Enhanced Carotenoid Production in Rhodococcus kroppenstedtii S12 using Photoactive Cobalt Ferrite Nanoparticles.

Natural pigments, especially carotenoids, have gained significant attention due to their diverse applications in the food, pharmaceutical, and cosmetic industries. To meet the growing demand for these valuable compounds, there is a pressing need for efficient and cost-effective production strategies. Current efforts focus on the discovery of new bioactive pigment-producing strains from diverse environments and on improving their productivity. Accordingly, this study aimed to isolate and characterize a bacterium capable of producing a bioactive pigment with industrial potential and to investigate the use of nanomaterials, specifically cobalt ferrite nanoparticles (CoFe₂O₄ NPs), to enhance pigment production. Through meticulous screening and isolation techniques, Rhodococcus kroppenstedtii strain S12 was identified as a potential pigment-producing strain. Spectroscopic analyses indicated that the extracted pigment is putatively a carotenoid, specifically tentatively identified as 4-keto-γ-carotene via LC-MS. Additional mass spectral data suggested the presence of other γ-carotene derivatives, including 1'-OH-4-keto-γ-carotene and 1'-[(6-O-octadecanoyl-β-D-glucopyranosyl)oxy]-1',2'-dihydro-β,ψ-caroten-4-one. The incorporation of CoFe