Production and Gelatin Entrapment of Laccase from Trametes versicolor and its Application to Quantitative Determination of Phenolic Contents of Commercial Fruit Juices

Abstract

Laccase (benzenediol: oxygen oxidoreductase; EC 1.10.3.2) is a particularly promising enzyme for several industrial fields, including food industries, since this enzyme catalyzes the oxidation of ortho and para-diphenols, amino-phenols, polyphenols, polyamines, lignins, and aryl diamines as well as some inorganic ions coupled to the reduction of molecular dioxygen to water. In this study, laccase was produced from one of the best laccase-producing organisms, Trametes versicolor. For this purpose, several phenolic acids were tested as laccase inducers. Caffeic acid and ferulic acid were determined to be the best inducers among the tested phenolic acids. Also, it was shown that laccase activity could be determined by using caffeic acid and ferulic acid as phenolic substrates by measuring the rates of oxygen consumption. Laccase was immobilized in gelatin under optimized conditions. Kinetic constants K _m and V _max for immobilized enzyme were estimated to be 74.758 μM and 0.744 μmol.ΔO₂/ml.min for caffeic acid and 0.999 μM and 57.80μ mol.ΔO₂/ml.min for ferulic acid, respectively. The immobilized enzyme exhibited the maximal activity at pH 4.5, and at 35°C. Immobilized enzymes were used for the determination phenolic contents of commercially prepared fruit juices. Caffeic acid contents of black cherry, apricot, and peach juice were determined to be 1640±33, 679±24 and 408±29 mg/L, and their ferulic acid contents were determined to be 1786±28, 800±30, and 444±28 mg/L, respectively.

Keywords:

• laccase
• Trametes versicolor
• immobilization
• gelatin
• phenolic acids
• fruit juices

ACKNOWLEDGMENT

This work was partly supported by Ege University Scientific Research Fund (2004 Fen 07).