Biocatalysis in Biomass-derived Solvents: The Quest for Fully Sustainable Chemical Processes

The use of biocatalysis for the provision of optically active building blocks and other useful compounds for fine chemicals and pharmaceutical industries is nowadays a mature technology. To further improve the ecological footprints of these applications, there is currently an increasing interest in using biomass-derived solvents for enzyme-catalyzed processes that may be implemented at industrial level on a midterm basis. The rationale behind these concepts would be the final replacement of petroleum-based solvents by more benign, environmentally-friendly, biodegradable, tunable and smart solvents. This review discusses the state-of-the-art on this topic, focusing on recent enzymatic applications reported in deep-eutectic-solvents, 2-methyltetrahydrofuran, glycerol-based solvents, and organic carbonates, among some important relevant cases of biomass-derived solvents from which biocatalytic applications have been assessed. When possible, the connection of these emerging applications with pharmaceutical chemistry will be provided as well. By looking at the topic from a whole-picture perspective, there are already an interesting number of proof-of-concept approaches that properly combine enzyme catalysis and bio-based solvents. Yet, the general impression is that the area is largely unexplored, with plenty of exciting opportunities, and therefore it may be certainly expected that new applications will be developed and reported in the coming years.