Abstract

A bacterium, Pseudomonas lubricans, isolated from heavy metal laden industrial wastewater, has been shown to tolerate multiple heavy metals suggesting its importance in bioremediation of industrial effluents. P. lubricans tolerated As(III) up to 3 mg ml^-1, Cu²⁺ up to 0.7 mg ml^-1, Hg²⁺ up to 0.4 mg ml^-1, Ni²⁺ up to 0.4 mg ml^-1 and Cr⁶⁺ up to 0.5 mg ml^-1. P. lubricans showed optimum growth at pH 7 while optimum temperature for growth was 30°C. P. lubricans could oxidize As(III) 42% (42 µg mg^-1 of protein), 78% (78 µg mg^-1 of protein) and 95% (95 µg mg^-1 of protein) from the medium after 24, 48 and 72 h of incubation at optimal conditions, respectively. The arsenite oxidizing ability shown by P. lubricans indicates its potential application in biological treatment of wastewaters contaminated with arsenic.

Key words: Arsenic, wastewater, Pseudomonas lubricans, bioremediation.