Evaluation of Biomass and Total Carotenoids Content of Deinococcus radiodurans R1 in Response to Different Carbon and Nitrogen Sources

In the present study, the effect of different carbon and nitrogen sources on the microbial biomass and carotenoid production of Deinococcus radiodurans, one of the most radiation-resistant microorganisms, was evaluated using one-factor-at-a-time approach. The antioxidant, cytotoxicity and antibacterial properties of the pigment were also evaluated. The carotenoid pigment had EC50 (Half maximal effective concentration) of 20.19 μg/mL and EC50 = 3.28 mg/mL in the ferric reducing antioxidant power and free radical scavenging assay, respectively. The maximum amount of carotenoid pigment was achieved in the presence of 1g/L glucose (34 mg/L) and 1 g/L yeast extract (28 mg/L). Based on the approach of one factor at a time, the optimal conditions for carotenoid production were obtained as 37 mg/L pigment in culture medium containing 1 g/L glucose carbon source and 1 g/L nitrogen source of yeast extract. Besides, the pigment had no toxic or inhibitory effects on the human fibroblast cell line and two bacteria Staphylococcus epidermidis and Escherichia coli.