title: Expression and biochemical characterization of cold-adapted lipases from Antarctic Bacillus pumilus strains.
abstract: Two lipase genes (bpl1 and bpl3) from Antarctic Bacillus pumilus strains were expressed in Bacillus subtilis. Both recombinant lipases BPL1 and BPL2 were secreted to the culture medium and their activities reached 3.5 U/ml and 5.0 U/ml, respectively. Their molecular masses apparent using SDS-PAGE were 23 kDa for BPL1 and 19 kDa for BPL3. Both lipases were purified to homogeneity using ammonium sulfate precipitation and HiTrap SP FF column and Superose 12 column chromatographies. The final specific activities were estimated to be 328 U/mg for BPL1 and 310 U/mg for BPL3. Both lipases displayed an optimum temperature of 35°C, similar to other mesophilic enzymes. However, they maintained as much as 70% and 80% of the maximum activities at 10°C. Accordingly, their calculated activation energy at a temperature range of 10-35°C was 5.32 kcal/mol for BPL1 and 4.26 kcal/mol for BPL3, typical of cold-adapted enzymes. The optimum pH of BPL1 and BPL3 was 8.5 and 8.0, respectively, and they were quite stable at pH 7.0-11.0, showing their strong alkaline tolerance. Both lipases had a preference toward medium chain length (C6-C10) fatty acid substrates. These results indicate the potential for the two Antarctic B. pumilus lipases as catalysts in bioorganic synthesis, food, and detergent industries.
authors.affiliation: Division of Biotechnology, The Catholic University of Korea, Bucheon 420-743, Republic of Korea, Faculty of Biotechnology, Atma Jaya Catholic University, Jalan Jenderal Sudirman 51, Jakarta 12930, Indonesia.
authors.forename: Ribka
authors.initials: R
authors.lastname: Litantra
authors.forename: Stefani
authors.initials: S
authors.lastname: Lobionda
authors.forename: Joung Han
authors.initials: JH
authors.lastname: Yim
authors.forename: Hyung Kwoun
authors.initials: HK
authors.lastname: Kim
mesh_terms: D000595:Amino Acid Sequence; D000864:Antarctic Regions; D001407:Bacillus / Q000201:enzymology* / Q000235:genetics / Q000302:isolation & purification / Q000378:metabolism; D001412:Bacillus subtilis / Q000235:genetics / Q000378:metabolism; D001426:Bacterial Proteins / Q000737:chemistry* / Q000235:genetics* / Q000302:isolation & purification / Q000378:metabolism; D003001:Cloning, Molecular; D003080:Cold Temperature; D015870:Gene Expression; D006863:Hydrogen-Ion Concentration; D008049:Lipase / Q000737:chemistry* / Q000235:genetics* / Q000302:isolation & purification / Q000378:metabolism; D008969:Molecular Sequence Data; D008970:Molecular Weight; D013379:Substrate Specificity
chemical_list: D001426:Bacterial Proteins; D008049:Lipase