Comparison of physicochemical properties of lipase in Pseudomonas aeruginosa isolated from wound and oil contaminated soil.

BACKGROUND AND ABJECTIVEPseudomonas aeruginosa is a Gram-negative and opportunistic bacterium. Large number of pathogenic factors and high antibiotic resistance make it very difficult to eradicate this bacterium from lung infections of cystic fibrosis patients. This bacterium is widely used in industry and has a number of active extracellular enzymes. In this research, a comparison has been made between Pseudomonas lipase isolated from a patient's wound and oil-contaminated soil.MATERIALS AND METHODSFirst, two strains were cultured in a salt-based medium with olive oil as a carbon source. After ۷۲ hours, the medium was centrifuged and the supernatant was used as a source of lipase. The enzyme activity was compared at different pH, temperature and ionic strength.RESULTS AND DISCUSSIONThe results showed that in the wound strain, the highest and lowest activity was seen at pH ۹ and۴, respectively, while in the soil strain, the highest and lowest activity was seen at pH ۸ and۶. The study of the effect of temperature on lipase activity showed that in the wound strain, the highest and lowest activity was observed at ۶۰ and ۷۰ °C, respectively, while in the soil strain, the highest activity was observed at۳۰°C and the lowest at ۶۰°C. The effect of changing the ionic strength (different NaCl concentration) on lipase showed that in the wound strain, the highest and lowest activity was observed in ۰.۳ and ۱ M NaCl, respectively, while in the soil strain, the highest activity was observed in ۰.۵ M and the lowest in۱ M NaCl.CONCLUSIONThe comparison of the above results shows that the physicochemical behaviours of the lipase enzyme from the wound and soil strains is completely different from each other, and it can be suggested that the structure of the secreted lipase from the wound strain is different from the structure of the enzyme from the soil strain

کلیدواژه ها:

Lipase ، wound ، soil ، bacteria