Effect of enzymatic hydrolysis on developing support of polyamide woven fabric for enzyme immobilization

Abstract

Polyamide fiber has been considered as a suitable support for enzyme immobilization because of its low cost, chemical and mechanical properties and ready availability in a number of different forms. In particular, polyamide fabric has highly specific surface and good elasticity. The present study aims to develop an immobilization support from polyamide fabric and to establish the optimum immobilization conditions for laccase. For this, the enzymatic hydrolysis process was introduced to the hydrolysis of polyamide, creating amino groups that immobilize enzyme molecules. When polyamide fabric was hydrolyzed by bromelain during enzymatic hydrolysis, the highest immobilization yield (68 +/- 0.7%) and relative activity (95 +/- 0.52%) of immobilized laccase were obtained. For successful enzyme immobilization, the optimal glutaraldehyde crosslinking conditions were pH of 9.0 with 10% (v/v) of glutaraldehyde concentration for 240 min at 45celcius. The most favorable immobilization conditions were as follows: pH of 6.0 with 35% (owf) of laccase concentration for 600 min at 4celcius. Under the optimum treatment conditions, the pH and thermal stability of immobilized laccase were improved. After 20 days of storage, the immobilized laccase on enzymatic hydrolyzed polyamide fabric retained approximately 30% of its initial activity. Furthermore, the immobilized laccase indicated potential reuse over 10 use cycles. The structural changes of polyamide fabric according to treatment processes were demonstrated by Fourier transform infrared spectroscopy. The changes of surface morphology were measured by scanning electron microscopy according to the multi treatment steps.