Screening of cadmium resistant isolates and evaluation of the bacterial diversity

Cadmium is a non-essential heavy metal. It is well known for its toxicity, bioaccumulation and biomagnifications. It has a wide range of sources and exists in environment as well and industry in various forms. Microbes have been utilized as a bioremediation vehicle with use of genetic engineering approaches. A diverse group of microbes play an important role in this direction. In this study, six cadmium resistant isolates (710A, 710B, KNP3, KNP9, 97AN & 62BN) were used for diversity analysis. Diversification characterization was accomplished with combination of Restriction Fragment Length Polymorphism (RFLP) and Tm (melting temperature). Phylogenetic analysis after restriction digestion indicated that the six isolates viz. 710A, 710B, 62BN, 97AN, KNP3, KNP9 were grouped into three clusters at a similarity coefficient of 48%. Three isolates namely KNP3, 62BN and 710A were grouped into one cluster; KNP9 and 710B were present into second cluster while isolate 97AN was distinct and entirely separated from all other five isolates. Isolate 710A (Pseudomonas putida) and 710B (Commamonas aquatica) both exhibited highest diversification and distinct parental lineage. This study will be helpful to extract the heavy metals from the rhizosphere which will finally be useful for improving the conditions of soil for plant growth.