Systematic solvent selection enables the fractionation of wet microalgal biomass

Wet microalgal biomass was recently proposed as a feedstock to circumvent the energy-intensive drying step in biorefineries. However, solvents commonly applied to extract valuable target compounds from dried biomass are usually less effective when applied on wet biomass. In the present study, we investigated the potential of systematic solvent selection to increase pigment and lipid yields for the extraction of wet Phaeodactylum tricornutum biomass. The solvent selection was guided by a large-scale computational screening approach. Experiments revealed, that 2-butanol - a non-toxic, partially water-miscible solvent - extracted 99.4 wt% of lipids and 82.6 wt % of carotenoids from wet biomass. By using only 2-butanol and water as benign solvents, we developed a biorefinery approach that effectively fractionates wet microalgal biomass under ambient conditions into proteins, carbohydrates, carotenoids and lipids without the need for energy-intensive biomass drying.