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

Abstract

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−1vs 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.

Carotenoids from Rhodotorula and Phaffia: yeasts of biotechnological importance

“…The authors suggested that astaxanthin biosynthesis in X. dendrorhous can be stimulated by H 2 O 2 as an antioxidative response. In other article [19] these authors reported that the addition of 9% nhexadecane to the liquid medium for growth of P. rhodozyma leads to increase of carotenoid yield by 58% (14.5 vs. 9.2 mg/l in the control) and oxygen transfer rate by 90%.…”

Increase in the astaxanthin synthase gene (crtS) dose by in vivo DNA fragment assembly in Xanthophyllomyces dendrorhous

“…However, the production of this pigment by wild-type strains is too low (200–400 μg per g of dry yeast) to provide a natural source that is economically competitive with chemical synthesis of this pigment. Therefore, many efforts have attempted to improve the astaxanthin production from X. dendrorhous , including optimization of culture conditions such as glucose concentration [5,6], oxygen levels [6,7], pH [8,9], carbon/nitrogen ratio [10], and light intensities [11], in addition to classic random mutagenesis methods [12-15]. A promising alternative to increase the astaxanthin yield in this yeast is to overexpress the genes involved in carotenoid synthesis (Figure 1) for which several attempts have been performed (For a review see: [16]).…”

A strategic approach for the design and operation of two‐phase partitioning bioscrubbers for the treatment of volatile organic compounds

“…27 Other researchers have also explained this effect in terms of the adsorption of organic liquid droplets at the air-aqueous medium interface forming a rigid film, which in turn causes resistance to oxygen transfer through the air-liquid interface. 23,28,29 With Eqs. 5-8, the theoretical maximum OTR into each phase of the TPPB at 60 L/h of aeration rate and 800 rpm was calculated, and is also shown in Figure 1.…”