ABSTRACT
This chapter presents a representative choice of examples illustrating the use of continuous culture as a tool for the study of mixed microbial populations. Microorganisms possess a wide variety of mechanisms for structural and functional phenotypic adaptation to their environment. In natural environments, microorganisms often grow in the presence of low concentrations of a diversity of compounds, several of which may make up combinations of homologous substrates, that is, substrates that serve a similar metabolic function, for instance, carbon sources, and nitrogen sources. Chemostat enrichment is probably the best method for selectively isolating microbial communities. The danger with laboratory model systems is undoubtedly that they may be identified with the natural system itself. Many studies have dealt with the responses of bacterial populations, growing in continuous cultures under steady state conditions, to a nutritional shift-up, either by increasing the concentration of the growth-limiting substrate or by increasing dilution rate.
