초록
Lipase from the newly isolated Pseudomonas aeruginosa strain was produced, and its activity was enhanced through response surface methodology optimization. In the initial screening process, the bacterial strain was isolated from soil samples and then confirmed with lipase production on agar plates supplemented with Rhodamine B. The strain was identified by 16S rRNA gene sequence analysis. Plackett-Burman design was used to initially screen nine factors of culture medium. The design showed that four factors including peanut oil, sucrose, ammonium sulfate and volume of the medium exhibited significant affect on lipase production by P. aeruginosa strain. Afterward the optimal level of each significant factor was derived by Box-Behnken design and a 13.7 fold increase in lipase activity (21 U/mL-288 U/mL) was achieved under the optimum conditions. Thirty six percent of the soybean oil was converted into free fatty acids after hydrolyzing the oil for 12 h in the presence of optimized lipase.