Use of n ‐hexadecane as an oxygen vector to improve Phaffia rhodozyma growth and carotenoid production in shake‐flask cultures

Aims:  To identify beneficial oxygen vectors for Phaffia rhodozyma in liquid cultures, and to evaluate their use to improve the oxygen transfer and carotenoid production in the yeast cultures. Methods and Results:  Several liquid hydrocarbons were tested as oxygen vectors for improving the yeast growth and carotenoid production in shake‐flask cultures of P. rhodozyma . While all nontoxic organic liquids (Log P: ≥5·6) showed a positive effect, n ‐hexadecane was proved to be the most beneficial for the yeast growth and carotenoid production. The addition of 9% (v/v) n ‐hexadecane to the liquid medium at the time of inoculation was found to be optimal, increasing the carotenoid yield by 58% (14·5 mg l −1 vs 9·2 g l −1 in the control) and the oxygen transfer rate (OTR) by 90%. Conclusions:  The addition of n ‐hexadecane to shake‐flask cultures of P. rhodozyma significantly improved the oxygen transfer in culture, thus increasing the carotenoid production. Significance and Impact of the Study:  Use of organic oxygen vectors such as n ‐hexadecane may be a simple and useful means for enhancing oxygen transfer and carotenoid production in liquid fermentation of P. rhodozyma .