Isolation, characterization and identification of fluoride tolerant bacterium Escherichia sps. strain FRB-1

Abstract

The toxic impacts of high doses of fluoride have been witnessed on microbial community in form of reduction of number and diversity, which in-turn influence the soil fertility. Such ecological systems generally harbor microbes with varying mechanisms of fluoride tolerance. The present study focuses on the isolation, characterization and identification of fluoride tolerant bacterial isolate FRB1 isolated from soil of Bharatpur district, Rajasthan, India. The soil was characterized for fluoride content and other physicochemical characteristics as pH, electrical conductivity, organic carbon and organic matter, chloride, water holding capacity and available phosphorus. The growth reduction study on FRB 1 with increasing fluoride stress was used to determine the minimum inhibitory concentration (3000ppm). The stain FRB-1 as identified by 16SrDNA sequencing followed by alignment of the amplified sequence with nrdatabase of Genbank through BLASTn analysis showed 97% homology with Escherichia sps. The bacterium was further characterized for staining and biochemical characteristics. The high fluoride stress tolerance assures its survival as well as preponderance in stressed soil systems indicating their possible application in natural or artificial remediation of toxicant exposed degraded soil systems.