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IDENTIFICATION AND PHYSIOLOGICAL ASPECTS OF A NOVEL CAROTENOID-ENRICHED, METAL-RESISTANT MICROALGA ISOLATED FROM AN ACIDIC RIVER IN HUELVA (SPAIN)1
Version of Record online: 10 MAY 2012
© 2012 Phycological Society of America
Journal of Phycology
Volume 48, Issue 3, pages 607–614, June 2012
How to Cite
Garbayo, I., Torronteras, R., Forján, E., Cuaresma, M., Casal, C., Mogedas, B., Ruiz-Domínguez, M. C., Márquez, C., Vaquero, I., Fuentes-Cordero, J. L., Fuentes, R., González-del-Valle, M. and Vílchez, C. (2012), IDENTIFICATION AND PHYSIOLOGICAL ASPECTS OF A NOVEL CAROTENOID-ENRICHED, METAL-RESISTANT MICROALGA ISOLATED FROM AN ACIDIC RIVER IN HUELVA (SPAIN). Journal of Phycology, 48: 607–614. doi: 10.1111/j.1529-8817.2012.01160.x
Received 19 April 2011. Accepted 18 October 2011.
- Issue online: 1 JUN 2012
- Version of Record online: 10 MAY 2012
- Accepted manuscript online: 4 APR 2012 12:52PM EST
- oxidative stress
A heavy-metal-resistant, carotenoid-enriched novel unicellular microalga was isolated from an acidic river in Huelva, Spain. The isolated ribosomal 18S subunit rDNA sequence showed homology with known sequences from green microalgae, the closest sequence (98% homology) belonging to the genus Coccomyxa. The isolated microalga therefore was an up to now uncultured microalga. The microalga was isolated from Tinto River area (Huelva, Spain), an acidic river that exhibits very low pH (1.7–3.1) with high concentrations of sulfuric acid and heavy metals, including Fe, Cu, Mn, Ni, and Al. Electron micrographs show that the microalga contains a large chloroplast with a presence of lipid droplets, an increased number of starch bodies as well as electron-dense deposits and plastoglobules, the last observed only in iron-exposed cells. Unlike other acidophile microalgae, the isolated microalga showed high growth rates when cultivated photoautotrophycally (up to 0.6 d−1) in a suitable culture medium prepared at our laboratory. The growth was shown to be iron dependent. When the microalga is grown in fluidized bed reactors, the high growth rates resulted in unexpectedly high productivities for being a microalga that naturally grows in acidic environments (0.32 g·L−1·d−1). The microalga also grows optimally on reduced carbon sources, including glucose and urea, and at an optimal temperature of 35°C. The alga pigment profile is particularly rich in carotenoids, especially lutein, suggesting that the microalga might have potential for antioxidant production, namely, xanthophylls.