Isolation and characterization of a rare polar carotenoid 1’-OH-4-keto-ϒ-carotene from an indigenously isolated Rhodococcus kroppenstedtii MH715196

Abstract

The catabolic diversity and biocatalytic potential in members of genus Rhodococcus makes it an ideal industrial workhouse for metabolite production. Despite their applicability, Rhodococci are least explored for carotenoids, located in their cell membrane. The goal of the present study was to identify the carotenoids of Rhodococcus kroppenstedtii MH715196. UV-Vis spectral data and molecular mass estimates showed that the principal carotenoid extracted from R. kroppenstedtii MH715196 was 1’-OH-4-keto-ϒ-carotene. Biosynthetic route of 1’-OH-4-keto-ϒ-carotene in R. kroppenstedtii MH715196 was postulated on the basis of molecular mass estimates in co-relation with putative carotenoid biosynthetic genes identified in the genome of the reference strains of R. kroppenstedtii. Three key enzymes, were then considered for phylogenetic analysis to establish the phylogenetic relationship across the Rhodococcus genus leading the way for carotenoid identification in other Rhodococcus species. The present study would be the first report on identification of a rare polar carotenoid from R. kroppenstedtii MH715196 which could be potentially explored as a food colorant in hydrophilic food matrices like jams, jellies, beverages etc.