Document Type : Research Article
Department of Microbiology, Qom Branch, Islamic Azad University, Qom, Iran.
In recent years, scientists and researchers from all over the world pay much attention to carotenoid pigments as a substitute for antibiotics and synthetic chemical compounds with antioxidant property and the plants, various microorganisms including bacteria and algae are also capable of producing carotenoid pigments. In this research, the production of antimicrobial and antioxidant carotenoid pigment in native strain of Rhodococcus bacterium was studied and evaluated for the first time in Iran. The activation and growth of the native Rhodococcus rhodochrous isolate was done using cultivation on different culture media including Triptic soy agar, BHI agar, ISP5, Bennett's Agar and LB Agar at 30 ° C. Pigment extraction was carried out with different organic solvents and carotenoid pigment components were analyzed using GC-MS method. Antimicrobial activity of the pigment was examined using Agar well diffusion method and its antioxidant property by DPPH(2,2-diphenyl-1-Picrilhydrazil) method was examined and analyzed by comparing to antioxidant BHT. The best media for growth and pigment production were determined TSA and TSB. The antimicrobial activity of carotenoid pigment was obtained against to staphylococcus aureus and Candida aibicans with 21mm and 35mm in diameter of inhibition zone respectively. Antioxidant activity of pigment was determined at the concentration of 8 mg/ml (75.59181 %).GC-MS analyses of extracted pigment showed compounds with the highest peak area. The results of this research indicated that native Rhodococcus rhodochrous strain as a non-pathogenic soil bacterium can be candidate biological source with antimicrobial and antioxidant activity for various applications in farmaucidal and biotechnological products.