Surfactant-Assisted Enzymatic Saccharification of Different Pretreated Sugarcane Bagasse into Reducing Sugar Yield

Abstract Pretreatment method and process conditions significantly affect biomass composition by altering the relative proportions of cellulose, hemicellulose, and lignin, thereby influencing reducing sugar (RS) yield during enzymatic hydrolysis. In this study, the effectiveness of hot water-, acid-, alkali-, and choline chloride (ChCl)-based deep eutectic solvents (containing lactic acid, acetic acid, or formic acid) was compared for sugarcane bagasse (SCB) delignification. The alkali pretreatment method, which achieved the highest delignification (i.e., 65.01%), was further evaluated at NaOH concentrations (1–5% w/v), temperatures (80–120 °C), and reaction times (1–3 h) using a factorial design. SEM, XRD, and FTIR analyses of pretreated SCB indicated an abundance of surface micropores, increased crystallinity, and changes in surface functional groups, suggesting improved delignification and increased cellulose accessibility. The SCB pretreated with 2.5% NaOH at 120 °C for 3 h achieved the highest delignification (91.1%) and RS yield (85.5% w/w) after 72 h of enzymatic saccharification. Though two-way ANOVA suggests NaOH concentration in SCB pretreatment and surfactant amendments (CTAB, Tween 20, PEG, control) in enzymatic hydrolysis as significant factors for RS yield, Holm–Sidak multiple comparison revealed no significant difference among the surfactant pairs ( p > 0.05).