Improving carotenoid pigments production in Rhodotorula mucilaginosa using UV irradiation.
Rhodotorula yeasts were isolated from various local sources in Damascus, Syria, during 2012 and 2013. Fifty isolates (23 from leaves trees, 13 from different soils, 6 from different meats, 6 from dairy products, 1 pickle and 1 traditional sweet) were identified using API 20C AUX system. Isolated yeasts were classified into three Rhodotorula species: R. mucilaginosa, R. glutinis and R. minuta representing 76%, 20% and 4% of total isolates tested respectively. All isolates were able to produce carotenoid pigments that varied in their quantities ranging from 13.61 μg/g dry biomass for isolate A28 to 658.23 μg/g for isolate A23. The wild strain A23 of R. mucilaginosa was subjected to mutagenesis using UV irradiation at a wavelength of 254 nm. Highest carotenoid production within isolated mutants reached a value of 734.58 μg/g dry biomass after an irradiation period of 4.5 minutes. Overall, UV irradiation