%0 Journal Article
%T Purification and Characterization of a Thermostable Lipase from Geobacillus thermodenitrificans IBRL-nra
%A Anuradha Balan
%A Darah Ibrahim
%A Rashidah Abdul Rahim
%A Fatimah Azzahra Ahmad Rashid
%J Enzyme Research
%D 2012
%I Hindawi Publishing Corporation
%R 10.1155/2012/987523
%X Thermostable lipase from Geobacillus thermodenitrificans IBRL-nra was purified and characterized. The production of thermostable lipase from Geobacillus thermodenitrificans IBRL-nra was carried out in a shake-flask system at 65¡ãC in cultivation medium containing; glucose 1.0% (w/v); yeast extract 1.25% (w/v); NaCl 0.45% (w/v) olive oil 0.1% (v/v) with agitation of 200£¿rpm for 24 hours. The extracted extracellular crude thermostable lipase was purified to homogeneity by using ultrafiltration, Heparin-affinity chromatography, and Sephadex G-100 gel-filtration chromatography by 34 times with a final yield of 9%. The molecular weight of the purified enzyme was estimated to be 30£¿kDa after SDS-PAGE analysis. The optimal temperature for thermostable lipase was 65¡ãC and it retained its initial activity for 3 hours. Thermostable lipase activity was highest at pH 7.0 and stable for 16 hours at this pH at 65¡ãC. Thermostable lipase showed elevated activity when pretreated with BaCl2, CaCl2, and KCl with 112%, 108%, and 106%, respectively. Lipase hydrolyzed tripalmitin (C16) and olive oil with optimal activity (100%) compared to other substrates. 1. Introduction Lipases (triacylglycerol acylhydrolases, EC 3.1.1.3) catalyse the hydrolysis of long-chain triglycerides with the formation of diacylglycerol, monoacylglycerol, glycerol, and carboxylate, as well as the reverse reaction of the synthesis of esters formed from fatty acids and glycerols [1], present in diverse organisms including animals, plants, fungi, and bacteria. However, only microbial thermostable lipases are commercially significant for their potential use in industries, such as specialty organic syntheses [2], hydrolysis of fats and oils, modification of fats, flavor enhancement in food processing, and chemical analyses [3]. Microbial lipases also have been immensely used for biotechnological applications in dairy, detergents, and textile industries as well as surfactant and oil-processing industries. In fact they have also been widely used in pharmaceutical industries in the production of enaniometrically pure chemicals, since they have a number of unique characteristics couple with in district substrate specificity [4], stable and active in organic solvents [5], do not require cofactors [6], exhibit a high degree of regioselectivity, and possess a wide range of substrate specificity for the conversion of various unnatural substrates [2]. Lipases with molecular weight range of 19¨C60£¿kDa, belong to the ¦Á/¦Â hydrolase family. The active site is formed by a catalytic triad of Ser, Asp/Glu and His [7].
%U http://www.hindawi.com/journals/er/2012/987523/