Enhancement of lipid accumulation in oleaginous marine yeast; Candida sp. for biodiesel production and antimicrobial properties

Fatty acids, both free or as part of complex lipids, are essential components of all vital membranes. Thus, the aim of the present study is the production of fatty acids by marine yeast using some natural of low price sources. Marine Candida sp. isolated from SidiBishr, Mediterranean Sea, Egypt, showed the highest capabilities of lipid accumulation by 42.8% in 1.9 gl^-1 dry biomass. Optimization of the fermented conditions for lipid production was carried out by using one factor at time. Molasses and urea as carbon and nitrogen sources showed the highest lipid content 71% in 6 gl^-1 biomass at pH 5, 25^oC and 20% inoculum size, where, lipid accumulation and dry biomass of marine Candida sp. increased by 1.7 and 3.2 fold, respectively. Esterification of the accumulative lipid was performed, resulting in 34 fatty acid methyl esters (FAMEs) detected by Gas chromatographic analysis. Biodiesel properties were estimated showing the Degree of Unsaturation (DU), 98.87; Long Chain Saturation Factor (LCSF), 13.96; Iodine Value (IV), 105.07; Saponification Value (SV), 190.34; the Cetane Number (CN), 57.43; Kinematic Viscosity (υ), 4.52; Density (ρ), 0.87 and the Higher Heating Value (HHV), 40.05. Antibacterial activity of the extracted lipid showed inhibition zone diameters ranged from 10 to 17 mm. Moreover antifungal activity against some pathogens ranged from 50 -100%.