Recovery and Reuse of Deep Eutectic Solvents in Lignocellulosic Biomass Pretreatment: A Review in the Context of Circular Economy

Abstract

ABSTRACT: Lignocellulosic biomass, abundant and renewable, is a fundamental feedstock that can be explored for the production of bioproducts in a circular economy context, but its complex structure requires pretreatment to be valorized. Notably, conventional methods are generally limited by harsh conditions and the generation of toxic byproducts. Deep Eutectic Solvents (DES) emerge as a promising alternative, aligned with green chemistry, due to their ability to act selectively under mild conditions. They solubilize lignin and hemicellulose, exposing the cellulose for enzymatic saccharification. However, the large-scale viability of using DES critically depends on their recovery and reuse. This review article analyzes DES recovery strategies, discussing challenges such as their high viscosity and low volatility, aligned with the field of industrial biotechnology. Emphasis is given to methods such as antisolvent precipitation, membrane separation, and electrochemical techniques, highlighting that recovery is essential to reduce costs and enable circularity, consolidating DES as a key technology for a sustainable biorefinery.