Characterization of lipases isolated from Acinetobacter psychrotolerans strains

In this study, lipolytic activities of Acinetobacter psychrotolerans Xg1 and Xg2 strains were qualitatively determined in Tween 20, Tween 80 and Tributirin Agar. For lipase activite test was used Rhodamine B agar medium. Both strains gave positive results in this medium. Lipase activities using p-nitrophenyl palmitate was quantitatively measured by a spectrophotometer. The highest lipase activities of Xg1 and Xg2 strains were 0,14 and 0,13 U, respectively. Time course of enzyme activity by Xg1 was found in the 24th hour, but Xg2 was found in the 48th hour. Next, extracellular lipases of Acinetobacter psychrotolerans Xg1 and Xg2 strains were characterized. Both enzymes exhibited maximum activity at pH 8 and 30 oC. The enzyme exhibited the highest stability in the presence of various organic solvents such as hexane, ethyl acetate, chloroform and N,N dietil formamid, but it was determined reducing at organic solvents isopropanol, asetonitril and bütan-1-ol. The lipase of Xg1 strain was inhibited in the presence FeCl3, CuCl2 ve ZnCl2, but the lipase of Xg2 strain was inhibited in the presence CuCl2 ve ZnCl2. When in presence EDTA, the lipase activities of Xg1 and Xg2 strains was inhibited. İn presence SDS, they was exactly inhibited. In culture supernatants obtained from Xg1 and Xg2 strains were performed ultrafiltration, gel filtration chromatography, SDS-PAGE and activite tests, respectiviely.