Research On The Process Of Ergosterol Fermentation

Ergosterol is the precursor of vitamin D2, and is significant in pharmaceutical and health-care industries. The ergosterol fermentation by Saccharomyces cerevisiae, including the fed-batch methods and the relationships between the physical and environmental paramenters in the process, are discussed in this paper. And the possibilities of industrialization are also analysed.On the basis of some former researches on stains screening and medium selecting, the effects of different fed-batch methods on the growth of yeast cells and the accumulation of ergosterol are studied. The most suitable fed-batch method for this system is determined. The appropriate feeding time, glucose concentration, air rate, the agitation rate and the relationships between the parameters are examined. Dissolved Oxygen (DO) is proved to be an effective control parameter, which can reflects the changes of other important parameters to some content. And the appropriate DO range is determined. For the purpose of industrialization, the effects of different nitrogen sources on fermentation production are experimented. Some researches are also done on the use of recycled medium and wastewater treatment. The best control method is applied to a new yeast strain. The total ergosterol yield increased greatly compared with traditional methods.A new fed-batch based on ethanol control was studied and the ergosterol produced reached1450mg/L with the new fed-batch method.