Potential Assessment of Oleaginous Fungi for Sustainable Biodiesel Production: Screening, Identification and Lipid Production Optimization

Abstract

The present work, aiming to exploit oleaginous fungi for biodiesel production. Ten fungal strains were isolated from two petroleum polluted soil samples and screened for their abilities to accumulate lipid. Lipid rich three species viz, Aspergillus terreus, Aspergillus niger and Aspergillus avus were found to be the highest lipid producers. Potential isolates were identied at the species level by morphological (macroscopic and microscopic) examination and molecularly conrmed by using 18S rRNA gene sequencing. Improvement of lipid accumulation by optimization of various parameters of culture conditions. The results reported clearly that the most suitable medium conditions for highest lipid production (38.33%) of Aspergillus terreus as the most potent lipid producer composed of 5% sucrose, 0.5 g/L ammonium nitrate with initial pH 6.0, after seven days of incubation in a static condition. The three promising fungal isolates have been taken for fatty acids analysis by gas chromatograph (GC) after transesterication. Fatty acid methyl esters (FAME) prole indicated the presence of higher saturated fatty acid fractions compared to polyunsaturated fatty acids. The total concentration of fatty acids was 107.98, 38.29, and 37.48 mg/100g of lipid accumulated by A. terreus, A. niger and A. avus, respectively. Gas chromatograph analysis of A. terreus lipid indicated that oleic acid (C18:1, 18.51%) was the most abundant fatty acid, followed by stearic acid (C18:0, 15.91%) and Myristic acid (C14:0, 14.64%), respectively. Therefore, fatty acid prole of A. terreus has conrmed its potentiality as feedstock for producing lipid for biodiesel manufacturing.