Effect of solvents and oil content on direct transesterification of wet oil-bearing microalgal biomass of Chlorella vulgaris ESP-31 for biodiesel synthesis using immobilized lipase as the biocatalyst

► A microalga isolate Chlorella vulgaris ESP-31 can accumulate up to 63% lipid content. ► Direct transesterification of wet microalgal biomass was used to produce biodiesel. ► Optimal solvent and biocatalyst loading for the direct transesterification was identified. ► Efficiency of direct transesterification is affected by the microalga's lipid content.