Exogenous compounds addition in thraustochytrid fermentation and sulfur polymerization of microbial oil to achieve plant-oil like fatty acid profile

Abstract: Thraustochytrids are marine protists known for their ability to produce high amounts of oil content of their dry cell weight. The objective of this study is to tune the thraustochytrid oil profile via exogenous addition of food safe chemical compounds followed by the sulfur polymerization of the resultant oil to obtain plant-oil like profiles. Maximum lipid content (38%, dry wt. biomass) was achieved at 1% Tween 80 and 0.25 mg/L of Vitamin B12. The fatty acid composition of the transesterified lipid was palmitic acid (C16, 35.7% TFA), stearic acid (C18, 2.1% TFA), and oleic acid (C18:1, 18.7% TFA) as the main components of total FAs, in addition polyunsaturated fatty acids (PUFAs), which were slightly inhibited by the addition of limonene in the fermentation medium. The tuned oil was subjected to sulfur polymerization resulting in the formation of sulfur polymer. The saturated fatty acids (SFAs) and monounsaturated fatty acids (MUFAs) were extracted from the polymer using ethanol and thus, PUFAs separation was achieved. The ethanol-extracted thraustochytrid oil exhibited the presence of SFAs (53% of TFA) and MUFAs (46.6% of TFA) that mimics plant-oil-like FA profiles. This study provides a platform to realise the industrial potential of thraustochytrid oil production to develop plant-like oils.