Microbial Detection by a Glucose Biosensor Coupled to a Microdialysis Fibre

Abstract

The use of a glucose biosensor coupled to microdialysis sampling in a flow injection analysis system is described to follow the growth of Escherichia coli in a glucose-containing liquid culture medium. The experimental set-up permitted a throughput rate of 25 samples h^–1. Growth curves were modelled by a modified Gompertz equation, which permitted the determination of lag time and maximum specific growth rate. The time required to produce an appreciable variation in the biosensor response (minimum detection time, MDT) was determined. A plot of MDT versus microbial concentration was found to be linear in the range 10⁶–10¹⁰ colony forming units (cfu) ml^–1. A microbial concentration of 10⁶ cfu ml^-1 can be detected after about 5 h.