Studies On The Sifting Of Marine Yeasts As Protein-rich Diet For Aquaculture

Marine yeast is a common kind of fungi in seawater and is viewed as an important single-cell protein source. In present studies, strains of marine yeasts rich in protein were isolated and selected to provide for further studies and utilization in aquaculture. (1)Seawater samples were collected from Chinese seas and marine yeasts were isolated. All of the strains of isolated yeasts were preserved as yeast seeds which can provide for the next research steps; (2) Gross chemical composition of the isolated yeasts were tested to sift the strains with high protein yield, namely the strains of 3, 32 and 33. Then the amino acids and the fatty acids composition of the selected yeasts were tested to evaluate the food value for aquaculture. The results indicated that the amino acids composition model of the selected yeasts was the same as that the literature reported. This makes the selected yeasts suitable foods for aquaculture; (3) Experiments which scallop juveniles were fed on the selected yeasts were conducted to assure that the marine yeast foods were security and satisfactory. The results showed that substitution of a live algal diet with less than 50% yeast cells could attain the same results as the algal-fed control's results;(4) By using the traditional methods, three selected marine yeasts were respectively identified as Debaryomyces sp. for 3, Kluyveromyces sp. for 32 and Ambrosiozyma sp. for 33; (5) In order to optimize the culture conditions of the selected yeasts, the physiology characteristics, such as PH, salinity and temperature, were optimized.