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Abstract:
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The production of heavy metals has increased quickly since the industrial
revolution. Heavy metals frequently form compounds that can be toxic, carcinogenic,
or mutagenic, even in very small concentrations. The usual techniques
of removing metals from wastewaters are in general expensive and
have many restrictions. Alternative methods of metal removal and recovery
based on biological materials have been measured. Among various agents,
the use of microbes for the removal of metals from industrial and municipal
wastewater has been proposed as a promising alternative to conventional
heavy metal management strategies in past decades. Thus, the present study
aims to isolate and characterize bacteria from soil, sediment, and waters of
metal-contaminated industrial area to study the zinc resistance patterns and
the zinc bioaccumulation potential of the selected microorganism. Zinc analysis
of the samples revealed that concentrations varying from 39.832 m g/L to
310.24 m g/L in water, 12.81 m g/g to 407.53 m g/g in soil, and 81.06 m g/g to
829.54 m g/g in sediment are present. Bacterial zinc resistance study showed
that tolerance to Zn was relatively low (<500 m g/ml). Ten bacterial genera
were represented in soil and 11 from water, while only 5 bacterial genera
were recorded from sediment samples. Bacillus, Pseudomonas , and
Enterobacter were found in soil, sediment, and water samples. Highly zincresistant
Bacillus sp. was selected for zinc removal experiment. Zinc removal
studies revealed that at pH 5 about 40% reduction occurs; at pH 7, 25%
occurs; and at pH 9, 50% occurs. Relatively an increased removal of Zinc
was observed in the fi rst day of the experiment by Bacillus sp. The metal
bioaccumulative potential of the selected isolates may have possible applications
in the removal and recovery of zinc from industrial ef fluents. |