Process intensification strategies for green solvent mediated biomass pretreatment

Demonstrated to be highly effective for lignocellulosic biomass pretreatment, deep eutectic solvent (DES) has attracted increasing attention owing to its advantages of simple synthesis, relatively low chemical cost, and better biocompatibility as compared to certain ionic liquids. Here we provide a critical review of the status of the design/selection of DES for the pretreatment of biomass feedstocks with an emphasis on the process intensification strategies: 1) integration of microwave, ultrasound, and high solid extrusion for pretreating biomass, 2) one-pot DES pretreatment, enzymatic hydrolysis, and fermentation, 3) strategies for DES recycling and product recovery; and 4) recent progress on molecular simulations toward understanding the interactions between DES and biomass compounds such as lignin and cellulose. Lastly, we provide perspectives toward cost-effective, continuous, high-solid, environmental-benign, and industrial-relevant applications and point to future research directions to address the challenges associated with DES pretreatment.

Automated summary

This article provides a critical review of the application of deep eutectic solvent (DES) in lignocellulosic biomass pretreatment, focusing on process intensification strategies such as the integration of microwave, ultrasound, and high solid extrusion, one-pot DES pretreatment, enzymatic hydrolysis, and fermentation, as well as DES recycling and product recovery. It also discusses recent progress on molecular simulations to understand the interactions between DES and biomass compounds. The article concludes with perspectives on cost-effective, continuous, high-solid, environmentally friendly, and industrially relevant applications of DES pretreatment, as well as future research directions and challenges.