Indian Journal of Science and Technology

Abstract

The two factors important when optimization of enzyme immobilization for the fabrication of biosensor are: activity and stability. The present study investigates the 2 factors when laccase was immobilized on various supports by different methods. Immobilization of partially purified laccase showed that enzyme expressed 100% activity when immobilized on the nitrocellulose membrane. pH and temperature optimum of immobilized laccase was 6.5 and 55°C respectively, when syringaldazine was used as a substrate. Immobilized laccase on nitrocellulose membrane was 100% stable at 4°C –30°C for three months. At 60ºC enzyme showed 50% stability after 30 min. Immobilized laccase showed best response with syringaldazine which gave reaction even at 1 to 5µM concentration. Immobilized laccase gave response to catechol, catechin and L-methyl DOPA in the range of 40 to 90, 40 to 60, 30 to 70 µM respectively. ABTS (2,2′-azino-bis (3-ethylbenzothiazoline-6-sulfonate)) also showed response to the laccase from 0.1 to 0.2 mM.
Keywords: Immobilization, laccase, nitrocellulose membrane, γ-proteobacterium