Extraction and purification of lipase enzyme from Pseudomonas aeruginosa and study the antibacterial effect

Pseudomonas aeruginosa is an opportunistic pathogen capable of producing extracellular lipases with significant biotechnological and biomedical potential. This study aimed to isolate lipase-producing P. aeruginosa strains from clinical specimens, purify and characterize the extracellular lipase, and evaluate its antibacterial activity against selected pathogenic bacteria.A total of 120 clinical specimens collected from burn and wound infections were screened, and the isolate exhibiting the highest lipase production (P-5) was selected for enzyme production. The enzyme was purified through a multi-step protocol involving ammonium sulfate precipitation (75% saturation), dialysis, DEAE-cellulose ion-exchange chromatography, and Sephadex G-100 gel filtration chromatography. Lipase activity was determined using a titrimetric assay, while protein concentration was estimated by the Lowry method. The purified enzyme exhibited a final specific activity of 3.327 U/mg protein and an estimated molecular weight of approximately 29–32 kDa. Maximum enzyme activity was recorded at 35°C and pH 7.0, with residual activities of 91.14% and 85.57%, respectively. The purified lipase inhibited the growth of all tested bacteria, showing the lowest minimum inhibitory concentration (MIC) (125mg/mL) against Staphylococcus aureus and Streptococcus mutans, while higher MIC values were observed for Acinetobacter baumannii and Escherichia coli. These findings indicate that purified lipase from Pseudomonas aeruginosa possesses favorable biochemical properties and promising antibacterial activity, supporting its potential for future biotechnological and biomedical applications.