| In order to learn the specific of bio-transformation of different apple phenolic compounds catalyzed by immobilized Laccase (Trametes versicolor). In this paper, white-rot fungus laccase characteristics were studied by spectrophotometry and other means, and applied to the apple pectin for removal of polyphenol decolorization for the first time, The trial results showed as follows:1. The maximum absorption wavelength of laccase-catalyzed end-product for catechin and chlorogenic acid were 442,379 nm, respectively; optimum reaction temperatures were both 55℃; optimum pH were pH6.0 and pH6.5 for catechin,pH5.5 and pH6.0 for chlorogenic acid; enzyme concentration of 0.05U mL-1 was the most efficient for 0.5 mol·L-1 catechin. And laccase catalyzed bio-transformation for both substrates fitted the Michaelis-Menten equation. Under the standand reaction (25℃), km values for catechin and chlorogenic acid were 0.1489,0.3390mol L-1, respectively; Vmax values were 212.77,28.01δA*(U*min)-1, respectively.2. Chitosan immobilized laccase with glutaraldehyde. The results indicated that the optimized conditions of immobilization of laccase could be specified as: pH 5.5, 0.2g Chitosan microspheres was activated by 5% glutaraldehyde for 8h,then added 1U/ml laccase to immobilize for 8h in the temperature of 50℃.By the analysis method of Response surface methodology(RSM),the resultd indicated that activity,concentration of glutaraldehyde, amount of enzyme, and pH were 4.9694%, 1.0096U/ml, and 5.4942 ,respectively.3. The application of chitosan immobilized laccases in the removal of polyphenol of apple pectin was studied in this article. Experiments showed that the polyphenol of apple pectin dealed with chitosan immobilized laccase in the optimized temperature 40'C for 2h decreased15%,while enzyme activity did not vary which indicated immobilized lactase was more stable than free enzyme. Therefore chitosan immobilized laccase had potential application in industrialized production of apple pectin.
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