Integrated twin-screw extrusion and organosolv pretreatment efficiently enhances cellulose-to-glucose conversion and lignin recovery from corn cobs

Abstract

Efficient conversion of lignocellulosic biomass into bioproducts depends on optimized pretreatment strategies that enhance the accessibility of structural macromolecules. However, individual methods often face limitations regarding cellulose-to-glucose conversion and lignin recovery. This study evaluated an integrated approach combining twin-screw extrusion, organosolv fractionation, and enzymatic hydrolysis using corn cobs as feedstock. A factorial design applied to the extrusion process identified optimal conditions (144 °C, 11 rpm), resulting in a cellulose-to-glucose conversion of 92.6 wt% after enzymatic hydrolysis. In the subsequent organosolv step, treatment time was the most influential factor for improving cellulose digestibility. A second factorial design identified optimal conditions (60 min, 20.1 wt% solids), yielding the highest glucose conversion (93.0 ± 1.2 wt%) and enabling recovery of 45.4% of the solubilized lignin. Additionally, increasing solids loading from 10 to 15 wt% during enzymatic hydrolysis improved glucose productivity by 23.7%. These findings demonstrate that integrating twin-screw extrusion and organosolv pretreatment effectively enhances sustainable valorization of corn cobs.