Isolation and characterization of phosphate solubilizing bacterium Pseudomonas aeruginosa KUPSB12 with antibacterial potential from river Ganga, India

In the present study, the antibacterial potential of a phosphate solubilizing bacterium isolated from the river Ganga, West Bengal, India was investigated. Experimental studies found that the strain KUPSB12 was effective in phosphate solubilization with phosphate solubilization index of 2.85 in Pikovskaya's agar plates along with very high soluble phosphate production of 219.64 ± 0.330 μg mL−1 in liquid medium. The phosphate solubilizing bacterium was identified using physiological, morphological and biochemical characters as well as 16S rRNA gene sequencing. The phosphate solubilizing bacterium was identified as a strain of Pseudomonas aeruginosa. The antibacterial activity of the cell-free filtrates of this isolate was evaluated against three Gram negative bacteria (Escherichia coli MTCC 443, Shigella flexneri MTCC 1457 and Vibrio cholerae MTCC 3904) and three Gram positive bacteria (Bacillus subtilis MTCC 441, Micrococcus luteus MTCC 1538 and Staphylococcus aureus MTCC 3160). P. aeruginosa KUPSB12 strain showed the wide inhibitory spectrum against all tested pathogenic bacterial stains. Among the bacteria tested M. luteus MTCC 1538 was found to be most susceptible (19.33 ± 0.33 mm) to the cell-free filtrates of this isolate. These findings suggest that the identified strain may be utilized for screening the antibacterial substances to formulate new treatments for infections caused by pathogenic bacteria.