ISOLATION AND CHARACTERIZATION OF OLEAGINOUS MARINE YEAST PRODUCING OF FATTY ACIDS

Document Type : Original Article

Author

Department of Botany and Microbiology, Faculty of Science, Al-Azhar University, 11884 Nasr, Cairo, Egypt.

Abstract

Because of the limitation of lipid sources from animal and plant, there are great interest searches to finding new alternative lipid sources such as microbial cells that can be used as a key player in different applications such as biodiesel production as well as pharmaceutical and food industries. Therefore, ten sediment and seawater samples were collected from different marine environments for oleaginous yeast isolation purposes. A total of 20 yeast isolates were obtained and screened to accumulate intracellular fatty acids using Nile red staining under a fluorescence microscope as well as Triphenyltetrazolium chloride (TTC) dye at A485nm. Amongst all isolates, two yeast isolates namely C5, and L4 have exhibited the best results for cellular lipid content accumulation. They showed the highest potentiality of lipid accumulation from 14.3 to 15.1gl-1, respectively of dry mass and the percent of lipid content appeared from 25.4 to 28.2%, respectively when cultured on YPD medium at 25°C. Based on phenotypic and genotypic criteria these isolates were identified as Candida parapsilosis C5 and Cryptococcus albidus L4. The study of fatty acids profile composition of these isolates showed that linoleic acid (C18:2), gama-Linolenic acid (C18), oleic acid (C18:1), stearic acid (C18:0), and palmitic acid (C16:0) are the main fatty acids produced that similar to those present in plant oils. The main fatty acids obtained by both strains represent ≃76 % and 91% for isolate C5 and L4, respectively. Also, these strains displayed 68-70% of unsaturated fatty acids and produced an appropriate amount of saturated fatty acids ranged between 30.5 to 32 % of the total fatty acids make these strains a suitable solution to solve many global problems related to dietary supplements, diseases treatment, and energy renewable sources such as biodiesel production.

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