Tehran University of Medical Sciences Iranian Journal of Microbiology 2008-3289 3 2 2011 06 15 92 98 EN E Mobarak-Qamsari Department of Biology, Alzahra University, Vanak, Tehran, Iran. R Kasra-Kermanshahi Department of Biology, Faculty of Sciences, Alzahra University, Vanak, Tehran, Iran. Z Moosavi-nejad Department of Biology, Faculty of Sciences, Alzahra University, Vanak, Tehran, Iran. 2015 10 01 Background and Objectives: Lipases are particularly important due to the fact that they specifically hydrolyze acyl glycerol, oils and greases, which is of great interest for different industrial applications. Materialst and Methods: In this study, several lipase-producing bacteria were isolated from wastewater of an oil processing plant. The strain possessing the highest lipase activity was identified both biochemically and sequencing of 16S rRNA gene. Then we increase lipase activity by improving conditions of production medium. Also, lipase from this strain was preliminarily characterized for use in industrial application. Results: The 16S rRNA sequensing revealed it as a new strain of Pseudomonas aeruginosa and the type strain was KM110. An overall 3-fold enhanced lipase production (0.76 U mL-1) was achieved after improving conditions of production medium. The olive oil and peptone was found to be the most suitable substrate for maximum enzyme production. Also the enzyme exhibited maximum lipolytic activity at 45°C where it was also stably maintained. At pH 8.0, the lipase had the highest stability but no activity. It was active over a pH range of 7.0-10.0. The lipase activity was inhibited by Zn2+ & Cu2+ (32 and 27%, respectively) at 1mM. The enzyme lost 29% of its initial activity in 1.0% SDS concentration, whereas, Triton X-100, Tween-80 & DMSO did not significantly inhibit lipase activity. Conclusions: Based on the findings of present study, lipase of P. aeruginosa KM110 is a potential alkaline lipase and a candidate for industrial applications such as detergent, leather and fine chemical industries. https://ijm.tums.ac.ir/index.php/ijm/article/view/94 https://ijm.tums.ac.ir/index.php/ijm/article/download/94/93