The Screen Of Lipid Yeast And The Research Of Fermented Product

The microbial lipid is also known as single cell oil (SCO), which is synthesized by yeast, bacteria, algae, molds and other microorganisms by means of using carbohydrate,hydrocarbon and ordinary lipid as carbon source under certain conditions. Among them, the triglyceride is mainly composed of unsaturated fatty acids, fatty acid composition is similar to vegetable oil. Compared with the traditional oil production process, the microbial oil has the advantages of high oil content, low production cost, short production cycle,etc. Facing the nature resource crisis and population problem, measures must be taken to ensure public food health and meat the growing demand for oil, the microbial lipid is a good choice.The paper aims to study the grease producing ability of different yeast under the same conditions, and then screen out which is rich in output and oil, study on the effect of different single factor on the yield of yeast oil, at the same time, study the syncrgistic effect of different factors on the yield of yeast oil, optimize the fermentation process of the production of fat bacteria. Finally, analyze the composition of unsaturated fatty acids in yeast.Chose the Candida albicans, Rhodotorula glutinis and Saccharomyces cerevisiae which were preserved by frozen inclined planes, than activated them, inoculated and activated in the YPD medium, kept temperature constant at 28-30, in the shaking of 120r/min’s speed, cultivated 2 days and make the cell proliferate, and then inoculated in the former spore culture medium, made shaking culture for 4 days which the temperature was 28-30 and the speed was 120r/min, centrifuged 2500r/min of the above mentioned medium for 5min, weighed its wet weight, placed the wet cell at 80 degrees for constant temperature drying, and weighed its dry weight, the measured was that the water content of Candida albicans was 90.15%, the water content of Saccharomyces cerevisiae was 88.57%, the water content of Rhodotorula glutinis was 82.29%, ground dry bacteria to powdery, extracted the crude fat by cable extraction, to measure the content, Candida albicans oil content was 32.15%, the oil content of Saccharomyces cerevisiae was 23.49%, and the oil content of Rhodotorula glutinis was 26.68%, results showed that under the same conditions, Candida albicans had more oil production and more benefit to produce.According to the single factor and orthogonal test can be determined, the optimum technological conditions that Candida albicans produced oil are:Carbon source was glucose, nitrogen source was ammonium sulfate, PH was 6.5, glucose concentration was 6%, temperature was 32, when the metal microelement was manganese, the effect of the experiment was relatively large. Under this condition, made the Biomass as the benchmark, Candida albicans had a greater impact on the oil production and the biomass was bigger.In this thesis, we studied candida fermentated product and studied the urea package legal application in the extraction of candida unsaturated fatty acid. The results showed that the method of urea inclusion has advantages in extracting unsaturated fatty acids as follows:On the one hand, the method is simple and effective. On the other hand, solvent is easy to recycle. In conclusion, it was suitable for extracting the unsaturated fatty acids of microorganism. Combining literature, the optimal conditions for the extraction of unsaturated fatty acids by urea were:The ratio of urea and fatty acids was 3:1, reflux time is 30 min. Under these conditions, the extraction rate of unsaturated fatty acids was 31.7%,8 fatty acids were detected in the bacterial oil, among which the content of the Sixteen and the 10-eighteen were the largest.