Abstract

Mohammed G. Barghoth, Abd-Elmoez A. Zarea, Said E. Desouky*, Gadallah M. Abu Elreesh, Mohamed Roushdy

ABSTRACT

Polyunsaturated fatty acids (PUFAs) play critical roles in human diets as well as in the prevention and control of several chronic diseases and for improvement of heart and brain functions, so its demand is growing. A ten yeast isolates were isolated from different marine habitats. The ability of these isolates to accumulate intracellular PUFAs was primary screened using Nile red and further screened using Triphenyltetrazolium chloride (TTC) stain at an absorbance of 485 nm. Amongst these isolates, four yeast isolates (namely D1, E2, G2, and W6) were exhibited the best results for PUFAs production. The E2 and W6 isolates showed higher lipid accumulation than G2 and D1 isolates with percent between 25 to more than 35% of the cell area with the Nile red with staining degree of 1.43, 1.30, 1.20, and 1.12, with the TTC dye, respectively. When the isolates were cultured on YPD medium at 25°C, isolate E2 yielded 29.3% lipid per dry biomass, while isolates W6 yielded 26.2%, G2 yielded 25.6%, and D1 yielded 23.4%. These isolates were identified based on phenotypic and genotypic characteristics as Candida parapsilosis E2, Candida parapsilosis D1, Pichia kuriavzevii W6, and Meyerozyma guilliermondii G2. Production of PUFAs was conducted under nitrogen-limited conditions using a shake flask technique. The fatty acids profile analysis showed that the lipid extracted from these strains contained oleic acid (18:1), linoleic acid (18:2), and palmitic acid (C16:0) as the major intracellular fatty acids produced that accounted for 90% of total lipids. Also, these strains displayed (27-32%) saturated fatty acids and produced a significant amount of unsaturated fatty acids ranged between 68 to 73 % of the total fatty acids make them a sustainable source for single-cell oil productionas well as pharmaceutical and nutritional industries.