Pengfei Zhao,Fulong Pu,Changsheng Su,Yefan Wan,Texin Huang,Xuedan Hou,Di Cai
Deep eutectic solvents (DESs) offer a potential opportunity in biomass utilization industries. This work emphasized the impact of hydrogen bond donors (HBD) and acceptors (HBA) on deconstruction and valorization of rice straw. Acidity, alkyl chain length, hydrogen bonding ability and functional groups of HBD and HBA appeared to be important factors affecting the fractionated pulps and lignins, which further influenced ethanol fermentation. Among the candidate DESs, lactic acid/guanidine hydrochloride (LGH) was proved to be the most suitable one due to the excellent delignification and xylan removal. For the downstream fermentation process, 0.47 g g −1 of bioethanol with 0.55 g/L h −1 of productivity can be obtained from the LGH pulp’s hydrolysate. Mass balance showed 302.8 g bioethanol and 119.0 g technical lignin can be co-generated from 1 kg dried rice straw. This “green” valorization strategy offers a promising scheme in biorefinery of lignocelluloses.
Acidified aqueous solutions of different quaternary ammonium salts were tested for pretreating corn stover compared to control solutions, including single acidic solution and acidified NaCl and NH 4 Cl solutions. The results revealed that quaternary ammonium salt solutions were more effective in delignification and cellulose saccharification than the control solutions. The chemical structure of these salts significantly influenced the pretreatment efficacy. Notably, benzyltrimethylammonium chloride (BTMAC), a cost-effective option, exhibited remarkable capabilities. It achieved approximately 90% xylan removal, 86% lignin removal, and a 48-h enzymatic glucose yield of up to 93%. The BTMAC solution proved to be recycled for at least four runs while maintaining satisfactory performance. This work contributes valuable insights into the promising potential of standalone QAS solutions, offering a viable and cost-effective option for biomass pretreatment.