An enzymatic membrane was prepared by co-immobilization of cholesterol oxidase and cholesterol esterase onto a new immobilization support. Polyvinyl formal resin was used to prepare enzyme membrane with the help of organic solvents. The enzymes in the ratio of (1:1) were co-immobilized on this membrane by entrapment method. The effect of cross-linking agent i.e. glutaraldehyde, on enzyme membrane was studied. The pH stability and thermal stability of the co-immobilized COE and COD were found to be higher as compared to the free enzymes. In addition, this enzyme membrane was used several times for estimation of cholesterol by colorimetric method without loss of enzyme activity. This enzyme membrane was further attached to the oxygen electrode and there was a linear relationship was observed between the oxygen consumption and cholesterol concentration. This enzyme membrane can be stored at room temperature for 30 days without any loss of activity.
Cholesterol esterase, (COE) Cholesterol oxidase (COD) and Polyvinyl formal resin (PVFR)
