TECHNOLOGY FOR REGENERABLE BIOSENSOR PROBES BASED ON ENZYME CELLULOSE-BINDING DOMAIN CONJUGATES

The application of enzyme-based biosensors for on-line bioprocess moni toring and control has been slowed by problems relating to the in situ sterilizability of the probe and the stability of the enzyme componen t. A novel technology with the potential to address both of these diff iculties is presented here, The approach is based on the reversible im mobilization of enzymes conjugated with the cellulose binding domain ( CBD) of cellulases from Cellulomonas fimi. A regenerable biosensor ele ctrode can be configured with a cellulose matrix onto which the enzyme -CBD conjugate can be repeatedly loaded (bound by the CBD) and subsequ ently eluted by perfusing the cellulose matrix with the appropriate so lution. Glucose oxidase (GOx) conjugated to CBD with glutaraldehyde wa s used in an experimental glucose biosensor to demonstrate the feasibi lity of multiple cycles of loading and elution of the conjugate. Micha elis-Menten enzyme kinetics provided an empirical model for the calibr ation of the experimental biosensor. The development of a computer-con trolled prototype glucose biosensor and a fermentation monitoring syst em based on this approach is discussed.