Microbial oils from oleaginous yeasts are potential alternatives for sustainable biodiesel production. The Mount Makiling Forest Reserve (MMFR) in the Philippines is a tropical rainforest with a megadiverse ecosystem but with limited information on its microbial diversity. This makes it an attractive source of novel and potentially biotechnologically valuable microorganisms. Twenty-two out of 258 yeasts isolated from the barks, roots, canopy leaves, and associated epiphytic plant material of various forest trees in the MMFR, were potentially oleaginous. Using a nitrogen-limited medium containing glucose as a carbon source, BUB8 and NFR6, isolated from the upper bark of a Bagtikan and the fern-root of the Narra tree, respectively, showed the highest biomass and lipid production levels. BUB8 accumulated a higher lipid content than NFR6 when grown in the same medium with glycerol as a carbon source. The fatty acid methyl ester profile of the transmethylated microbial oil produced by BUB8 showed that oleic acid is the dominant species (C18:1 >C16:0 >C18:2 >C18:0 >C14 = C16:1). Finally, phylogenetic analysis of the ITS rDNA region classified BUB8 as a member of the Rhodotorula genus.
Key words: biodiesel, fatty acid methyl esters, microbial oil, oleaginous yeast, Rhodotorula
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