Optimization of carotenoid production in native Rhodococcus strain using different carbon sources and amino acids

BACKGROUND AND OBJECTIVESmicrobial pigments has been applied in various industries such as food and etc, and these compounds show antimicrobial, anticancer activities because they are less toxic than their synthetic analogs. The actinomycetes genus Rhodococcus is one the most important pigment producing bacteria . The metabolic diversity of Rhodococcus spp. strains have been expanded for their biosynthetic capabilities, which can be used in biofuel generation, metal recovery, and novel drug discovery. This study aims to optimize the production of carotenoid pigment in native strains of Rhodococcus isolated from soil around a manganese mine in Qom City by Aghaei et al.MATERIALS AND METHODSStudy of pigment production in culture media such as TSA, BHI Agar, LB Agar, Bennet Agar, and ISP۵ at different temperatures of ۲۵ °C, ۳۰ °C, and ۳۵ °C; amino acids including aspartic acid, glutamic acid, tryptophan, and tyrosine with concentrations of ۰.۵%, ۱%, and ۱.۵%; different carbon sources including glucose, sucrose, maltose, and lactose with concentrations of ۰/۱۲۵%, ۰/۲۵ %, ۰/۵%, ۱%; and different nitrogen sources consisting of sodium nitrate, ammonium nitrate, beef extract with concentrations of ۰/۵%, ۱%, ۱/۵%; and other factors such as pH (۵, ۶, ۷, ۸) and the rpm of the incubator shakers at ۱۵۰, ۱۸۰, and ۲۰۰ in the native strain of Rhodococcus rhodococcus.RESULTS AND DISCUSSIONIn this research, the medium TSA has been identified as the best medium in terms of the growth of the strain Rhodococcus and the production of its pigment. The statistical analysis showed that the best optimal conditions for the production of carotenoid pigment are: a temperature of ۳۰ °C, an rpm of ۲۰۰, pH = ۷, maltose ۱%, sodium nitrate ۱/۵%, and tryptophan ۱/۵%.CONCLUSIONAccording to the results of this research, Native Rhodococcus rhodochrous isolated can be considered as a good candidate for carotenoid pigment production with biotechnological application in food and pharmaceutical industries.