Biosynthesis, characterization and enzymatic transesterification of single cell oil of Mucor circinelloides - A sustainable pathway for biofuel production

The filamentous fungus Mucor circinelloides URM 4182 was tested to determine its ability to produce single-cell oil suitable for obtaining biodiesel. Cell growth and lipid accumulation were investigated in a medium containing glucose as the main carbon source. A microwave-assisted ethanol extraction technique (microwave power <= 200 W, 50-60 degrees C) was established and applied to lipid extraction from the fungal hyphae to obtain high lipid concentration (44% wt) of the dry biomass, which was considerably higher than the quantity obtained by classical solvent methods. The lipid profile showed a considerable amount of oleic acid (39.3% wt), palmitic acid (22.2% wt) and gamma-linoleic acid (10.8% wt). Biodiesel was produced by transesterification of the single-cell oil with ethanol using a immobilized lipase from Candida antarctica (Novozym (R) 435) as the catalyst. 1H NMR and HPLC analyses confirmed conversion of 93% of the single-cell oil from M. circinelloides into ethyl esters (FAEE). (C) 2015 Elsevier Ltd. All rights reserved.