Characterization of fluoride-tolerant halophilic Bacillus flexus NM25 (HQ875778) isolated from fluoride-affected soil in Birbhum District, West Bengal, India

• Published in: Environmental monitoring and assessment Vol. 186; no. 2; pp. 699 - 709
• Main Authors: Pal, Kartick Chandra, Mondal, Naba Kumar, Chatterjee, Soumendranath, Ghosh, Tuhin Subhra, Datta, Jayanta Kumar
• Format: Journal Article
• Language: English
• Published: Dordrecht Springer-Verlag 01.02.2014; Springer Netherlands; Springer Nature B.V
• Subjects: Adaptation, Physiological; agar; ampicillin; Analysis; Atmospheric Protection/Air Quality Control/Air Pollution; Bacillus; Bacillus - classification; Bacillus - isolation & purification; Bacillus - physiology; Bacillus flexus; Bacteria; Bioaccumulation; Biodegradation, Environmental; Catalase - metabolism; doxycycline; Earth and Environmental Science; Ecology; Ecotoxicology; Environment; Environmental Management; Environmental Monitoring; Enzymes; Fluorides; Fluorides - analysis; Fluorides - metabolism; gentamicin; Hydrogen sulfide; India; kanamycin; Microorganisms; Minerals; Monitoring/Environmental Analysis; nalidixic acid; Nitrate reduction; nucleotide sequences; ofloxacin; Organisms; Oxidoreductases - metabolism; phylogeny; proteinases; ribosomal DNA; ribosomal RNA; rifampicin; Sodium chloride; Soil - chemistry; Soil contaminants; Soil Microbiology; Soil Pollutants - analysis; Soil Pollutants - metabolism; Soil quality; streptomycin; Studies; triacylglycerol lipase; urease; vancomycin; India; India, West Bengal; Fluoride tolerance; Birbhum; Fluoride-contaminated soil
• ISSN: 0167-6369; 1573-2959
• DOI: 10.1007/s10661-013-3408-8

A new Gram-positive, nonpigmented, rod-shaped fluoride-tolerant bacterial strain, NM25, was isolated from waterlogged muddy field soil collected from the fluoride endemic area of Rampurhat II block (average fluoride in water, 4.7 mg/l, and in soil, 1.5 mg/kg) in Birbhum District, West Bengal, India. The study was undertaken to characterize the fluoride-tolerant bacterial isolate, to determine its role in bioaccumulation of fluoride, and to analyze the water and soil quality of the bacterial environment. The isolate was positive for catalase, lipase, urease, protease, oxidase, and H₂S production, but negative for indole production, nitrate reduction, and Vogues–Proskauer test. The organisms were sensitive to recommended doses of ofloxacin, kanamycin, rifampicin, levofloxacin, vancomycin, gatifloxacin, gentamicin, doxycycline, streptomycin, and nalidixic acid but resistant to ampicillin. Based on the phenotypic characteristics, 16S rRNA gene sequence, and phylogenetic analysis, the bacterial isolate NM25 was identified as Bacillus flexus. The G+C content of the 16S rDNA was 53.14 mol%. This strain tolerated up to 20 % (w/v) NaCl in nutrient agar medium and was grown at the pH range 4–12. It reduced fluoride concentration up to 67.45 % and tolerated more than 1,500 ppm of fluoride in brain–heart infusion agar medium.