ELECTROCHEMICAL BIOASSAY SYSTEM - REDOX MEASUREMENTS OF ESCHERICHIA-COLI GROWTH BY MULTICHANNEL ANALYZER

The redox responses to growth of Escherichia coli, including potential changes with and without current drain, peak current and coulombic ou tput as a function of electrode surface area, and the lag time from in oculation to mid-peak potential have been determined. Excellent reprod ucibility was established for replicate experiments under the uniform conditions prevailing in a multichannel electrochemical analyzer with automatic data acquisition. Bacterial generation of hydrogen from gluc ose followed by oxidation on the Pt anode appears to be the major elec trode reaction. Concurrent measurements of absorbance and glucose cons umption have been made, The following rate constants were obtained fro m kinetic studies: k (glucose consumption), k (E. coli growth), k (pot ential), k (current) and k (hydrogen generation). Further characteriza tion of this bioelectrochemical system was derived from the studies of increasing concentrations of glucose, E. coil adsorption to anode, si mulating redox responses with gaseous hydrogen and peroxide inhibition of the redox potential. Thus redox responses and kinetics measured in an E. coli fuel cell can be used to compare dose responses to agents and conditions that affect bacterial growth and environmental health.