An immobilised catalase peroxidase from the alkalothermophilic Bacillus SF for the treatment of textile-bleaching effluents.

Abstract

A catalase peroxidase (CP) from the newly isolated Bacillus SF was used to treat textile-bleaching effluents. The enzyme was stable at high pH values and temperatures, but was more sensitive to deactivation by hydrogen peroxide than monofunctional catalases. Based on the Michaelis-Menten kinetics of the CP, a model was developed to describe its deactivation characteristics. The enzyme was immobilised on various alumina-based carrier materials with different shapes and the specific activity increased with the porosity of the carrier. The shape of the carrier had an important influence on the release of oxygen formed during the catalase reaction from the packed-bed reactor and Novalox saddles were found to be the most suitable shape. Bleaching effluent was treated in a horizontal packed-bed reactor containing 10 kg of the immobilised CP at a textile-finishing company. The treated liquid (500 l) was reused within the company for dyeing fabrics with various dyes, resulting in acceptable colour differences of below Delta E*=1.0 for all dyes.