Optimization Of Yeast Culture And Its Effect On Culture In Vitro

Candida tropicalis and Saccharomyces cerevisiae were studied.Yeast culture was prepared by liquid-cultivation and solid-fermentation or liquid-fermentation.The suitbale conditions of liquid-fermentation and solid-fermentation in yeast culture and cell-wall broken were fumbled about rudimently, and the agents that affected the cell-wall broken were tried to find out. Then, the trial in vitro was studied to compare the effect of different yeast culture.The concrete trials and results as follows:1. Opitization of solid fermentationTo optimizate the condition of solid-fermentation, pH of culture medium was adjust to alter the acidity of solid- medium, and the evaluation marker was the number of viral bacteria in yeast culture. The result showed when pH was 5.5 the growth of yeast was the best and the mixed bacteria was inhibited.The CFU of Candida tropicalis and Saccharomyces cerevisiae was respectively 137.96×109/g and 134.62×109/g.2. Opitization of liquid cultivation(1) A trial on temperature for yeast growing was carried out using one-factor design.The OD of cultivation was assayed at 26℃,30℃and 37℃.The results showed that growed after 24h in different temprature, yeast growed best in 30℃.(2) A trial on time for yeast growing was carried out using one-factor design.The OD of cultivation was assayed at every two hours.The results showed that in 30℃yeast growed best after 30h.3. Opitization of cell-wall brokenA 3×4 orthogonal experimental design was used to investigate the effect of temperature(30℃,40℃,50℃和60℃),salt(NaCl 0%,1%,2% and3%)and time (20h,24h,28h and 32h)on cell-wall broken, at the same time, to evaluate the effect of cell-wall broken on the content of vitamin. The result indicated that the best condition for cell-wall broken was 50℃for 28h, the rate of cell-wall broken could reach 80% at least; the rate of vitamin loss in yeast could be the minimun, the loss rate of VitB1 in Candida tropicalis and Saccharomyces cerevisiae was 8.71% and 19.54% respectively, the loss rate of VitB2 was 19.39% and 13.18% respectively, and the loss rate of VitB6 was 6.3% and 3.04% respectively.4. Effect of diffenrent yeast culture on culture in vitro(1) A trial in vitro was carried out to compare the effect of different yeast culture on the...