Vol. 2, Issue 8, Part E (2016)

Abstract
In India, according to WHO, fluoride content of drinking water in most of the cities is above the permitted level (1.5mg/L) and this high content of fluoride can lead to deformation of teeth and bones. Therefore, there is a need to reduce excessive fluoride from drinking water. The objective of this work was to study fluoride degradation by bacteria isolated from the ground water samples of 05 areas namely Nalgonda, Krishna, Karimnagar, Nacharam and Hitech City. Enrichment and isolation was carried out for all the samples in Brunner’s media, BHI and LB media. The optimal pH and temperature of the selected bacterial isolates were found to be 7.0 and 37 ⁰C respectively. Based on biochemical tests and morphological characters, selected bacterial strains were identified as Pseudomonas spp. Pseudomonas isolates showed fluoride tolerance of up to 100ppm. Isolation of plasmid DNA was carried out by Mini Prep method and it was run on agarose gel electrophoresis. The effect of bacterial isolates (showing presence of plasmid DNA) on fluoride content was checked by inoculating the bacteria in water samples and estimating the initial and residual fluoride content by colorimetric method. It was observed that the water sample treated with Pseudomonas has shown decreased levels of fluoride suggesting their ability to degrade and utilize fluoride for their growth. Presence of plasmid DNA suggests probable role in fluoride tolerance which can be further elaborated by plasmid curing, transformation etc. in future studies. Antibiotic sensitivity of the isolates was checked against different antibiotics from which they showed resistance to Ampicillin and Penicillin and sensitivity to Streptomycin. Thus such findings may be useful in designing a novel bacterial strain that can be used to return the altered environment to its original condition.