Enhancing fermentable sugar production from sugarcane bagasse through surfactant-assisted ethylene glycol pretreatment and enzymatic hydrolysis: Reduced temperature and enzyme loading

Abstract

In this study, an efficient coupling surfactant to ethylene glycol pretreatment (EG) and enzymatic hydrolysis of sugarcane bagasse (SCB) was proposed to enhance fermentable sugar production with lower pretreatment energy consumption and reduced enzyme loading. Under optimized conditions, 5 % Tween 80-assisted EG pretreatment of SCB achieved 80.5 % delignification while retaining cellulose (91.6 %) and hemicellulose (81.6 %) content. This led to an enhanced glucose yield of 81.3 %, compared to 65.1 % without Tween 80. The addition of Tween 80 to pretreatment modified residual lignin through etherification, reduced phenolic hydroxyl groups and enhanced hydrophilicity by 23.7 % and 9.4 %, respectively, compared to the lignin sample without Tween 80. Consequently, this modification alleviated non-productive adsorption between lignin and enzymes, improving substrate hydrolyzability. Moreover, when 4.5 % Triton-X 100 was introduced during the hydrolysis of Tween 80-assisted EG-pretreated substrates, a maximum glucose yield of 91.8 % and xylose yield of 92.6 % were achieved. Energy and enzyme cost analyses revealed a reduction of 35 % in pretreatment energy consumption and a 58.8 % decrease in enzyme costs, thanks to the synergistic action of surfactants in EG pretreatment and enzymatic hydrolysis. Overall, integrating surfactants into pretreatment and enzymatic hydrolysis holds promise for highly efficient conversion of SCB into fermentable sugars in enzyme-mediated lignocellulosic biorefineries.