Significant boost in xylose yield and enhanced economic value with one-pot process using deep eutectic solvent for the pretreatment and saccharification of rice straw

Abstract

The conversion of crop wastes into fermentable sugars and other chemicals mediated by deep eutectic solvents (DESs) has attracted significant attention. In this work, lactic acid, the constituents of DES, was proved to be a harmful inhibitor for cellulase during the conversion of rice straw to fermentable sugars. Nevertheless, the study here also demonstrated that depending on conditions, lactic acidic–choline chloride (LC) can be utilized for pretreatment and saccharification in a one-pot (PSOP) process with high sugar release. The PSOP process performed at 120℃ for 3 h, 15% biomass loading, a 0.30 mol/L LC with a 40 FPU enzymes saccharification system, achieved a total sugar yield of 75.7%. This value is significantly higher than the 49.9% yield achieved in traditional solid-liquid separation (SLS) processes due to the excellent xylose yield (75.7%). This high total sugar yield is attributed to the retention of the xylooligosaccharide, which was directly utilized in the PSOP process. In addition, the techno-economic analysis demonstrates the potential feasibility of a LC based PSOP process in industrial application.