Fluoride-Resistant Priestia aryabhattai isolated from Silkworm Feces: A Promising Agent for Fluoride Bioremediation

Abstract

Priestia aryabhattai SF-F, a bacterium isolated from the fecal matter of silkworms, demonstrates significant resistance to fluoride, sustaining growth in sodium fluoride (NaF) concentrations as high as 45 mg/L. Its fluoride removal efficiency was assessed using a Fluoride Ion Selective Electrode, which confirmed a substantial capacity for fluoride degradation, suggesting its potential for application in bioremediation of fluoride contaminated environments. Biochemical characterization identified P. aryabhattai SF-F as a Gram-positive, motile organism exhibiting positive responses to methyl red and catalase activity tests. Antibiotic susceptibility profiling based on minimum inhibitory concentration (MIC) assays revealed the greatest sensitivity to streptomycin (6 µg), followed by ampicillin (8 µg), while higher MIC values for chloramphenicol and tetracycline (20 µg each) indicated comparatively reduced susceptibility. Morphological analysis using Scanning Electron Microscopy (SEM) indicated cellular alterations under fluoride stress, while Energy Dispersive X-ray (EDX) spectroscopy confirmed the presence of fluoride within the bacterial cells, suggesting intracellular accumulation. Collectively, these findings establish P. aryabhattai SF-F as a strong candidate for microbial based fluoride remediation strategies, offering an eco-friendly approach to mitigating fluoride pollution in affected environments.