Improvements in the characteristics of rennet bound on porous glass.

The residual activity (i.e. coagulating activity of the immobilized enzyme as % of that of the free enzyme) of rennet immobilized by diazotization on porous glass balls was increased from about 11% to 38.3% by adding serum albumin and to 23.7% by adding glutaraldehyde (to replace diazotization) to the binding medium. The serum albumin also increased the stability of the immobilized rennet during storage: after 14 days, 42.2% of its initial activity was retained. Drying the glass balls (for 12 h at 110 deg C) after silanization also improved the stability of the enzyme. The effects of various other factors (e.g. binding medium and binding time) were also studied. As a result of the improvements achieved, industrial application of immobilized rennet is envisaged.