%0 Journal Article
%T Immobilization of Penicillium citrinum Lipase on Ferromagnetic Azide-Dacron
%A M.C.B. Pimentel
%A A.B.F. Le£¿o
%A E.H.M. Melo
%A W.M. Ledingham
%J Biotechnology
%D 2006
%I Asian Network for Scientific Information
%X The immobilization of Penicillium citrinum lipase by covalent bond onto ferromagnetic azide-Dacron showed 73% of specific lipase activity retention with 7.3 mg protein/g support. There was no change in either optimal temperature (37¡ãC) or pH (8.0-8.5) after immobilization. The thermal stability of ferromagnetic azide-Dacron-Penicillium citrinum lipase derivative was significant, retaining 86.8% of lipolytic activity while the soluble enzyme retained only 34.2% after 1 h at 45¡ãC, this represented an improvement of 154% in the thermal stability. This lipase did not show inhibition by isopropanol. Both soluble and immobilized Penicillium citrinum lipases showed a kinetic of Michaellis-Menten to hydrolysis of 4-nitrophenyl palmitate of (4NPP) at 37¡ãC and pH 8.0. The values of KM were for soluble enzyme of 233 ¦ÌM and immobilized derivative of 276 ¦ÌM. This immobilized derivative showed a good operational stability keeping about 75% of initial activity after its reuse for 5 times. Also, it was stable to storage at 4¡ãC in Tris-HCl buffer pH 7.2 with a half-life of 25 days. Immobilized Penicillium citrinum lipase was able to catalyse the synthesis of triolein using glycerol and olive oil as substrates free of organic solvent, with 80% of conversion after 20 h at 40¡ãC.
%K Lipases
%K Penicillium citrinum
%K Ferromagnetic azide-Dacron
%K triacylglycerol acyl-hydrolases
%U http://docsdrive.com/pdfs/ansinet/biotech/2006/228-233.pdf