Diversity of Red Yeasts in Various Regions and Environments of Poland and Biotechnological Potential of the Isolated Strains.

Due to the growing demand for natural carotenoids, researchers have been searching for strains that are capable of efficient synthesis of these compounds. This study tested 114 red yeast strains collected from various natural environments and food specimens in Poland. The strains were isolated by their ability to produce red or yellow pigments in rich nutrient media. According to potential industrial significance of the carotenoids, both their total production and share of individual carotenoids (β-carotene, γ-carotene, torulene, and torularhodin) were analyzed. The total content of carotenoid pigments in the yeast dry matter ranged from 13.88 to 406.50 µg/g, and the percentages of individual carotenoids highly varied among the strains. Most of the yeast isolates synthesized torulene at the highest amount. Among the studied strains, isolates with a total carotenoid content in biomass greater than 200 µg/g and those containing more than 60% torularhodin were selected for identification (48 strains). The identified strains belonged to six genera: Rhodotorula, Sporidiobolus, Sporobolomyces, Buckleyzyma, Cystofilobasidium, and Erythrobasidium. The largest number of isolates belonged to Rhodotorula babjevae (18), Rhodotorula mucilaginosa (7), Sporidiobolus pararoseus (4), and Rhodotorula glutinis (4).