Purification and characterization of organic solvent-stable lipase from organic solvent-tolerant Pseudomonas aeruginosa LST-03

An organic solvent-stable lipase (LST-03 lipase) secreted into the culture broth of the organic solvent-tolerant Pseudomonas aeruginosa LST-03 was pur ified by ion-exchange and hydrophobic interaction chromatography in the pre sence of 2-propanol. The purified enzyme was homogeneous as determined by S DS-PAGE. The molecular mass of the lipase was estimated to be 27.1 kDa by S DS-PAGE and 36 kDa by gel filtration. The optimum pH and temperature were 6 .0 and 37 degrees C. LST-03 lipase was stable at pH 5-8 and below 40 degree s C. Its hydrolytic activity was highest against tricaproin (C6), methyl oc tanoate (C8), and coconut oil respectively among the triacylglycerols, fatt y acid methyl esters, and natural oils investigated. The enzyme cleaved not only the 1,3-positioned ester bonds, but also the 2-positioned ester bond of triolein. It exhibited high levels of activity in the presence of n-deca ne, n-octane, DMSO, and DMF as well as in the absence of an organic solvent , in addition, LST-03 lipase was stabler in the presence of n-decane, ethyl eneglycol, DMSO, n-octane, n-heptane, isooctane, and cyclohexane than In th e absence of an organic solvent.