Cloning, auto-induced expression by dual temperature controlling and characterization of lipase from Aurantiochytrium sp. PKU#SW7

Abstract:

[Objective] The lipase gene of Aurantiochytrium sp. PKU#SW7 was cloned and expressed in Escherichia coli, and the lipase enzymatic properties were characterized. [Methods] Sequence of lipase gene was identified with transcriptome data (Liu, et al; unpublished data). The recombinant plasmid pET30-lip was over expressed in Rosetta(DE3) by auto-induced and dual temperature control strategy. The recombinant lipase (LIP) was purified with Ni-Agarose His affinity chromatography and the enzymatic properties were further determined. [Results] A length of 873 bp lipase gene was obtained (GenBank accession number: KT305964). The optimal temperature and pH for lipase hydrolytic activity on p-NPB were 40 °C and pH 8.0, respectively. The LIP activity was increased to about 130% after treated by Ca2+ and Co2+ for 30 min. No significant inhibition of LIP activity was observed by methanol treatment. Under the optimal conditions, the LIP specific activities for p-NPP and p-NPB were 70.0±3.1 U/mg and 102.5±2.6 U/mg. [Conclusion] The LIP of Aurantiochytrium sp. PKU#SW7 possess favorable characteristics and meets the basic requirements of biodiesel catalyst.

Key words:Aurantiochytrium,Lipase, Auto-induced expression by dual temperature controlling