Model for continuous culture which considers the viability concept

The effect of the rate of ‘natural death’ of bacteria on the steady state behaviour of continuous culture has been studied. A model which has no real biochemical basis but which gives good experimental correlation has been proposed. Populations of Acrobacter Acrogenes harvested from the chemostat at dilution rates greater than 0.1 HR^?1 were found to be over 95% viable. The effect of the rate of death on the steady state yields becomes significant only at very low dilution rates. The experimental work of other workers has also been simulated to test the validity of the model. Theoretically it is also shown that an ‘apparent’ lag in batch cultures will be observed if the innoculum is of very low viability.