Biochemical Characterization of Lipase Produced by Bacillus spp. Isolated from Soil and Oil Effluent

The aim of the present work was to isolate Bacillus spp. With high lipase activity; to characterize the isolates using both biochemical and molecular methods; to produce lipase using Bacillus isolates and to study the biochemical and biophysical characteristics of the produced lipase. Sixty five Bacillus isolates were isolated from soil 20 isolates from guar field soil (G), 15 isolates from Abusabein field soil (B), 15 isolates from sun flower field soil (S) and 15 isolates from oil effluent (O). Lipase producing isolates were screened; a Chromogenic plate’s method was used. Enzyme activity was quantitatively assayed. Lipase production under submerged fermentation (SMF) conditions using a production medium that contained metal salts, Tween-20 and olive oil as substrate at different period 24, 48, 72 and 96 h, the optimum pH, temperature for lipase activity was determinated and kinetics as well. The isolates showed the highest lipase activity which was identified as Bacillus sp. The optimum pH, temperature, thermostability and kinetic of the produced enzymes were found in three isolates G14, O1 and B10 with the highest enzyme activity and best stability. The isolates G14, O1 and B10 revealed the highest lipase activity of 63.4, 41.2 and 28.3 U/ml, respectively. The results showed optimum pH of the lipase activity from isolates G14, O1 and B10 8.0, 6.0 and 6.0 and the optimum temperature 40, 60 and 75˚C, respectively. Lipase enzymes from isolates O1 and B10 were found to be more thermostable after incubation time for 120 min at 90˚C. The Vmax and Km values of lipase for isolates G14, OI and B10 were 17.6, 135 and 24.4 μmole∙min𕒵 and 1.3, 1.6 and 0.681 mM, respectively. According to these results Bacillus spp. with high lipase activity and thermostability can be used to promote food, pharmaceuticals, paper, detergents agrochemicals industries and pollution control in Sudan.