Résumé
Selenium (Se) is a metalloid required at trace concentrations for normal metabolic activities of the cell. The bioavailable forms viz., selenate and selenite have been found in localized high concentrations in seleniferous environments. Studies are in progress on bacterial strains that were isolated from one such location in the North-West region of Punjab, India. A facultative anaerobe, identified as Pseudomonas aeruginosa by 16S rRNA gene homology, was isolated from the rhizosphere of crop plants from this region and was examined for selenium mobilization potential in the presence of selenium oxyanions. The isolate was observed to reduce 53 and 21% of sodium selenite and selenate to elemental selenium, respectively, and volatilize 4.7 and 5.1% within 72-hour duration. This is one of the few selenium tolerant aerobic bacteria isolated and reported from tropical seleniferous soils from India, and the first to show volatilization potential. These organisms are being considered for bioaugmenting Se-impacted soils for enhanced Se mobilization and removal.