Optimization of fermentation conditions for carotenoid production in the radiation-resistant strain Deinococcus xibeiensis R13

Deinococcus xibeiensis R13 was isolated from an extreme environment in Xinjiang, China, and can resist gamma-radiation and UV-irradiation. In this study, D. xibeiensis R13 was shown to be capable of efficiently producing carotenoids in culture, and factors influencing its productivity were identified. The maximum carotenoid yield was observed at an initial temperature of 30 °C and pH 7.0 in the presence of fructose, tryptone at a C/N ratio of 1:5, and 10 µM Fe2+. The carotenoid yield under modified culture conditions was 6.64 mg/L after fermentation for 48 h, representing an increase of 84% compared to the original conditions. The biomass reached 7.22 g/L, which was 2.19-fold higher than under non-optimized conditions. The produced carotenoids were extracted from R13 and analyzed by UPLC-MS. This is the first study of carotenoid production by the new strain D. xibeiensis R13, which provides a new source for the microbial fermentation of natural carotenoids, and also provides a good reference for industrial production of other carotenoids and other terpenoid products.