DEVELOPMENT OF A SIMPLE DETECTOR FOR MICROBIAL-METABOLISM, BASED ON APOLYPYRROLE DC RESISTOMETRIC DEVICE

A simple device for the detection of metabolic effects was constructed based on a conducting polymer (polypyrrole) coated with an agarose la yer containing immobilised yeast cells. A galvanostatic potentiometric method was used to measure the resistance of the sensor, thus minimis ing interferences from fluctuations in solution conductivity. The resu lting biosensor was used as a simple indicator of yeast metabolism. It responded within 20 minutes to increases in the glucose concentration by decreased resistance (40% per 5 g/l). When the metabolism was inhi bited by a toxic substance the response disappeared. The device could be reconditioned by washing off the layer with hot water, followed by the application of a new agarose layer with fresh cells. Because the m anufacture of the device is simple and the measuring principle is unco mplicated, it is specially suited for mass production for quick field tests.