By screening of 15 thermophilic Bacillus strains, five strains exhibiting lipase activity were found. Among these the strain Bacillus thermocatenulatus (DSM 730) produced the highest lipase activity. The lipase proved to be inducible and extracellular and was purified 67-fold to homogenous state by hexane extraction, methanol precipitation and ion-exchange chromatography on Q-Sepharose. The molecular weight of the lipase determined by SDS-PAGE is 16 kDa. However, the lipase forms very large aggregates (N > 750 kDa) as observed after native PAGE, which makes handling of the lipase very difficult. The lipase binds almost irreversibly on different chromatography matrices e.g., Amberlite and Serolite, and is very stable in the immobilised form. The N-terminal sequence consists of 53% apolar amino acids and shows no significant homology towards other known lipase sequences. Maximum activity was found at pH 7.5-8.0 and 60-70°C with pNPP and olive oil as substrates.
|Original language||English (US)|
|Number of pages||11|
|Journal||Biochimica et Biophysica Acta (BBA)/Lipids and Lipid Metabolism|
|State||Published - Aug 25 1994|
- (B. thermocatenulatus)
- Enzyme purification