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 ?g/ml. Pseudomonas sp. AN29 could tolerate Pb2+ (600 ?g/ml), Cu2+ (200 ?g/ml), Cd2+ (50 ?g/ml), Zn2+ (50 ?g/ml), Ni2+ (550 ?g/ml) and Cr6+ (150 ?g/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?C and at pH of 8. Metal processing ability of the isolate was determined in a medium containing 100 ?g/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 37oC. 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.