Optimized phosphotungstic acid pretreatment for enhancing cellulase adsorption and biomass saccharification in corn stover

Corn stover is the abundant biowaste that can be utilized to produce biofuels and high value-added biological products. However, the complex structures of lignocellulose, on the other hand, are highly resistant to subsequent transformations. To promote enzymatic saccharification of corn stover, green and safe phosphotungstic acid was used to pretreat corn stover. Using a single-factor experiment and response surface approach, the influence of different pretreatment variables such as temperature, phosphotungstic acid concentration, pretreatment time, and solid-to-liquid ratio on the pretreatment effect was investigated. The best conditions were 126 ℃, 1.33%, 45 min, and 1:14, respectively, and the cellulose conversion rate was the greatest at 70.61% combined phosphotungstic acid and cellulase, raised by 171.99% when compared to the raw corn stover. Phosphotungstic acid was demonstrated to degrade both hemicellulose and lignin, yielding 25.89 mmol/L xylose. Phosphotungstic acid pretreatment samples were found to be more porous, with cellulase adsorption capacity increased from 161.56 to 245.70 mg/g biomass. CrI/cellulose was found to decrease from 1.09 to 0.77, indicating significant chemical alterations in corn stover functional linkages. These findings suggest that phosphotungstic acid enhances saccharification by altering the structure and chemistry of corn stover. The combination of phosphotungstic acid and cellulase will give an efficient approach for increasing the saccharification of cellulose.