Fermentaton process for preparation of RNA from Candida tropicalis

In this study,effects of the pH,dissolved oxygen (DO) and reducing sugar concentration,high density batch fermentation and high density continuous fermentation on RNA production and reducing sugar conversion rate (g-DCW/g-Glucose) were investigated by the fermentation of Candida tropicalis.It was found that the optimal condition was of pH 4 and DO of 30%.In batch fermentation,19.5 g/L of dry cell concentration was obtained at 40 g/L reducing sugar and the total fermentation time was 8 h and the RNA lever reached 14.3%.In pH-stat fed-batch fermentation by pH and DO at optimal levels,cell concentration reached 35.6 g/L which was 75% higher than that of 19.5 g/L(40 g/L glucose) with the RNA level of 14.2% and reducing sugar conversion rate of 43.5%.The results showed that high density continuous fermentation was similar to high density batch fermentation.