Natural surfactant-aided dilute sulfuric acid pretreatment of waste wheat straw to enhance enzymatic hydrolysis efficiency

Traditional surfactants have been reported to enhance enzymatic saccharification of lignocellulose, however, it is important to transfer these findings to a system that uses a high-efficiency and low-toxicity natural surfactant instead. In this work, a novel hybrid method involving use of the natural surfactant (humic acid, HA) during mild acid (H2SO4) pretreatment was developed for waste wheat straw (WWS) biorefinery. The HA was found to help remove lignin up to 40.6%, and hemicellulose up to 96.2%. As a result of these changes, the enzymatic hydrolysis efficiency reached as high as 92.9%. The success of enzymatic digestion was partly attributed to the improved accessibility of cellulose to cellulase and changes in lignocellulose structures. We anticipate that these findings will be used to further evaluate HA as a beneficial surfactant in biorefinery pretreatment processes, and perhaps spur others to identify other natural surfactants that may prove even more effective.

Automated summary

This study developed a novel biorefinery method for waste wheat straw, in which a natural surfactant humic acid was used during acidic pretreatment to enhance enzymatic saccharification efficiency. The success of enzymatic digestion was attributed to improved accessibility of cellulose to cellulase and structural changes in lignocellulose. These findings suggest that humic acid may be a beneficial surfactant in biorefinery processes and could potentially inspire research into other natural surfactants.