Abstract:This manuscript describes the isolation of LX1 strain producing solvent-tolerant lipase from areas contaminated by crude oil and chemicals under the screening pressure of 10%(V/V)toluene.The isolate LX1 was identified as Pseudomonas aeruginosa by the analysis of 16S rDNA sequence.The optimal pH and temperature for lipase activity was 7.0 and 40 ℃,indicating the characteristic of neutral and medium temperature lipase.High stability of LX1 lipase was observed under a wide range of pH(6.5-10.5),and it was stable below 40 ℃.The chelating agent EDTA and metal ions such as Ba2+,Ca2+ had significantly activated the activity of LX1 lipase.This suggested that it could be a metal activated enzyme.LX1 lipase showed good tolerance in many kinds of 25%(V/V)hydrophilic and hydrophobic solvents.In the presence of n-Hexadecane,n-Tetradecane,n-Dodecane,n-Octanol,n-Heptitol and n-Hexanol,the half-life of LX1 lipase was markedly prolonged to 10 d;Additionally,in the presence of propylene glycol,DMF and DMSO,the half-life of LX1 lipase was prolonged to 5 d,which were higher than the half-life without organic solvents.These results indicated that LX1 lipase has potential application in organic solvents.
