UPTAKE OF MERCURY BY A BACTERIUM, PSEUDOMONAS SP. AN29, ISOLATED FROM INDUSTRIAL EFFLUENTS AND ITS POTENTIAL USE IN WASTEWATER TREATMENT

The present study is aimed at assessing the ability of Pseudomonas sp. AN29 to uptake Hg²⁺ from the metal contaminated environment. The minimum inhibitory concentration (MICs) of Hg²⁺ was 500 mg/ml. Pseudomonas sp. AN29 could tolerate Pb²⁺ (600 mg/ml), Cu²⁺ (200 mg/ml), Cd²⁺ (50 mg/ml), Zn²⁺ (50 mg/ml), Ni²⁺ (550 mg/ml) and Cr⁶⁺ (150 mg/ml). The isolate showed typical growth curve but phases (lag and log) extended in the presence of mercury. Bacterial isolate showed optimum growth at 37^oC and at pH of 8. Metal processing ability of the isolate was determined in a medium containing 100 mg/ml of Hg²⁺. Pseudomonas sp. AN29 could decrease 85% of mercury from the culture medium after 40 hours and was also able to remove Hg²⁺ 10%, 40%, 50% and 56% from the growth medium after 8, 16, 24 and 32 hours, respectively. Pseudomonas sp. AN29 was also able to uptake 74% of Hg²⁺ (pellet) from the medium after 24 hours of incubation at 37^oC. Excellent metal uptake ability of Pseudomonas sp. AN29 indicates the possibility of using the bacterial strain for the removal of mercury from metal-contaminated wastewater.