Properties of a thermostable extracellular lipase from Bacillus megaterium AKG-1.
An extracellular lipase isolated from Bacillus megaterium AKG-1 had an optimum activity at 55 degrees C/pH 7.0. It retained 100% activity at 50 degrees C for 30 min with a half life of 30 min at 70 degrees C. A 20-70% increase in lipase activity was observed in presence of acetone (20% v/v), DMSO (20% v/v) and isopropanol (10% v/v). The enzyme activity was 92, 98 and 107% after 24 h, on treatment with 10% (v/v) acetone, benzene and isopropanol respectively. Deoxycholic acid, sodium deoxycholate, lithocholic acid, rhamnolipid, Brij 52 and cholic acid stimulated the lipase activity by 76, 36, 24, 24, 23.6 and 13%, respectively. Addition of reducing agents like sodium sulphite, sodium metabisulphite and L-cysteine-HCl, at 10 mM concentration stimulated lipase activity by 127, 146 and 150% respectively. The lipase appeared to show enantioselectivity in hydrolyzing racemic 3-acetoxy-beta-lactam as it hydrolyzed only the (+) enantiomer.
Sekhon
Anurag
A
Molecular Genetics and Microbiology, The University of Texas at Austin 1, University Station A5000, Austin TX 78712-0162, USA.
Dahiya
Neetu
N
Tiwari
Ram P
RP
Hoondal
Gurinder S
GS
D001410:Bacillus megaterium / Q000201:enzymology / Q000378:metabolism*; D006358:Hot Temperature; D006863:Hydrogen-Ion Concentration; D007477:Ions; D008049:Lipase / Q000302:isolation & purification / Q000378:metabolism*; D008670:Metals; D012988:Soil Microbiology; D012997:Solvents; D013501:Surface-Active Agents; D013997:Time Factors
D007477:Ions; D008670:Metals; D012997:Solvents; D013501:Surface-Active Agents; D008049:Lipase