β-Galactosidase(β-D-galactoside galactohydrolase, E.C. 3. 2. 1. 23) from E. coli K-12 CSH 36 was immobilized on porous cellulose beads which were previously activated with tannin and p-benzoquinone. Their general properties and applicational possibities were investigated.
The most effective, enzyme immobilization was obtained when tannin and p-benzoquinone, pH 11.0, were used together as activation reagents and a period of 6 hours of activation. The optimum pH of β-galactosidase was 5.5 for free enzyme and 6. 0 for the immobilized enzyme, the optimum temperatures for native and immobilized enzyme were both 50℃. Kms of native β-galactosidase and immobilized enzyme for ONPG(o-nitrophenyl galactopyranoside) were about 4.0×10^(-4)M and 7.5×10^(-4)M, respectively. In the case of tannin : p-benzoquinone activated cellulose beads, the immobilized enzyme retained over 80% of the initial enzyme activity after 20 runs, which is very promising result far a possible industrial application.
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