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    Isolation and identification of two yeast strains from Iranian dairy sources as a potential safe microbial novel food.

  • ZOHRE TAHERI,1 Hossein Askari,2,*
    1. Shahid beheshti University
    2. Shahid beheshti University


  • Introduction: Nowadays, microbial biotechnology is receiving worldwide attention by introducing alternative food sources which are necessary to achieve sustainable food and feed security. Yarrowia lipolytica is a non-pathogenic generally regarded as safe yeast (GRAS) for industrial productions by the American Food and Drug Administration. Yarrowia lipolytica biomass, which is classified in the category ‘Food consisting of, isolated or produced from microorganisms, fungi or algae’ is considered as a novel food and a novel food ingredient and it can be a component of food supplements and a component of selected foods in the form of yeast cells, dried and deprived of metabolic activity. One of the most important obstacles to the industrialization of the Y. lipolytica platform is the lack of naturally versatile strains to make the platform more robust for increased yield and productivity.
  • Methods: in the present study, we attempt to isolate and characterize novel strains of Yarrowia lipolytica from artisanal Iranian dairy products such as kefir, yogurt, and different types of cheeses collected from various 62 regions and climates of Iran through phenotypic procedures and molecular techniques such as restriction analysis of PCR-amplified ITS-5.8S rDNA (ITS-PCR) and sequencing of D1/D2 domain of 26S rRNA encoding gene. One-way analysis of variance was used to compare the mean protein content, lipid production, biomass production, and lipid content in Y.lipolytica isolated strains. Crude protein determined by the Kjeldahl method.. Bligh and Dyer procedure were used for the extraction and quantification of yeasts lipids and Gas chromatography technique was used for the lipid quality assay.
  • Results: 19 isolates Yarrowia lipolytica are identified by Barcoding of the ITS and finally just 8 isolated confirmed as Yarrowia lipolytica by sequencing D1/D2 ribosomal DNA regions. The highest protein concentration of the biomass ranged was 56.21±2.3 % (w/w). The highest lipid content of 66.751 ± 2.441% was attained by two isolated Y. lipolytica and the average amount of unsaturated fatty acids extracted from them was reached about 75% and they showed 80.382%, 80.079% of unsaturated fatty acids, including (72.7%), linoleic (C18:2) and oleic (C18:1) acid.
  • Conclusion: According to the results we can assess our isolated Y. lipolytica and recommended them for production purposes, including food and feed products based on biomass without any viable Y. lipolytica cells in the final product. In future study it is possible to couple the media engineering with this two candidate isolated strain of Y. lipolytica in order to optimize the biomass production in an optimized economical culture medium.
  • Keywords: Microbial food, ITS-PCR, 26S rRNA gene, Yarrowia lipolytica, Iranian dairy products.