Integrated approach for cellulosic ethanol and succinic acid production: Gamma valerolactone-based pretreatment and co-fermentation of peanut shells

The inability to utilize pentose poses as a significant limitation to the production of cellulosic ethanol. To attain efficient raw material conversion and mitigate carbon dioxide emissions during cellulosic ethanol synthesis, a integrated approach focused on the co-processing of ethanol and succinic acid (SA) from peanut shells was proposed. The results demonstrated that the GVL system, containing 30 % water and catalyzed by dilute sulfuric acid, exhibited remarkable efficiency in pretreatment, boosting glucose yield sixfold relative to the untreated raw material. Under optimal conditions of 82 mM sulfuric acid, 141 °C, 56 min, and a solid-to-liquid ratio of 0.07, the glucose yield of the pretreated peanut shell reached 79.0 ± 0.22 %. Through recycling the pretreatment solvent, Tween 80-assisted enzymatic catalysis, and coupling of saccharification and co-fermentation processes, the complete utilization of lignocellulosic feedstocks and sustainable production of high titers of SA (86.1 g/kg) and ethanol (66.4 g/kg) were achieved. This study developed a novel integrated procedure for the efficient co-production of SA and ethanol from peanut shells, offering a new perspective for the efficient biorefinery of lignocellulosic biomass.