Characterization of Pigments consisting of Melanin and Carotenoids from a Planococcus Species

Planococcus sp. CAU13 produces a dark pigment, the identity of which is the focus of this study. Initial extraction methods utilized known procedures for carotenoid extraction, as Planococcus members are known to produce yellow to orange pigmented carotenoids. Extractions were followed by melanin isolation techniques, as the carotenoid methods yielded a yellow, but not the expected dark color. Ultraviolet–visible (UV-Vis) spectroscopy and infrared (IR) spectroscopy were used to characterize the extractions. Analysis found that both carotenoids and melanin are likely present. Genetic analysis supports the presence of both carotenoids and melanin. Portions of a known C-30 carotenoid biosynthetic gene cluster (BGC) are present in CAU13. which produces a type III polyketide synthase (PKSIII); this is a class of enzyme known to produce 1,3,6,8-tetrahydroxynaphthalene (T4HN), the first product in the biosynthetic pathway for DHN-type allomelanin. Multiple experiments verify the hypothesis that a mixture of a carotenoid and melanin are produced by the bacterium Planococcus sp. CAU13.