Research On Technology Of RNA Production By Continuous Fermentation And Purification Of Can Dida Tropicalis

Ribonucleic acid (RNA) is some kind of important biological macromolecules. It plays a critical role in the expression of genes and the synthesis of biological proteins. With the development of science and technology, RNA is becoming more and more important in different areas, such as medicine, health products and food processing. There is lots of RNA in microorganisms, so factories preferred to make use of the ferment of yeast to produce RNA. For now, Saccharomyce scerevisiae and Candida tropicalis are two important kinds of yeasts for massive production of RNA in factories.Nippon Paper Industries (a Japanese company) uses sulfite pulp as medium to produce yeast by way of bubbling, and it has reached its production capacity to480tons a year; Data shows that Fujian Zhen’ao Company uses sugarcane molasses as carbon source to produce high nuclear yeast by way of airlifting. And the dilution rate of broth was maintained at about0.66h"’; At the same time, the concentration of dry yeast bacteria is11～12g/L with14to15percent of RNA. It could produce200tons of RNA:but when compared with the Japanese company, there is still a giant gap between them. It is needless to say that it is very urgent that we have to improve the efficiency and the quality of RNA production. Only by the way of improving products’ competencies, could we change the situation of RNA production and compete with the world’s finest company.In this paper, firstly we screened one one Candida tropicalis. Secondly we optimized its medium by use of Univariate Orthogona. After that, we got concentration of the thallus up to16～19g/L; And the percentage of RNA wais12to14percent.We have explored the technology to optimize the production of RNA in this paper. Through the fermentation of Candida tropicalis, we did a research to find out the effects of PH, dissolved oxygen, fermentation temperature, different dilution rates continuous fermentation,and other factors on the growth of Candida tropicalis metabolism and RNA production. It turned out that the optimal condition for high nuclear yeast was as follows:Ph was4. DO rate was30%, and the temperature was32-33degree:During batch fermentation, when the sugar concentration of medium was40g/L. the highest concentration of dry yeast bacteria was19.9g/L. the percentage of RNA was up to about13%, and the rate of sugar conversion was48.5%; Under these circumstances, when we used the way of mechanical stirring in a30M3tank for continuous fermentation with the dilution rate at0.3～0.5h-1, the percentage of RNA was up to12-14%, the concentration of dry yeast bacteria was18～21.3g/L and the rate of sugar conversion was about50%. Finally, by the use of mechanical stirring in a tank for continuous fermentation we found new technology to use Candida tropicalis to produce RNA. It not only increased the amount of bacterial and production of RNA, but also simplify the whole procedures, reduce the labor and production costs and improve production efficiency.This paper did a research on the effects of different factors on RNA production rate, such as the concentration of NaOH, extraction time, extraction temperature, concentration of yeast. Finally the optimal option to get RNA came out-that was to produce RNA with Candida tropicalis by the way of dilute alkali. When compared with the way of strong salt, we came to the conclusion that the purity of RNA by the way of dilute alkali was high. At the same time, the environmental pollution was less and this method was suitable for massive production.