RELATIONSHIP BETWEEN ELECTROMOTIVE-FORCE AND BATCH CULTURE PROCESS OFAN IRON-OXIDIZING BACTERIUM

The electromotive force (EMF) occurring during batch culture of an iro n-oxidizing bacterium was measured, and the relationship between the t ime evolution of the EMF, substrate concentration and bacterial densit y was investigated both experimentally and theoretically. The aim was to examine whether the monitoring and control of the culture process b y measurement of the EMF and the utilization of electrical energy were possible. The measured and theoretical maximum EMF values were 288 mV and 322 mV respectively. The EMF calculated using the Nernst equation , based on the Monod equation of bacterial growth and the theoretical timecourse of the consumption of limiting substrate (FeSO4), was in go od agreement with the measured values.