Isolation and characterization of zinc resistant bacteria from zinc contaminated sites

Abstract

Heavy metals such as zinc are toxic to a variety of organisms and pose various environmental threats. Conventional methods to detoxify zinc are often costly and have high energy requirements. Microorganisms however have developed various mechanisms that lead to resistance against zinc. Actinomycetes are known to be present in stressful conditions and hence resist the effect of toxicity of zinc. Various biochemical test confirmed the isolated species ZRB 7 to be streptomyces species, which have been earlier reported in various articles to exhibit the property of resistance against heavy metals. The species showed maximum tolerance to 25 mM of zinc on solid media and 28 mM on liquid media. Moreover it showed coresistance to lead which is another toxic heavy metal and could grow in the higher presence of lead than zinc on solid media and hence the identified streptomyces species is a good future prospect for bioremediation of heavy metal contamination in soil.