Study of electron transfer mechanism and kinetic of biofilm on modified nickel electrodes

The attachment and biofilm formation by bacteria on surfaces are of interest due to its potential in microbial fuel cell, bioremediation and corrosion. Surface topography, one of the factors that affect the extent of bacteria colonization is being studied. This work investigates the initial attachment of Escherichia coli on microstructure modified nickel electrodes. The experiments explore the effect of different glucose concentration as well. The electrochemical set up included, a stirred three-electrode anaerobic bioreactors controlled by potentiostats and non-destructive electrochemical techniques to study the electron transfer mechanism and kinetics of biofilm. Micro-structured electrode has a significant improvement in the current measured by the chronoamperometry. Micro-structured electrode also reported lower impedance measured by electrochemical impedance spectroscopy. The electron transfer is found to be mediated by an exogenous catalyst, 2-Hydroxy-1,4-naphthoquinone as revealed by cyclic voltammetry. As suggested by electrochemical observations, the glucose concentration is significant in determining the colonization of E. coli on electrode surface. In conclusion, the micro-structured electrode provides surfaces that enhance the electron transfer activity on the surface. This study employed various electrochemical techniques to study the electron transfer mechanism and kinetics without disturbing the formation of biofilm and provide a framework for similar studies with other species.Bachelor of Engineering (Environmental Engineering