Heavy metal resistant Distigma proteus (Euglenophyta) isolated from industrial effluents and its possible role in bioremediation of contaminated wastewaters

• Published in: World journal of microbiology & biotechnology 2007-06, Vol.23 (6), p.753-758
• Main Authors: Rehman, A, Shakoori, Farah R, Shakoori, A. R
• Format: Article
• Language: English
• Subjects: Algae; Algal culture; Biological and medical sciences; Bioremediation; Biotechnology; Cadmium; Cell culture; Chromium; Cleanup operations; Copper; Detoxification; Distigma; Distigma proteus; Effluents; Environmental cleanup; Fundamental and applied biological sciences. Psychology; Heavy metals; Industrial effluents; Industrial wastes; Industrial wastewater; Lead; Metal ions; metal tolerance; Metals; Reduction (metal working); Studies; Wastewater; Wastewater pollution
• ISSN: 0959-3993; 1573-0972
• DOI: 10.1007/s11274-006-9291-5

The alga, Distigma proteus, isolated from industrial wastewater showed tolerance against Cd²⁺ (8.0 μg/ml), Cr⁶⁺ (12 μg/ml), Pb²⁺ (15 μg/ml) and Cu²⁺ (10 μg/ml). The metal ions slowed down the growth of the organism after 4-5 days of exposure. The reduction in cell population was 90% for Cu²⁺, 84% for Cd²⁺, 71% for Cr⁶⁺, and 63% for Pb²⁺ after 8 days of metal stress. The order of resistance to heavy metal, in terms of reduction in the cellular population, was Cu²⁺ > Cd²⁺ > Cr⁶⁺ > Pb²⁺. Chromium- and cadmium-processing capabilities of the alga were worked out for its potential use as a bioremediator of wastewater. The reduction in the amount of Cr⁶⁺ after 2, 4, 6 and 8 days of algal culture containing 5.0 μg Cr⁶⁺ ml-¹ of culture medium was 77, 85, 92 and 97%, respectively. Distigma could also remove 48% Cd²⁺after 2 days, 68% after 4 days, 80% after 6 days and 90% after 8 days from the medium. The heavy metal uptake ability of Distigma can be exploited for metal detoxification and environmental clean-up operations.