Overexpression of the endo-inulinase gene from Arthrobacter sp. S37 in Yarrowia lipolytica and characterization of the recombinant endo-inulinase

The endo-inulinase gene (EnIA) from Arthrobacter sp. S37 was ligated into the expression vector pINA1317 and over-expressed in Yarrowia lipolytica Po1h. It was found that the endo-inulinase activity and specific endo-inulinase activity produced by the transformant 1317-EnIA were 16.7 U/mL and 93.4 U/mg, respectively. The recombinant EnIA was purified and characterized. The molecular weight of the purified rEnIA was 78.9 kDa. The optimal pH and temperature of the purified rEnIA were 4 and 50 °C, respectively. The purified rEnIA was stable in the temperature range of 4–40 °C and in the pH range of 2–8. The activity of rEnIA was greatly stimulated in the presence of Li+. The purified rEnIA could actively convert inulin into disaccharides.