ISSN 00262617, Microbiology, 2011, Vol. 80, No. 4, pp. 483–487. © Pleiades Publishing, Ltd., 2011. 483 Lipases (triacylglycerol acylhydrolases, EC 3.1.1.3) display the capability to catalyze the hydrolysis of trig lycerides to diacylglycerides, monoglycerides and fatty acids, under aqueous conditions [1, 2]. They also have esterolytic activity on distinct substrates. Due to their multifaceted attributes, they are gaining importance for biotechnology. These enzymes are ubiquitous in nature and are widely distributed in plants, animals, and microorganisms such as bacteria, yeasts, and fungi [3–5]. Microbial lipases have immense applications in various fields, such as food, pharmaceutical, cosmetic, agrochemical, feedstock, detergent, textile, biodiesel and oil processing industries, in synthesis of fine chemicals and new polymeric materials, as well as in waste water treatment [1, 4, 6, 7]. Besides, recently the process of lipid modification using lipases has attracted significant attention. Different types of reac tions they can catalyze in the absence of cofactors, a high stability in organic solvents and the ability to cat alyze specific reactions with chemo, regio, and enantioselectivity, make them potentially the enzymes for biotechnological process [7, 8]. Most industrial enzymatic conversions may be inhibited by concentrated salt solutions and high tem peratures; thus, microbial enzymes that display opti mal activity at a wide range of temperature, pH and ionic strength, would be considered as useful biocata lysts in industrial process [6, 10, 11]. Moderately halophilic bacteria which can grow optimally in media containing 3–15% NaCl, are a valuable source of such enzymes. Therefore, screening and isolation of moderate and extreme halophiles from hypersaline environments, able to produce these enzymes would be useful for further industrial applica tions [6, 11]. It has been shown that the most efficient lipase producing bacteria belong to various species of Bacil lus genera, such as Bacillus cereus C71, B. thermoleo vorans ID1, B. coagulans BTS3, Geobacillus sp. TW1 [4], Bacillus sp. strain L2, B. sphaericus 205y, B. bogoriensis sp. nov., B. salarius sp. nov. and B. sphaericus JS1 and other Bacillus species [1 ⎯5, 12 ⎯19]. Bacillus species are taxonomically very diverse and have been isolated from different saline habitats such as salterns, estuarine water, salt lakes, salty foods, sea ice and deepsea hydrothermal vents [18]. The aim of this study is to isolate and identify some lipaseproducing halophilic bacteria from the Maha rla, a hypersaline lake in south of Iran, using 16S rRNA as a molecular marker. Their lipase activities were also determined. Isolation and Characterization of Some Moderately Halophilic Bacteria with Lipase Activity 1 Y. Ghasemi a, b , S. RasoulAmini a, b , A. Kazemi a , G. Zarrini c , M. H. Morowvat a, b , and M. Kargar a a Pharmaceutical Sciences Research Center, Shiraz University of Medical Sciences, P.O. Box 71365158, Shiraz, Iran b Department of Pharmaceutical Biotechnology, School of Pharmacy Shiraz University of Medical Sciences, P.O. Box 713451583, Shiraz, Iran c Department of Animal Biology, Faculty of Natural Sciences, University of Tabriz, Tabriz, Iran Received October 29, 2010 Abstract—Lipases are an important class of enzymes which catalyze the hydrolysis of long chain triglycerides and constitute the most prominent group of biocatalysts for biotechnological applications. There are a num ber of lipases, produced by some halophilic microorganisms. In this study, some lipase producing bacteria from the Maharla salt lake located in south of Iran were isolated. All isolates were screened for true lipase activity on plates containing olive oil. The lipase activity was measured using titrimetric methods. Among thirty three isolates, thirteen strains demonstrating orange zone around colonies under UV light, were selected for identification using the molecular methods and some morphological characteristics. The bacte rium Bacillus vallismortis BCCS 007 with 3.41 ± 0.14 U/mL lipase activity was selected as the highest lipase producing isolate. This is the first report of isolation and molecular identification of lipase producing bacteria from the Maharla lake. Keywords: lipase, Bacillus vallismortis, halophilic bacteria,the Maharla Salt Lake. DOI: 10.1134/S0026261711040060 1 The article is published in the original. 2 Corresponding author; email: rasoulamin@sums.ac.ir EXPERIMENTAL ARTICLES