In this study, extracellular lipases obtained from Acinetobacter psychrotolerans strains (Xg1 and Xg2) were characterized. The effects of varying pH values (3.0-10.0) and various temperatures (10-90 °C) on lipase activities were examined. Also the effects of different metal ions, organic solvents and detergents on lipases were studied. The extracellular crude lipases were concentrated using ultrafiltration. Zymogram analysis of these lipases was performed. Lipases exhibited maximum activity at pH 8 and 30 °C. While lipase obtained from the Xg1 strain exhibited the highest stability in the presence of various organic solvents, including hexane, ethyl acetate, chloroform and N,N dietil formamide, lipase obtained from the Xg2 strain was sensitive in the presence of isopropanol, acetonitrile, and butan-1-ol. The lipases of the Xg1 and Xg2 strains were inhibited in the presence of Cu2+ and Zn2+. Also, the lipase of the Xg1 strain was inhibited in the presence of Fe3+. In the presence of EDTA, the lipase activities of the Xg1 and Xg2 strains were partially inhibited. In presence of SDS, they were exactly inhibited. According to the zymogram results, the molecular weights of the lipases obtained from the Acinetobacter psychrotolerans Xg1 and Xg2 strains have been found approximately 37 and 30 kDa, respectively.
Acinetobacter, Lipase; Charecterization