An Apparatus for the Continuous Culture of Bacteria at Constant Population Density

Abstract

SUMMARY: A self-regulating continuous culture apparatus is described, designed for studying growth and enzyme production in bacteria which require complex media; it might also be suitable for the cultivation of suspended tissue cells. The growth vessel is a tilted cardioid-shaped flask spinning about its long axis. Aeration and mixing are achieved in such a manner that no frothing occurs and no ‘anti-foam’ agents are required. Adherent bacterial colonies do not form on the walls of the growth vessel. Samples are removed rapidly under aerobic conditions. The basal medium can be automatically augmented with special metabolites at constant concentration without contaminating the main medium reservoir. The apparatus is autoclaved in one unit after assembly. Factors governing the design of similar small-scale apparatus are discussed.