Isolation and Identification of Canthaxanthin from Micrococcus roseus

Area of Science:

• Microbiology
• Natural Product Chemistry
• Pigment Analysis

Background:

• Micrococcus roseus is a bacterium known to produce colored compounds.
• Carotenoids are a class of natural pigments with diverse biological roles.
• The specific pigment responsible for the color in M. roseus was not previously identified.

Purpose of the Study:

• To isolate and identify the principal colored carotenoid pigment from Micrococcus roseus.
• To determine the chemical structure of the isolated pigment.
• To establish whether the pigment is a known compound and if it has been previously identified in bacterial sources.

Main Methods:

• Purification of the pigment using solvent partitioning, column chromatography, and thin-layer chromatography.
• Characterization of the pigment through absorption spectra, partition coefficients, and infrared spectra.
• Chemical modification of the pigment via reduction and dehydration, followed by spectral analysis of the derivatives.

Main Results:

• The principal colored carotenoid of Micrococcus roseus was successfully isolated and purified.
• Spectral and partition coefficient data indicated the pigment was a diketo derivative of beta-carotene.
• Further analysis of derivatives confirmed the pigment's identity as canthaxanthin (4',4'-diketo-beta-carotene).
• The pigment was identified as an all-trans isomer and not an ester in M. roseus.

Conclusions:

• The colored pigment isolated from Micrococcus roseus is canthaxanthin.
• This study represents the first identification of canthaxanthin as a bacterial pigment.
• Canthaxanthin from M. roseus exists as an all-trans isomer and not as an ester.