Publication

Abstract : The aim of this work was to develop a new green process for simultaneous depolymerization and valorization of lignin into high-value chemicals to meet the requirement of lignocellulosic biorefinery. A new Enzolv process for the delignification of the woody biomass of Melia dubia was developed using thermosolvent stable laccase (LccH) obtained from Hexagonia hirta MSF2. LccH showed enhanced initial activity of 127% and stability in the presence of ethanol, with 122% of its activity retained for 17 h. The process involved steam pretreatment of M. dubia biomass followed by laccase treatment (50 U.mL−1) in the presence of ethanol (2%) at 40 °C for 17 h. A maximum of 48% reduction in lignin and 52% availability of cellulose from woody biomass for further hydrolysis were obtained. Scanning electron microscopic analysis of the biomass revealed significant morphological and structural changes because of the Enzolv process. Significant lignin removal was observed by FT-IR, while an increase in cellulose content with a 20% increase in relative crystallinity compared to untreated biomass was observed by X-ray diffraction. This process also generated high-value chemicals such as benzaldehyde, isothiazole, propionic acid, benzene dicarboxylic acid, vanillin, and isovanillin during delignification.