Plant Growth Promoting and Metal Bioadsorption Activity of Metal Tolerant Pseudomonas aeruginosa Isolate Characterized from Uranium Ore Deposit

In the present study, a metal-tolerant fluorescent pseudomonad isolated from uranium ore rich deposit of Domiasiat in North-East India was identified as Pseudomonas aeruginosa DPs-13 based on morphological, biochemical and molecular analysis. The isolate showed higher tolerance to uranium and other metals like copper, cadmium, zinc and lead when compared with the reference strain P. aeruginosa MTCC2474. When checked for uranyl bioadsorption potential, the isolate showed 94 % (22.5 mg/L) and 72 % (342.7 mg/L) removal of uranium (VI) when challenged with 100 μM (23.8 mg/L) and 2 mM (476 mg/L) uranyl nitrate solutions within 1 h of incubation as compared to 68 % (16.18 mg/L) and 25 % (119 mg/L) when challenged with above concentrations respectively of uranyl nitrate by the reference strain. The isolate was resistant to most of the commonly used antibiotics like Ampicillin, Kanamycin, Chloramphenicol, Erythromycin, Aztreonam, Tetracycline, Ciprofloxin and Streptomycin. The isolate had no phytotoxic effect, produced siderophores, possessed phosphate solubilising ability as well as two antibiotic producing genes, and had antagonistic activity against plant pathogens. Plasmid occurrence was also noticed in the isolate. The isolate from the uranium ore rich site besides being a promising metal tolerant bacterium had potent plant growth promoting activity and can be used to promote plant growth in bioremediation approaches in metal contaminated sites.