Using strain Rhodotorula mucilaginosa to produce carotenoids using food wastes

•Yeast strain Rhodotorula mucilaginosa F-1 was isolated from a biodiesel plant activated sludge tank.•The optimum pH and temperature for carotenoids synthesis were 5 and 25 °C, respectively.•The main components of produced carotenoids were β-carotene, torulene and torularhodin.•Metal ions supplementation improved the total amount of carotenoids and biomass growth.•Molasses might have potential as acceptable waste due to its low cost and natural carotenoids production ability.

Carotenoids are important natural pigments with antioxidant properties, used extensively as a coloring agent in food, cosmetic additives and health foods. Owing to health concerns, the demand for natural carotenoids has increased significantly in recent years. In this research yeast strain Rhodotorula mucilaginosa F-1 was isolated from a biodiesel plant activated sludge tank for carotenoids biosynthesis. The results revealed the optimum pH and temperature for carotenoids synthesis were 5 and 25 °C, respectively. The percentages of β-carotene, torulene and torularhodin were 28.8%, 48.0% and 23.2%, respectively, under the optimum growth condition (pH5 and 25 °C). After adding metal ions, the total amount of carotenoids and biomass growth were improved. The cell growth and carotenoids synthesis using molasses waste were both better than those using YM medium (control). The carotenoids composition was 23.8% β-carotene, 67.5% torulene and 8.7% torularhodin. Molasses might have potential as acceptable waste due to its low cost and natural carotenoids production ability.

Graphical abstractThin layer chromatography of carotenoids composition of strain Rhodotorula mucilaginosa F-1 without (A) and with (B) chelation and the color. The main pigments produced by the isolated yeast Rhodotorula mucilaginosa are β-carotene (I), torulene (II) and torularhodin (III).Figure optionsDownload full-size imageDownload as PowerPoint slide