An investigation on heavy metal tolerance properties of bacteria isolated from textile effluent

The presence of high concentration of toxic heavy metals in industrial waste directly leads to contamination of receiving soil and water bodies and has deleterious impact on both human health and aquatic life. In the present study samples from textile mill effluent from different areas of Jessore city were analyzed for the identification and characterization of bacteria which shows tolerance to Copper, Mercury and Zinc. The bacterial isolates were characterized on the basis of their morphological and physiological studies including size and shape of the organisms, arrangement of the cells, presence or absence of spores, regular or irregular forms, gram reaction, cultural characteristics, IMViC test, H 2S production, nitrate reduction, deep glucose agar test etc. All the bacterial isolates belonged to 3 genera Bacillus, Enterobacter and Pseudomonas. All the gram positive isolates used in our study showed highest level of tolerance to Zn and moderate level of tolerance to Cu while gram negative isolates showed higher tolerance to Zn in comparison with Cu in nutrient broth. But all of the isolates showed almost no tolerance to Hg. So, our bacterial isolates have the probability to use in the treatment of industrial effluent containing heavy metals and thus pollution due to heavy metal can be controlled. The goal of this study was to identify heavy metal tolerant bacteria from the textile effluent. This kind of study is very significant for broader investigation to obtain data about metal tolerant bacteria considering their potential use for bioremediation and about the interactions between metals and bacteria.