Halorubrum sp. TBZ112, an Extremely Halophilic Carotenoid- Producing Archaeon Isolated from Urmia Lake

Background: Carotenoids are organic pigments with substantial applications in neutraceuticals, pharmaceuticals, cosmetics and food industries. Considering the importance of carotenoids, we aimed to isolate and identify a carotenoid-producing microorganism in the present study.

Methods: Gram-negative, aerobic and rod-shaped archaeon, Halorubrum sp. TBZ112 (KCTC 4203 and IBRC-M 10773) producing carotenoids with circle and red colonies were isolated from Urmia Lake in Northwest Iran. Phenotypic characterization and molecular identification of isolate were also conducted. In order to study the ability of TBZ112 to produce carotenoids as well as the production profile, carotenoids were extracted using acetone-methanol solution (7:3 v/v). Then, the carotenoid content of the extract was evaluated using UV spectroscopy and thin-layer chromatography (TLC). The carotenoid profile was analyzed using liquid chromatography-mass spectrometry (LC-MS) techniques.

Results: The 16S rRNA analysis showed that TBZ112 had the highest similarity with Halorubrum chaoviator Halo-G*T (99.78%). The total carotenoid content of strain TBZ112 was found to be 11.7 mg/l. The LC-MS analytical results indicated that carotenoids that were produced included bacterioruberin, lycopene and β-carotene. Among them, bacterioruberin was predominant.

Conclusion: Consequently, we can suggest that future studies should investigate this new and natural source for producing carotenoids.