Synergistic enhancement of enzymatic hydrolysis by DES-CTAB pretreatment via mitigating lignin-induced non-productive cellulase adsorption

To address low cellulose conversion efficiency stemming from recalcitrance of lignocellulose, a novel ternary DES-CTAB (deep eutectic solvents- cetyltrimethylammonium bromide) system was developed by synergistically integrating CTAB with DES. And related underlying mechanisms were elucidated. Pretreated residues properties, lignin structure and lignin-cellulase interaction were systematically characterized. Results indicated that the DES-CTAB pretreatment removed 83.21 % of hemicellulose and 79.37 % of lignin while preserving 88.69 % of cellulose during pretreatment at 150 °C for 1 h. Enzymatic hydrolysis efficiency was enhanced to 71.58 %, representing 36.55 % improvement compared with DES pretreatment. It was revealed that CTAB reduced lignin hydrophobicity, inhibited β-O-4 cleavage and phenolic hydroxyl group formation, and mitigated non-productive cellulase adsorp-tion to residual lignin. Fluorescence spectroscopy analysis confirmed that CTAB significantly weakened lignin-enzyme interactions, as evidenced by a 2–3 order of magnitude decreased in the binding constant (K a ) between cellulase and residual lignin. The results could provide theoretical support for green and efficient biomass pretreatment technologies development.