Effect of ultrasonic-assisted extraction method on the oil yield and fatty acid profile of Thraustochytrium multirudimentale and Rhodotorula mucilaginosa

This study aims to examine the effect of ultrasonic-assisted extraction method on the yield of oil and the profile of fatty acid from microalga and yeast. The microalga cultivated was identified genetically as Thraustochytrium multirudimentale MAST-1 and the yeast as Rhodotorula mucilaginosa KAST-1. The oils were extracted from dried biomass by solvents using modified Bligh and Dyer (BD) method. Before the extraction, the material underwent ultrasonication, water bath immersion, and centrifugation for biomass separation from the solvent. Extracted oils were further analyzed for compositions of fatty acid using Gas Chromatography-Mass Spectrometry (GC-MS). An increase in the length of ultrasonication in the Bligh and Dyer method yielded a higher amount of oil. The cell walls disruption using ultrasonication for 60 minutes produced the highest oil yield. The BD’s extraction method was the best for yeast R. mucilaginosa KAST-1 with a yield of 46.3% oil, while the microalga T. multirudimentale MAST-1 gave only 20.6% oil. The fatty acids identified in the microalga oil were palmitic, stearic, oleic, elaidic and pentadecylic acid, while in yeast oil were palmitoleic, palmitic, pentadecylic, margaric, linoleic, elaidic, stearic and erucic acid. Linoleic acid as one of polyunsaturated fatty acid (PUFA) was detected in yeast oil.