Lipases in the castor bean seed of Chinese varieties: Activity comparison, purification and characterization

Abstract

The lipase activities in the three main Chinese castor bean varieties [ZiBi 05 (ZB 5), TongBi 06 (TB 6), JinBi 02 (JB 2)] were investigated. Two lipases were found in extracts from the endosperms of all the three varieties. One lipase is located in the lipid bodies, showing higher activity at pH 4.5 and exhibiting the highest activity at day 1 of germination. The other lipase is located in the particulates, showing higher activity at pH 9.5 and particularly active at day 4 of germination. The lipid bodies from ZB 5 show the highest lipase activity at day 1 and pH 4.5 among the three varieties during the 8 d of germination. The acid lipase located in the lipid bodies of ZB 5 of germination 1 d was purified to homogeneity by DEAE-sepharose CL-6B and butyl-sepharose CL-4B chromatography after isolation, delipidation and solubilization, with a purification factor of 16.1 and overall activity recovery of 17.7%. The characterizations (such as optimum pH, pH stability, optimum temperature, thermal stability, effect of metal ions, organic solvents stability, substrate specificity) of the purified acid lipase were conducted in detail. A combination of the characterized properties may make this enzyme a useful biocatalyst for industrial application.