Isolation and characterization of a thermophilic lipase from Bacillus thermoleovorans ID-1

• Published in: FEMS microbiology letters 1999-10, Vol.179 (2), p.393-400
• Main Authors: Lee, Dong-Woo, Koh, You-Seok, Kim, Ki-Jun, Kim, Byung-Chan, Choi, Hak-Jong, Kim, Doo-Sik, Suhartono, Maggy T., Pyun, Yu-Ryang
• Format: Article
• Language: English
• Subjects: Bacillus thermoleovorans; Lipase; Thermophile
• ISSN: 0378-1097; 1574-6968
• DOI: 10.1016/S0378-1097(99)00440-1

A thermophilic microorganism, Bacillus thermoleovorans ID-1, isolated from hot springs in Indonesia, showed extracellular lipase activity and high growth rates on lipid substrates at elevated temperatures. On olive oil (1.5%, w/v) as the sole carbon source, the isolate ID-1 grew very rapidly at 65°C with its specific growth rate (2.50 h −1) and its lipase activity reached the maximum value of 520 U l −1 during the late exponential phase and then decreased. In addition to this, isolate ID-1 could grow on a variety of lipid substrates such as oils (olive oil, soybean oil and mineral oil), triglycerides (triolein, tributyrin) and emulsifiers (Tween 20, 40). The excreted lipase of ID-1 was purified 223-fold to homogeneity by ammonium sulfate precipitation, DEAE-Sephacel ion-exchange chromatography and Sephacryl S-200 gel filtration chromatography. As a result, the relative molecular mass of the lipase was determined to be 34 kDa on sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE). The enzyme showed optimal activity at 70–75°C and pH 7.5 and exhibited 50% of its original activity after 1 h incubation at 60°C and 30 min at 70°C and its catalytic function was activated in the presence of Ca 2+ or Zn 2+.