Immobilization of β galactosidase from Aspergillus oryzae via immunoaffinity support

Polyclonal antibody bound cellulose support has been exploited for the immobilization and stabilization of β galactosidase from Aspergillus oryzae. Immunoaffinity bound β galactosidase retained 96.5% of the initial activity on the support. Immobilized β galactosidase showed broad-spectrum pH optima, pH 4.6–5.5 and temperature at 50–60 °C whereas the soluble enzyme exhibited activity peak at pH 4.6 and 50 °C. Immunoaffinity bound enzyme preparation was quite stable to thermal denaturation and it retained 72% activity after 4 h incubation at 60 °C whereas under these conditions the soluble β galactosidase lost almost its full activity. IgG-cellulose immobilized β galactosidase was quite stable against the inactivation caused by proteolytic enzymes; trypsin and pepsin. Moreover, this immobilized enzyme preparation retained 64%, 71% and 65% activity in the presence of 4.0 M urea, 5% CaCl2 and 5% galactose. IgG-cellulose bound β galactosidase exhibited 80% of its original activity after 2 months storage at 4 °C while the soluble enzyme showed only 35% of the initial activity. After 10th repeated use immobilized β galactosidase retained 46% activity.