Metagenomic analysis of soil microbiota under fluoride stress in the Purulia District, West Bengal, India

Fluoride is a mineral that exists widely in nature. Fluoride is a trace element necessary for normal development and growth of the body, but at concentrations above the threshold, it becomes highly toxic. The permissible limit for fluoride in drinking water set by the World Health Organization (WHO) and the Indian Bureau of Standards (BIS) is 1.5 mg ml-1. Fluoride toxicity is significantly higher in the western part of West Bengal, mainly in the three districts of Bankura, Purulia, and Birbhum, due to its geographical location compared to the eastern part. There is strong evidence that microbes are an alternative approach to fluoride scavenging due to bacterial cell wall compositions such as amines, sulfhydryl, carboxylates, and phosphates. These groups efficiently reduce fluoride and also help to adhere fluoride ions to the surface. Extensive research has yet to be conducted to decipher the microbiome structure of highly fluoride-contaminated soil. Detailed insight into the microbial communities that control the biogeochemical cycling of fluoride in natural soil systems is challenging due to their extreme diversity and untapped status. The impact of the problem as well as the dearth of information prompted this area of research to gain detailed insight into the microbial communities that control the biogeochemical cycling of fluoride in agricultural soils in the Purulia District, West Bengal, India.