Ponniah Anusha
Periyar University, India
Title: Heavy metal resistant bacteria Bacillus thuringiensis isolated from Bauxite mine soil, Kolli hills, Eastern Ghats, Tamilnadu, India
Biography
Biography: Ponniah Anusha
Abstract
Heavy metal pollution spreading to the environment due to human activities such as mining, smelting, e-waste dumping etc. Kolli hills are part of the Eastern Ghats of Tamilnadu harbour rich in biodiversity. Mining activities in study area being created heavy metal contamination in surrounding areas which can affect the microbial, flora and fauna biodiversity and soil fertility. Remediation of heavy metal contaminated sites necessary to turn the beneficial. The indigenous bacteria are evolving as resistant to the heavy metal to some extent such microbes can be used for the metal removal and metal recovery from the polluted sites. This study was aimed to screen the metal resistant bacteria from the heavy metal contaminated soil samples. The efficient two bacterial isolates (A1-2 and A1-3) were isolated and identified as Bacillus spp., through conventional staining and biochemical tests. The bacterial strains were further confirmed by 16S rRNA sequencing and phylogenetic tree which reveals that, the isolates 100 % similarity with the Bacillus thuringiensis and the sequences were submitted to the GenBank. The multi metal resistant of isolates was assessed through the minimum inhibitory concentration (MIC) method. The bacterial strains were studied for tolerance to heavy metals such as Copper, Chromium, Lead and Zinc in different concentrations ranging from 10, 20, 40 to 640µg/ml. At the concentration of 10µg/ml, B.thuringiensis A1-2 showed resistant of about 98.94 %, 77.91 %, 76.23 % and 60.41 %, whereas, B.thuringiensis A1-3 found 99.66 %, 87.68 % and 98.87 % resistant to Cu, Cr, Pb and Zn respectively. At the concentration of lead (640µg/ml), the isolates A1-2 and A1-3 showed resistant effect of about 44.5 % and 33.39 % and the outcome of this study found that the strains are having the viability to withstand in high lead stress condition. These results confirmed that the both strains were highly tolerant to lead when compared with Cu, Cr and Zn. Further, the antibiotic profiles of these two bacterial strains were investigated by disc diffusion method and show sensitive to tested antibiotics. Thus, the present study suggested that the bacterial isolates explore potential adaptation to the selected heavy metals which can be applicable for the alternative remediation agent to reduce the heavy metals contamination in the hilly environment. This work was funded by Science and Engineering Research Board (SERB), New Delhi, India (SB/YS/LS-25/2013) under Start up grant for young scientists.