugarcane bagasse with various loadings of H2O2 (1.25–6.25 wt%) at temperatures of 60–160 °C was proposed to degrade hemicellulose/lignin and improve the enzymatic digestibility. It was found that increasing H2O2 loadings during pretreatment lead to the enhancement of substrate digestibility, whereas the alkali (only NaOH)-pretreated solid generated higher glucose yield than that pretreated under AHP pretreatment with lower loading of H2O2. This enhancement of enzymatic digestibility was due to the degradation of hemicellulose and lignin. Furthermore, Tween 80 was added to promote enzymatic digestibility, however, the increased yields were different with various substrates and hydrolysis time. The highest glucose yield of 77.6% was obtained after pretreatment at 160 °C for 60 min with 6.25% H2O2 and the addition of Tween 80, representing 89.1% of glucose in pretreated substrate. This study demonstrated that the AHP pretreatment could greatly enhance the enzymatic saccharification. The addition of Tween 80 played remarkable performances in promoting the glucose yield during enzymatic hydrolysis by stabilizing and protecting the enzyme activity. This study provided an economical feasible and gradual process for the generation of glucose, which will be subsequently converted to bioethanol and bio-chemicals.

The recalcitrant structure of lignocellulosic biomass made it challenging for their bioconversion into biofuels and biochemicals. Pretreatment was required to deconstruct the intact structure by the removal of hemicellulose/lignin, improving the cellulose accessibility of enzyme. Combinatorial pretreatments with liquid hot water/H2SO4 and ethanol/NaOH of sugarcane bagasse were developed to improve enzymatic hydrolysis under mild conditions. After one-step 60% ethanol containing 0.5% NaOH pretreatment with solid to liquid ratio of 1/10, the glucose yield after hydrolysis for 72 h with enzyme dosage of 20 FPU/g substrate was enhanced by 41% and 205% compared to that of NaOH or 60% ethanol pretreated solids, respectively. This improvement was correlated with the removal of hemicellulose and lignin. However, using combinatorial pretreatments with 1% H2SO4 followed by 60% ethanol containing 0.5% NaOH, the highest glucose yield with Tween 80 reached 76%, representing 84.5% of theoretical glucose in pretreated substrate. While retaining similar glucose yield, the addition of Tween 80 capacitated either a reduction of enzyme loading by 50% or shortening hydrolysis time to 24 h. However, the enhancement with the addition of Tween 80 decreased as hydrolysis time was extended. This study demonstrated that a combinatorial pretreatment with 1% H2SO4 followed by 60% ethanol containing 0.5% NaOH had significant effects on improving the enzymatic hydrolysis of sugarcane bagasse. The addition of Tween 80 enabled reducing the enzyme loading or shortening the hydrolysis time. This study provided an economically feasible and mild process for the generation of glucose, which will be subsequently converted to bioethanol and biochemicals.