Surfactant-aided acid glycerol pretreatment of sugarcane bagasse: Dual benefits of substrate and lignin modifications for improved enzymatic hydrolysis

This study introduces a surfactant-aided acid-glycerol pretreatment approach for sugarcane bagasse (SCB) that simultaneously modifies the substrate and lignin properties, leading to enhanced enzymatic hydrolysis. Substrates pretreated with surfactants (PEG 4000, Tween 80, Triton-X 100) exhibited a 41.0%–52.0 % increase in glucose yield after enzymatic hydrolysis. Particularly, Tween 80 and Triton-X 100 effectively altered the substrate structure, increasing surface area and pore volume by 43.3%–72.6 % and 43.0%–62.1 %, respectively. Additionally, the surfactants were found to graft into lignin through etherification, resulting in the reduction of the phenolic hydroxyl groups of the lignin by 12.5%–23.0 %. The reduction in these groups led to an increase in the hydrophilicity of the lignin, thus mitigating non-productive adsorption between lignin and enzymes. Density functional theory calculations were also undertaken to provide theoretical evidence of strong hydrogen bonding interactions and more pronounced interaction energy between lignin and surfactants. Furthermore, correlation analysis indicated that the reduction in non-productive adsorption due to lignin modification contributed more to the enhanced enzymatic hydrolysis than the structural properties of the substrates. Overall, this study highlights the significant benefits of integrating surfactants into acid-glycerol pretreatment for enzyme-mediated lignocellulosic sugar platform biorefinery.