Uptake of mercury by a bacterium, Pseudomonas sp. AN29, isolated from industrial effluents and its potential use in wastewater treatment

Document Type: Regular Paper

Authors

Department of Microbiology and Molecular Genetics, University of the Punjab, New Campus, Lahore 54590, Pakistan

Abstract

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 Hg
 
2+ was 500 μg/ml. Pseudomonas
 
sp. AN29 could tolerate Pb
 
2+ (600 g/ml), Cu2+ (200 g/ml), Cd2+ (50 g/ml), Zn2+ (50 g/ml), Ni2+ (550 g/ml)
and Cr
 
6+ (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 37ºC and at pH of 8. Metal processing ability of the
isolate was determined in a medium containing 100 μg/ml of Hg
 
2+. Pseudomonas sp. AN29 could decrease 85%
of mercury from the culture medium after 40 hours and was also able to remove Hg
 
2+ 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 Hg
 
2+ (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.

Keywords