Model of a chemostat utilising phenol as inhibitory substrate

A pure culture of Acinetobacter lwoffi was grown in a batch and continuous culture using phenol as the limiting substrate. Five kinetic models were applied to the data to determine the kinetic parameters governing growth of the organisms. A non-linear leastsquares technique was used to fit the data to the different functions. No significant differences were found on statistical basis between the models and so a choice was made on the grounds of mathematical simplicity. The so-called ‘Haldane function’ was chosen as the best and utilised in the model describing the steady-state behaviour of the chemostat. This model takes into account the inhibitory character of phenol and also the maintenance energy of the bacteria. Analysis of local stability shows that one can expect to obtain three steady states of which one is the trivial washout state, another is unstable and the third is a high conversion stable steady state.This model was tested with a pure culture of Acinetobacter lwoffi and phenol inlet concentrations of 200, 500 and 1000 mgl^?1. Good agreement was found between the model and the results of the continuous experiments.