Effect of growth phase and metabolic activity on the surface charge of Escherichia coli K-12 and on its adhesion to quartz and lepidocrocite

Abstract

There are a number of bacteria associated with livestock, one of which is Escherichia coli 157:H7, a pathogenic bacterium often found associated with animal feces, which has the potential to contaminate groundwater in many rural areas. Adhesion onto soil particles is also an important biogeochemical process controlling bacterial transport that is influenced by a number of interrelated variables including pH, ionic strength, solution chemistry, soil mineralogy, bacterial growth phase and metabolic activity. The main objectives of this thesis were to first assess the surface reactivity of E. coli K-12 (a model non-pathogenic bacterium) as a function of bacterial growth phase and activity and second, to determine the extent of E. coli adhesion to quartz and Fe-oxide, two common soil minerals, as a function of pH, using batch experiments. The titration results showed that lepidocrocite had the highest buffering capacity, then bacteria, and quartz the lowest. (Abstract shortened by UMI.)