F. Sonntag, I. Schmidt, M. Buchhaupt, J. Schrader
In situ extraction is important for highly productive and cost-efficient processes in industrial biotechnology, but it is difficult to establish for intracellularly accumulating carotenoids like β-carotene. In this study, the organic solvent used in aqueous-organic two-phase media exerted a strong effect on the release of β-carotene from recombinant yeast cells. The carotenoid-synthesizing Saccharomyces cerevisiae strain YB/I/E was cultivated in two-liquid-phase media with 20% dodecane or 20% sunflower oil. Up to 0.6 µg/ml β-carotene was released into sunflower oil, but less than 0.1 µg/ml into dodecane, although biocompatibility and solubility of β-carotene is appropriate for both solvents. Addition of linoleic acid, the main component of sunflower oil, to the dodecane phase increased the amount of β-carotene released, indicating that linoleic acid is the component responsible for the β-carotene release into sunflower oil. These findings demonstrate that the effect of the organic solvent should be taken into consideration for further research on in situ extraction of carotenoids.