Crude lipase was extracted from defatted rice bran with calaium chloride and subsequently precipitated with CaCl2 solution. Effects of six kinds of metal ions on the lipase activity were investigated. Results showed that when several metal ions, including Zn2+、Fe2+ and Mg2+ with suitable concentration being of 0.01 mol/L, could enhance the lipase activity, while Ca2+、Ba2+ and Cu2+ inhibited its activity. When the concentration of metal ions (Ca2+、Ba2+ and Cu2+) ranged from 0.001mol/L to 0.1 mol/L, its activity decreased with the increase of concentration of those metal ions, but was improved by increasing the concentration of other metal ions (Zn2+, Fe2+ and Mg2+) from 0.001mol/L to 0.02 mol/L. However, further raising the concentration of Zn2+, Fe2+ and Mg2+ from 0.02 mol/L to 0.1 mol/L. will lower its activity.
