A new extracellular thermo-solvent-stable lipase from Burkholderia ubonensis SL-4: Identification, characterization and application for biodiesel production

• A new lipase SL-4 of Burkholderia ubonensis SL-4 was more stable at 50 °C and pH 8.5.
• Lipase SL-4 was activated by Ca2+ or Mn2+, but inhibited by EDTA, PMSF, DTT and β-ME.
• Lipase SL-4 had non-ionic detergent- and organic solvent-stability.
• Liquid lipase SL-4 could catalyze soybean oil to biodiesel at a yield rate of 92.24%.

In the present study, a new lipase SL-4 from Burkholderia ubonensis SL-4, was purified by 80% ammonium sulphate precipitation, Q Sepharose FF anion exchange and Superdex 75 gel filtration chromatography finally leading to 68.5-fold purification and 13.34% recovery. It had a molecular mass of ca. 33 kDa and the whole gene (1095-bp) was cloned by using degenerate primers. Amino acid sequence analysis revealed that lipase SL-4 is a new member of subfamily I.2 lipases. Lipase SL-4 exhibited optimum activity toward p-NP myristate (C14) at pH 8.5 and 65 °C with a Km of 0.72 mM, a kcat of 391.63 s−1 and a kcat/Km of 543.93 s−1 mM−1. It had good thermostability at 50 °C and pH 8.5, and could be activated strongly by Ca2+ and Mn2+, but inhibited by some transition metal ions and EDTA, PMSF, DTT and β-ME. Additionally, lipase SL-4 possessed non-ionic detergent stability and organic solvent stability. When preliminarily employed to catalyze soybean oil for biodiesel production, the liquid lipase SL-4 could attain a conversion ratio of 92.24% in a solvent-free system. These results demonstrate that the new thermo-solvent-stable lipase possesses an attractive potential for biotechnological applications as biocatalyst, especially for biodiesel production.

Figure optionsDownload as PowerPoint slide