Abstract:

The aim of this study was to examine effects of five kinds of carbohydrate metabolic products (ethanol, sodium acetate, sodium lactate, citric acid, glycerin) on astaxanthin production by Phaffia rhodozyma fermentation in shake flask scale and 5 L fermentor scale with glucose as the control. Shake flask fermentation experiments showed that sodium acetate, sodium lactate, and citric acid all exhibited a promotion effect on astaxanthin production, while no obvious effect was found from ethanol and glycerin. Both biomass amount of Phaffia rhodozyma and astaxanthin concentration were increased by low concentrations (2, 1 g/L) of sodium acetate, sodium lactate and citric acid to different extents. When citric acid concentration was 2 g/L, a maximum biomass amount of 5.48 g/L was obtained, which was increased by 50.1% compared the control, and the sodium acetate concentration of 1.54 mg/L yielded a maximum astaxanthin concentration of 1.54 mg/L, which was increased by 20.3% compared with the control. However, enlarged fermentation in a 5 L fermentation revealed that neither sodium acetate nor sodium lactate had a promotion effect on astaxanthin concentration and yield and only citric acid was a promotion factor for astaxanthin procution.

Key words: Phaffia rhodozyma , astaxanthin, carbohydrate metabolic products , fermentation