A new extracellular thermo-solvent-stable lipase from Burkholderia ubonensis SL-4: Identification, characterization and application for biodiesel production
2016
Yang, Wenjuan | He, Yaojia | Xu, Li | Zhang, Houjin | Yan, Yunjun
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. 33kDa 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 0.72mM, a kcat of 391.63s⁻¹ and a kcat/Km of 543.93s⁻¹mM⁻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.
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