Biodiesel production from Mucor circinelloides using ethanol and heteropolyacid in one and two-step transesterification

[Display omitted] •Two approaches for transesterification reaction of filamentous fungus were compared.•Ethanol was used for lipid extraction and acyl acceptor.•Reactions were catalyzed by heteropolyacid impregnated on alumina (H3PMo/Al2O3).•High levels of FAEE (>97%) were attained by both procedures.•Direct transesterification of biomass is simpler and renewable process. Biodiesel production from Mucor circinelloides biomass was investigated by conventional method involving the lipid extraction using ethanol followed by transesterification (two-step process) in comparison with directly producing from the whole biomass without extraction (one-step process). Both processes used solid heteropolyacid catalyst (12-molybdophosphoric acid (H3PMo12O40) support on alumina (Al2O3) under conditions previously set up (200°C for 4h). Either one or two-step process was able to convert the microbial lipids into ethyl esters (FAEE) with high yields (97%), though the former simplifies the production process due to the elimination of an oil extraction step that incurs oil loss. Moreover, to minimize the energy used for dewatering, this method can be also used for transesterification of wet M. circinelloides biomass. Direct transesterification of wet biomass greatly simplifies the process of FAEE production by eliminating the drying and oil extraction steps, making this a renewable and environmental friendly process.