Phosphotungstic acid assisted with neutral deep eutectic solvent boost corn straw pretreatment for enzymatic saccharification and lignin extraction

Abstract

In this study, the eco-friendly heteropoly acids-phosphotungstic acid (PTA) was chosen as a catalyst to assist neutral deep eutectic solvents (DESs) for deconstructing corn straw. The reactions were performed with a shorter time at 110–150 °C than other DES system. The results revealed that most of the lignin (86.1 %) and hemicellulose (89.7 %) were removed while cellulose was obtained in high yields (88.9–94.3 %). Benefiting from the removal of hemicellulose and lignin, the enzymatic digestibility of pretreated materials was noticeably boosted to 94.4 %, which was 5.3-fold higher than the untreated corn straw. Meanwhile, the regenerated lignin nanoparticle was acquired with a relatively high purity (more than 85 wt%), low and homogeneous molecular weight (5669−2437 g/mol). Furthermore, the PTA/DES demonstrated excellent cycle performance. Overall, technically feasible PTA catalyzed DES pretreatment presented in-depth analysis for effective deconstruction of corn straw recalcitrance for crops valorization in the future.