Screening and Development of b-Carotene Enriched Phaffia rhodozyma Cell by Culture Media Engineering

摘要

beta-Carotene, a well-known carotenoid, plays an important role in several biological functions, including eye health. Presently 80-90 of carotenoids are obtained either by chemical synthesis or from plant sources, which is a very expensive procedure. Therefore, demand for industrial production of beta-carotene using GRAS (Generally Recognized as Safe) microbes is on the rise. In the present work, beta-carotene production by the yeast Phaffia rhodozyma, which was originally known only for its astaxanthin-producing property, was carried out. For this purpose, we first used mutated P. rhodozyma cells developed by our research lab and giving the highest astaxanthin production. These yeast cells were treated with different concentrations of beta-ionone (40-3000 mu M) on yeast-malt agar media. The addition of beta-ionone (40-200 mu M) resulted in yellow to orange cells after 4 to 6 days of incubation. The cells with pronounced pigmentation were subcultured and grown in optimized media in flasks under shaking. Optimal conditions for beta-carotene production were determined using response surface methodology. Fermentation kinetics showed that beta-carotene accumulation started in P. rhodozyma during the lag phase of growth and reached 750 mu g/g at 144 h during the stationary phase of growth. The GRAS P. rhodozyma cells rich in beta-carotene obtained using the culture media engineering may be used for food and feed applications.