Isolation and identification of echinenone from Micrococcus roseus

Area of Science:

• Microbiology
• Natural Product Chemistry

Background:

• Carotenoids are vital pigments with diverse biological roles.
• Echinenone, a keto-carotenoid, is commonly found in algae and invertebrates.
• Bacterial carotenoid production is an area of ongoing research.

Purpose of the Study:

• To isolate and characterize an orange carotenoid pigment from the bacterium Micrococcus roseus.
• To confirm the identity of the pigment using spectroscopic and chromatographic methods.
• To determine if echinenone has been previously identified as a bacterial pigment.

Main Methods:

• Purification of the carotenoid using solvent partitioning, column chromatography, and thin-layer chromatography.
• Spectroscopic analysis (absorption spectra) and determination of partition coefficient.
• Chemical reduction of the purified pigment and comparison with authentic standards.

Main Results:

• An orange carotenoid was successfully isolated from Micrococcus roseus.
• Analysis indicated the pigment was echinenone (4-keto-beta-carotene).
• Reduction yielded isocryptoxanthin (4-hydroxy-beta-carotene), consistent with echinenone's structure.
• Co-chromatography confirmed the identity of the pigment and its reduction product.
• This marks the first reported identification of echinenone as a bacterial pigment.

Conclusions:

• The orange pigment from Micrococcus roseus is identified as echinenone.
• This study provides the first evidence of echinenone production by a bacterium.
• The findings expand the known occurrence of carotenoids in the microbial world.