Purification and Characterization of an Extracellular Lipase Produced by Aspergillus oryzae ST11 as a Potential Catalyst for an Organic Synthesis

The lipase producing Aspergillus sp. ST11 was identified by molecular and morphological methods. primers ITS1/ITS4 were used for amplifying the ITS region. It showed that strain grouped with oryzae flavus (98 % bootstrap value). colony morphology of on malt extract agar Czapek yeast a characteristic A. oryzae. Therefore, it as ST11. produced purified characterized. purification steps involved precipitation chilled acetone separation column chromatography, HiTrap® Q HP Toyopearl Butyl-650M, respectively. After purification, activity increased 13 fold 7.9 yield. Its mass 25 kDa. stable at pH between 5.0 - 8.0 had optimum 7.5. 30 °C 37 °C. promoted in presence Mg2+ but greatly decreased Co2+, Cu2+, Hg2+ Zn2+. Surfactants (Triton X-100, Tween-80, Tween-20, arabic gum, sodium dodecyl sulfate) negative effects activity, while inhibitors (PMSF, EDTA, β-mercaptoethanol) did not reduce significantly. Polar solvents, such methanol ethanol, much effect compared to non-polar hexane isooctane. concentrated from catalyze transesterification gave highest bioconversion (90 %) after 24 h. HIGHLIGHTS Extracellular could be applied many applications which is more flexible use whole-cell biocatalysts High stability toward wide range temperature obtained this extracellular shows capability produce high biodiesel natural oil GRAPHICAL ABSTRACT