Abstract: A novel photocrosslinked poly(vinyl alcohol) hydrogel was prepared and applied to entrap β-lactam penicitllinase.The properties of the hydrogel and immobilized enzyme were thoroughly investigated. Results show that the hydrogel is very suitable for the immobllization of β-lactam penieillinase.The stabilities of the immobilized enzyme to PH value of the medium, temperature and storage are better than those of the free β-laotam penioilllnaee. Also the immobilized enzyme membrane is connected to a pH-sensitive field effect transistor to form a penieillin-sensitive biosensor. The specifications of the resulting biosensor are as follows:response time less than 60sec, sensitivity to penicillin larger than 3mV/mM,1inear response range of 0~16mM, and very good storage stability.When it is applied to determine the penicillin content of the fermenting mixture during the production process, the results are found to conform to those obtained by the conventional iodine titration.

Key words: penicillinase, biosensor, poly (vinyl alcohol), immobilized enzyme