Isolation, Identification and Screening of Carotenoid-Producing Strains of Rhodotorula glutinis

An attempt was made to isolate yeast strains from different sources (flowers, trees exudates, fruits and cheese) which have a fast growth rate and high content of carotenoids. Seventy cultures of pigmented yeast were isolated. Forty six yeast isolates were selected and identified by simplified identification method which showed that all isolates belong to Rhodotorula glutinis. These isolates were screened in two steps. Seventeen promising isolates of Rhodotorula glutinis were selected after the primary screening. Then 6 yeast isolates were chosen and passed through the second screening. The most promising isolate (isolated from pin cushion flower, Scabiosa atropurpurea) was selected according to its total carotenoids content expressed as torulene (μg?g–1 and μg?L–1). This isolate was reclassified using a number of morphological, biochemical, and physiological characteristics which revealed that the yeast isolate agree well with those of Rhodotorula glutinis Var. glutinis. Dry biomass, amount and proportion of individual carotenoids and lipid content of the selected identified yeast were determined.