-The objective of this work was to study enzyme immobilization on chitosan activated with glutaraldehyde, aiming to produce a cheap biocatalyst. Two different immobilization strategies were studied: one-point and multipoint covalent attachment to the solid matrix. The multipoint covalent attachment derivative had an 82% immobilization yield. It was 4.9-fold more stable than the free enzyme at 50°C and 4.5-fold more stable than soluble enzyme at pH 10.0. The one-point derivative had an 85% immobilization yield. It was 2.7-fold more stable than the free enzyme at 50°C and 3.8-fold more stable than soluble PGA at pH 10.0. Results indicated that chitosan can be loaded with PGA above 330 IU/g. Intraparticle diffusive effects, however, limited hydrolysis of penicillin G catalyzed by those derivatives at 37°C and 25°C. Operational stability assays were performed and the multipoint derivative exhibited a half-life of 40 hours.

RESUMO -Foram produzidos catalisadores contendo óxidos de ferro e cobre, na proporção 60:40 (Fe2O3:CuO -% em massa), por um método sol gel, em 5 temperaturas de calcinação: 450, 500, 600, 700 e 800°C. Os catalisadores foram caracterizados e utilizados em processo oxidativo avançado para degradação do corante de azul de metileno. A amostra calcinada a 600°C apresentou melhor eficiência. Os resultados revelaram a obtenção da ferrita de cobre (CuFe2O4), além de hematita (-Fe2O3), magnetita (Fe3O4) e tenorita (CuO). Obteve-se 100% de remoção da cor, em 240min, partindo-se de uma solução inicial com 50mg/L de corante, pH 6,0, 1g/L de catalisador e 300 mg/L de H2O2. A mesma eficiência foi obtida tanto para dois ciclos de reação demonstrando a elevada estabilidade do catalisador produzido.