STUDY ON BIOSYNTHESIS OF LACCASE ENZYME FROM FUNGI AND APPLICATION OF HYDROLYSIS OF TEA LEAVES TO OBTAIN BIOACTIVE POLYPHENOLS

Abstract

Laccase (EC 1.10.3.2) is a poly copper oxidase found in plants, fungi, and bacteria.  In this study, 21 fungal strains were screened for laccase activity, strain Clitopilus Sp. BV8 showed the highest activity at 7,943.1 U/L. Fungal strains were fermented for 7 days on medium containing the following components: MgSO₄ (0.5 g/L); KH₂PO₄ (1.5 g/L); glucose (5 g/L); pH 6.0, tomato (2%), urea (2 g/L) and cultured at 25^oC under the condition of continuous shaking at 200 rpm, the highest laccase activity was 65 U/mL. Crude laccase enzyme was concentrated from the culture solution with optimum temperature and pH at 40^oC and pH 5.0, respectively. Total polyphenol content released and antioxidant activity from green tea leaf extract supported by laccase enzyme was also evaluated. The results showed that in optimal conditions for hydrolysis of tea leaves in 18 hours, the enzyme/substrate ratio was determined to be 5.0 U/gds at pH 5 at 40^oC. Total polyphenol content and antioxidant activity reached the highest values of 136.15 mgGAE/g and 78.05%, respectively.