Novel sol-gel immobilization of horseradish peroxidase employing a detergentless micro-emulsion system

A novel sol-gel immobilization method employing a detergentless micro-emulsion system that consisted ofn-hexane/iso-propanol/water was developed and used to immobilize a horseradish peroxidase (HRP). Micro-sized gel powder containing enzymes was generated in the ternary solution without drying and grinding steps or the addition of detergent, therefore, the method described in this study is a simple and straightforward process for the manufacture of gel powder. The gel powder made in this study was able to retain 84% of its initial enzyme activity, which is higher than gel powders produced through other immobilization methods. Furthermore, the HRP immobilized using this method, was able to maintain its activity at or above 95% of its initial activity for 48h, whereas the enzyme activities of free HRP and HRP that was immobilized using the other sol-gel method decreased dramatically. In addition, even when in the presence of excess hydrogen peroxide, the enzyme immobilized using the novel sol-gel method described here was more stable than enzymes immobilized using the other method.