OPTIMASI pH DAN SUHU PADA REAKSI ENZIMATIS LAKASE Trichoderma asperellum LBKURCC1 HASIL FRAKSINASI PENGENDAPAN 20-80% KEJENUHAN AMMONIUM SULFAT

Abstract

Laccase is enzyme can be produced by the fungus Trichoderma asperellum LBKURCC1 that was isolated from cacao rhizosphere soil in Riau plantation area. This study aimed to determine the optimum pH and temperature for enzymatic reaction of T. asperellum LBKURCC1 laccase after purification of crude extract using precipitation ammonium sulfate with a concentration of 20-80%. The resulting precipitate was dialyzed using ultrafiltration (UF) centrifugation with 30.000 Dalton Molecular Weight Cut Off (MWCO) membrane to obtain partly purified enzymes. Enzyme activity was measured with a pH variation of acetate buffer pH 4,0; 4.0; 4.5; 5.0; 5.5 and phosphate buffer pH 6.0; 6.5; 7.0; 7.5; 8.0 and temperature 30-60oC using buffer obtained from measuring the optimum pH of laccase. Measuring the enzyme activity using the substrate 2,2'-azinobis-3- ethylbenzothiazolin-6-sulfonate (ABTS) at a wavelength 420 nm. The results showed that the optimum laccase activity was found at pH 5.5 (69.50±17.78) U/L and temperature 45oC (332.87±8.89) U/L.