Enhanced biodegradation of sticky deposits through cutinase-lipase synergy in designer cellulosomes

Sticky deposits hinder the recycling of waste paper by causing equipment clogging and poor paper quality. Enzymatic degradation is constrained by poor enzyme stability and limited degradation capacity. Herein, Humicola insolens cutinase and Archeoglobus fulgidus carboxylesterase, were selected to construct a cellulosome-based complex (namely HACOM) to enhance the binding and degradation of sticky deposits and the stability of enzymes. Computational analysis and protein adsorption experiments revealed that the carbohydrate-binding module could interact with the substrate poly (vinyl acetate) (PVAc) through hydrogen bonding, hydrophobic interactions and van der Waals forces. Further, HACOM could entirely degrade the surface layer of PVAc film, leading to the full exposure of its internal structure. Meanwhile, HACOM achieved the strongest degradation efficiency with the highest acetic acid yield of 20.9 mg/L. Overall, HACOM could effectively degrade PVAc with favorable enzymatic stability, providing a technical guideline for the treatment of sticky deposits in wastepaper pulp.