Sustainable Valorization of Lignocellulose: A Prospective Life Cycle Assessment of Deep Eutectic Solvent-Based Processes and Economic Viability

The sustainable conversion of lignocellulosic biomass into high-value biobased products is a key low-carbon strategy to address global energy and environmental challenges. Deep eutectic solvents (DES) have emerged as green, tunable media for biomass pretreatment, but their environmental performance and scalability remain underexplored. This study applies a prospective life cycle assessment (pLCA) to a scaled-up multicomponent DES system based on volatile fatty acid (VFA) formulations. Laboratory-scale data were extrapolated through scale-up modeling, learning curves, and scenario analysis to simulate industrial conditions. Environmental impacts of the scaled-up system were compared to laboratory-scale and three conventional pretreatment technologies to assess trade-offs and feasibility. Results show that, with solvent recovery, the scaled DES system reduces environmental impacts by at least 67% across all midpoint categories and outperforms traditional methods. Monetization impact and economic analysis confirm its feasibility, showing a risk index below 0.65 and lower costs than binary DES systems, demonstrating superior environmental and economic potential. Sensitivity analysis highlights DES recovery as a key driver: increasing recovery from 50 to 90% cuts impacts by approximately 70%, underscoring its importance. This study delivers the first pLCA of a scaled multicomponent DES pretreatment, highlighting its environmental-economic trade-offs and supporting its sustainable industrial potential.