Influence of different fed-batch fermentation modes on astaxanthin production with two Phaffia rhodozyma strains

Abstract:

[Objective] Several fed-batch fermentation modes were studied to investigate the effect on cell growth and astaxanthin synthesis of Phaffia rhodozyma. [Methods] Biomass, astaxanthin concentration and residual sugar concentration were detected when two Phaffia rhodozyma strains (JMU-VDL668 and JMU-MVP14) were fermented in 7 L bioreactor by batch and fed-batch culture. [Results] The highest biomass (64.6 g/L) of Phaffia rhodozyma JMU-VDL668, which was more than 2.2 times of batch culture, was obtained from DO-stat feeding culture; and pH-stat feeding culture brought the highest astaxanthin concentration (20.6 mg/L), which was 1.5 times of batch culture. Differently with the results of Phaffia rhodozyma JMU-VDL668, the highest astaxanthin concentration (414.1 mg/L) of Phaffia rhodozyma JMU-MVP14 was obtained by Pulse-fed culture, which increased by 200.2% compared with batch fermentation. Actually, biomass (38.5 g/L) and astaxanthin concentration (403.2 mg/L) were also improved significantly when DO-stat feeding culture was used, increased by 133.1% and 192.3% compared with batch fermentation respectively. [Conclusion] The production of astaxanthin had a significant effect due to different fed-batch fermentation modes. What’s more, the highest astaxanthin concentration of Phaffia rhodozyma JMU-VDL668 was obtained by pH-stat feeding culture while Pulse-fed culture was optimal for Phaffia rhodozyma JMU-MVP14 to product astaxanthin.

Key words:Phaffia rhodozyma, Astaxanthin, Fermentation, Fed-batch process