Statistical optimization of levulinic acid and formic acid production from lipid-extracted residue of Chlorella vulgaris

Abstract Microalgae represent a sustainable feedstock for producing biofuels and biomaterials. In this work, levulinic acid (LA) and formic acid (FA) were produced by catalytic hydrothermal conversion of the lipid-extracted residue of Chlorella vulgaris as a renewable bioresource. Following statistical optimization using a Box–Behnken design, yields of 39.27% LA and 22.06% FA were achieved from 5% biomass treated with 0.95 M HCl at 170 °C for 30 min. In conclusion, lipid-extracted microalgal residue and a Bronsted acid catalyst are useful for producing LA and FA.