Purification and partial characterization of two new cold-adapted lipases from mesophilic Geotrichum sp SYBC WU-3

Two cold-adapted lipases (Lipase-A and Lipase-B in the paper) of mesophilic Geotrichum sp. SYBC WU-3 were purified by using (NH4)(2)SO4 fractionation, chromatography separation on a DEAE-cellulose-32 column and a Sephadex G100 column. The molecular mass of Lipase-A and Lipase-B were determined to be approximately 41.1 and 35.8 kDa, respectively by SDS-PAGE. The optimum temperature for the activity of Lipase-A was found to be 20 degrees C, and that of Lipase-B was 15 degrees C. Lipase-A and Lipase-B had good stability when temperature was below 40 degrees C. Both the optimum pH for the activity of the lipases was 9.5. Lipase-A retained about 80% of its activity when pH was between 3 and 6 and Lipase-B maintained over 80% activity in the pH range of 3-8. The two lipases showed hydrolysis efficiency to various p-nitrophenyl esters, but they were more active with shorter p-nitrophenyl esters (C2 and C4). (C) 2009 Elsevier Ltd. All rights reserved.