Isolation and identification of carotenoid-producing Rhodotorula sp. from Pinaceae forest ecosystems and optimization of in vitro carotenoid production.

Yeasts are alternative source of natural carotenoids, a group of colored terpenoids with various market applications. Carotenoid Production by yeast fermentation technology is greatly effective and proposes considerable benefits with large scale production, cost effectiveness and safety. In this study, four pigment-producing yeasts were isolated from forest park soils with the potential to produce carotenoids. Morphological, physiological, biochemical and molecular characterization indicates the isolates belong to Rhodotorula mucilaginosa. Carotenoid production was optimized by small scale cultivation. The optimum condition was 120 h of incubation at pH 6.0, 28 °C, white light irradiation, Yeast Extract Peptone Glycerol medium composed of 10 g/L yeast extract, 20 g/L peptone, 20 ml/L glycerol, yielding maximum content of 223.5 μg/g dry weight. The β-carotene content was confirmed by HPLC and FT-IR. The results suggested that soil yeasts are potential sources of carotenoids that could be utilized as a natural agent for industrial products.