Heavy Metal Uptake by Euplotes mutabilis and its Possible Use in Bioremediation of Industrial Wastewater

A ciliate protozoan, Euplotes mutabilis, isolated from heavy metal laden industrial wastewater, has been shown to tolerate multiple heavy metals thus suggesting its significance in bioremediation of industrial effluents. This ciliate tolerated Zn²⁺ up to 33 μg/mL, Cd²⁺ up to 22 μg/mL and Ni²⁺ up to 18 μg/mL. The ciliate could uptake 85% Zn²⁺, 84% of Cd²⁺ and 87% of Ni²⁺ after 96 h of inoculation of growth medium containing 10 μg/mL of Zn²⁺ and 5 μg/mL of Cd²⁺ and Ni²⁺, with actively growing ciliates. After 6 days of incubation the ciliate removed 87% Cd²⁺, 92% Ni²⁺, and 93% Zn²⁺ from the wastewater. The heavy metal uptake capability of Euplotes mutabilis may be employed for metal detoxification operations.