Study On Process Engineering Of The Astaxanthin Fermentation By Phaffia Rhodozyma

Astaxanthin is one kind of carotenoids. Due to its natural characteristic pigme-nting and special biological functions of preventing degenerative dieases in human i.e. cancer, cardiovascular disease, immune-system decline, and scavenging free radi-cals, it has generated considerable interest for food, feed, cosmetic and pharmaceut-ical.Phaffia rhodozyma, a red yeast is considered as a potential candidate used to scale-up industrial production of natural astaxanthin. Batch fermentation process of Phaffia rhodozyma was studied in this paper by using biochemical reaction process technology.Batch fermentation of Phaffia rhodozyma was investigated at different KLa andDO. Four KLa control strategies of the batch astaxanthin fermentation were develop-ed, and the experiment results showed the optimal KLa control strategy of batch astaxanthin fermentation.The effects of initial culture pH ranging from 3.5 to 6.5 on biomass and asta-xanthin concentration by Phaffia rhodozyma were investigated in shake flask ferme-ntation. The optimal pH for cell growth was 6.0, and the optimum pH for astaxan-hin accumulation was 4.0. By using the optimal KLa control strategy, batch fermen-tation of Phaffia rhodozyma was investigated at different pH. Three pH control str-ategies of the batch astaxanthin fermentation were developed. Controlled experimen-ts were given to show the optimal KLa and pH control strategy of batch astaxanth-in fermentation.The time course consumption of glucose, fungal biomass, and astaxanthin accu-mulation were investigated on bioreactor scale. A kinetic model was established in this paper. Calculated result coincided well with experimental data.The model couldbe used for good description of batch fermentation process.