Purification And Characterization Of Cholesterol Esterase From Rhodococcus Sp.

The significant functions of cholesterol esterase(COE, EC3.1.1.13) in food processing and medical assay were recognized gradually and showed more and more potential. In this paper, four topics were investigated: screening and identification the strain produces cholesterol esterase, optimization of cholesterol esterase-forming conditions from Rhodococcus sp., purification and identification of cholesterol esterase from Rhodococcus sp., characterization of cholesterol esterase.Strain one clone that could produce cholesterol esterase was screened from 21clones. After been identificated, could know it was Rhodococcus sp. Rhodococcus sp. is a clone of polymorphous gram positive bacteria, orange thalli, inertial biochemical reaction, cannot ferment any glucide or alcohols. The result of drug sensitive test shows that: Rhodococcus sp. is sensitively with penitricin, vancomycin, and non-sensitive with penicillin.Cholesterol esterase-forming conditions of Rhodococcus sp. were investigated. The results were obtained as follow: cholesterol esterase from Rhodococcus sp. was inducible enzyme, and extra-cellular enzyme activity was higher than intra-cellular enzyme. Oleic acid and lecithin, the substrates of the cholesterol esterase, were the best carbon sources, and they are also the best inducer. Peptone and Beef-extract were the best nitrogen sources for enzyme formation. The optimization of cultivation conditions was selected through...