Purification and partial characterization of the thermophilic lipase produced by

CINTIA ROMERO; FLAVIA LOTO; LICIA PERA; MARIA ABDULHAMID; MARIO BAIGORI

San Miguel de Tucumán. Tucumán

Congreso; SAMIGE; 2011

Lipases (triacylglycerol acylhydrolases; EC 3.1.1.3) constitute a group of enzymes defined ascarboxylesterases that catalyze the hydrolysis (and synthesis) of long chain acylglycerols at thelipid-water interface. In recent years, lipases have received considerable attention with regard toindustrial application, since they have a number of unique characteristics such as substratespecificity, regio-specificity, and chiral selectivity.Given that such reactions are sometimes most efficiently performed at elevated temperaturesand in organic solvents, converging attempts have been made to find thermostable lipaseswhich would have advantages over labile enzymes in such applications. In recent years, anumber of thermophilic microorganisms producing thermoactive lipases and esterases havebeen purified and characterized.In this study, we describe the purification and characterization of a thermophilic lipase producedby the thermophilic strain Bacillus licheniformis, isolated from a hot spring.Screened thermophilic Bacillus strains showed activity bands in native-PAGE indicating theproduction of extracellular lipase and/or esterase. The partial 16S rDNA sequencing of theselected Bacillus strain showed the highest similarity (99%) with Bacillus licheniformis. This waschosen for lipase purification and characterization since it produced the highest lipase activity.Purification was performed with an electroelution technique. Lipase was eluted from thepolyacrylamide gel slices and the enzyme-containing solution was concentrated under vacuum.Purity was confirmed by the migration of a single band. This enzyme showed residual activitiesequal or above 100% after treatment for 1 h at: temperatures from 45 to 60°C, alkaline pH from8 to 10 and non-polar solvent (DMSO and n-hexane).Higher thermostability, higher activity at elevated temperatures, and more resistance tochemical denaturation are desirable properties of thermophilic lipases which make them idealtools in industrial and chemical processes where relatively high reaction temperatures and/ororganic solvents are used.