Efficient Biomass Fractionation via Organosolv for Sustainable Bioenergy Production: A Comprehensive Review

Biomass is a significant renewable feedstock for the generation of bioenergy and a gateway to a shift from fossil fuels to a renewable energy system. Efficient fractionation of biomass into the main components (cellulose, hemicellulose, and lignin) is still a problem due to its complexity. Organosolv fractionation is a recently emerging pretreatment technology that employs organic solvents to selectively fractionate biomass components with high purity. In the present review, organosolv fractionation is thoroughly discussed in the context of solvent selection, use of catalyst, and comparison with other pretreatment processes. Biochemical and thermochemical routes of fractioned biomass to bioenergy are also provided. Systematic search and critical evaluation of the peer-reviewed literature from 2000 to 2024 in scientific databases such as Web of Science, Scopus, and Google Scholar were made for the review. A rigorous screening procedure resulted in the inclusion of 191 relevant articles, concentrating on recent innovations and real-life applications of organosolv fractionation. The findings show that organosolv fractionation enhances the efficiency of biomass conversion and product diversity and adheres to the principles of a circular bioeconomy through the recovery of the solvent and production of valuable bio-based chemicals. Despite its promising characteristics, the process is faced with challenges like high operating costs and low solvent recovery, and, therefore, more research is required to implement it in large-scale processes. This review focuses on the relevance of organosolv fractionation as a clean biomass fractionation process and its potential to be included in future biorefinery systems to allow the transition toward a low-carbon energy era.