Isolation and identification of Candida Orthopsilosi SAGSGC as oleaginous yeast in perch fish by using ribosomal gene and optimization of oil and biomass production

With respect to the human need for functional food and the importance of long-chain polyunsaturated fatty acids as a functional food, identifying the rich resources of fatty acids greatly attract of interest of scientists. Based on this studies, it is found that microorganisms especially yeast species are rich resources of unsaturated fatty acids. In the present study, yeast samples of perch fish, which has the ability of oil production, were isolated and then their ribosomal DNA were used to identify the yeast species. According to the phylogenetic tree, it was known that the yeast species isolated from the gills of perch fish was Candida Orthopsilosi SAKSG. The response surface method showed that the highest oil content (26.3) was achived in media that had 50 g/L glucose and 5 g/L yeast extract. Moreover, maximum amount of biomass (1.16%) was obtained in medium with 46.16 g/L f glucose and 19.67 g/L yeast extract. It is notable that reduction in temperature treatment was led to improve unsaturated oil increment in this microbial lipid up to 24 percentages. reduction of temperature at the end of the fermentation time concide with rising in unsaturated fatty acids with long fatty acid more than 20 carbon, while when temperature was increased from the beginning of the process, structural unsaturated fatty acids such as linoleic and linolenic acid were increased.