AN AUTOCLAVABLE GLUCOSE BIOSENSOR FOR MICROBIAL FERMENTATION MONITORING AND CONTROL

The design, construction, and characterization of a prototype-regenera ble glucose biosensor based on the reversible immobilization of glucos e oxidase (GOx) using cellulose binding domain (CBD) technology is des cribed. GOx, chemically linked to CBD, is immobilized by binding to a cellulose matrix on the sensor-indicating electrode. Enzyme immobiliza tion can be reversed by perfusing the cellulose matrix with a suitable eluting solution. An autoclavable sensor membrane system is employed which is shown to be practical for use in real microbial fermentations . The prototype glucose biosensor was used without failure or deterior ation during fed-batch fermentations of Escherichia coli reaching a ma ximum cell density of 85 g (dry weight)/L. Medium glucose concentratio n based on sensor output correlated closely with off-line glucose anal ysis and was controlled manually at 0.44 +/- 0.2 g/L for 2 h based on glucose sensor output. The sensor enzyme component could be eluted and replaced without interrupting the fermentation. To our knowledge, no other in situ biosensor has been used for such an extended period of t ime in such a high-cell-density fermentation. (C) 1995 John Wiley & So ns, Inc.