The continuous culture of bacteria; a theoretical and experimental study

SUMMARY: A theoretical treatment of continuous culture is given, which allows quantitative prediction of the steady-state concentrations of bacteria and substrate in the culture, and how these may be expected to vary with change of medium, concentration and flow-rate. The layout and operation of a small pilot plant for the continuous culture of bacteria are described. This plant has been operated continuously for periods of up to 4 months without breakdown or contamination of the culture. No alterations in the properties of the organisms studied have occurred during such periods of continuous culture. Results are given of a series of experiments on the continuous culture of Aerobacter cloacae in a chemically defined medium, designed to allow quantitative comparison with the results predicted by the theory. The rela-tive advantages of batch and continuous culture as production processes are discussed, and it is concluded that continuous culture may usually be expected to show a five to tenfold increase in output as compared with a batch process. The continuous culture of micro-organisms is a technique of increasing impor-tance in microbiology. The essential feature of this technique is that microbia