Recent advances in deep eutectic solvent pretreatment for the efficient decomposition and utilization of crop straw biomass

The comprehensive and high-value utilization of crop straw biomass (CSB) is pivotal to advancing sustainable agricultural development and achieving the dual-carbon goals, owing to its low-carbon nature, renewability, and abundance. However, the efficient exploitation of CSB is severely hindered by its structural recalcitrance and heterogeneity, making an effective pretreatment technology to overcome this bottleneck. Deep eutectic solvents (DESs) have been considered as the most promising green solvents for CSB pretreatment, which not only possess excellent properties but also exhibit prominent advantages including low toxicity, low preparation cost, good biodegradability and recyclability. This review elaborates on the latest research progress of the DESs (especially novel supramolecular DESs) in CSB pretreatment. It further summarizes cutting‑edge DES‑coupled pretreatment technologies, machine‑learning‑assisted DES optimization, techno‑economic analysis and life‑cycle assessment for DES‑based biorefinery. Mitigation strategies and future research directions are proposed, including polyol‑assisted suppression of lignin condensation, machine‑learning‑driven DES screening, and multi‑dimensional mechanistic exploration via advanced characterization and theoretical simulations. Moreover, the review summarizes the diverse high-value application pathways of DES-pretreated CSB in the generation of platform chemicals, biofuels and materials. The challenges faced in the scaling-up of DES-based pretreatment technology to industrial applications are analyzed. Frontier research opportunities are also highlighted, encompassing the development of advanced analytical tools, integrated characterization of interactions between lignin and carbohydrates, and artificial intelligence‑driven innovation within biorefinery systems. The review provides a theoretical basis and practical guidance for the development of lignocellulosic biorefinery approaches, and is of great significance for alleviating the global energy crisis and addressing major environmental issues.