Biomass pretreatment is considered a key step in the 2nd generation biofuel production from lignocellulosic biomass. Research on conventional biomass pretreatment solvents has mainly been focused on carbohydrate conversion efficiency, while their hazardousness and/or carbon intensity were not comprehensively considered. Recent sustainability issues request further consideration for eco-friendly and sustainable alternatives like biomass-derived solvents. Carbohydrate and lignin-derived solvents have been proposed and investigated as green alternatives in many biomass processes. In this review, the applications of different types of biomass pretreatment solvents, including organic, ionic liquid, and deep eutectic solvents, are thoroughly discussed. The role of water as a co-solvent in these pretreatment processes is also reviewed. Finally, current research challenges and prospects of utilizing biomass-derived pretreatment solvents for pretreatment are discussed. Given bioethanol's market potential and increasing public awareness about environmental concerns, it will be a priority adopting sustainable and green biomass pretreatment solvents in biorefinery.

生物质预处理被认为是从木质纤维素生物质生产第二代生物燃料的关键步骤。传统生物质预处理溶剂的研究主要集中在碳水化合物的转化效率上，而没有综合考虑其危害性和/或碳强度。最近的可持续性问题要求进一步考虑生态友好和可持续的替代品，如生物质衍生溶剂。已经提出并研究了碳水化合物和木质素衍生溶剂作为许多生物质过程中的绿色替代品。在这篇综述中，对不同类型的生物质预处理溶剂（包括有机溶剂、离子液体和低共熔溶剂）的应用进行了深入讨论。还回顾了水作为共溶剂在这些预处理过程中的作用。最后，讨论了利用生物质衍生预处理溶剂进行预处理的当前研究挑战和前景。鉴于生物乙醇的市场潜力和公众对环境问题的认识不断提高，在生物精炼厂中优先采用可持续和绿色的生物质预处理溶剂。