A COMMUNITY MODEL OF CILIATE TETRAHYMENA AND BACTERIA ESCHERICHIA-COLI .1. INDIVIDUAL-BASED MODELS OF TETRAHYMENA AND ESCHERICHIA-COLI POPULATIONS

The dynamics of a microbial community consisting of a eucaryotic cilia te Tetrahymena pyriformis and procaryotic Escherichia coli in a batch culture is explored by employing an individual-based approach. In this portion of the article, Part I, population models are presented. Beca use both models are individual-based, models of individual organisms a re developed prior to construction of the population models. The indiv idual models use an energy budget method in which growth depends on en ergy gain from feeding and energy sinks such as maintenance and reprod uction, These models are not limited by simplifying assumptions about constant yield, constant energy sinks and Monod growth kinetics as are traditional models of microbal organisms. Population models are gener ated from individual models by creating distinct individual types and assigning to each type the number of real individuals they represent. A population is a compilation of individual types that vary in a phase of cell cycle and physiological parameters such as filtering rate for ciliates and maximum anabolic rate for bacteria. An advantage of the developed models is that they realistically describe the growth of the individual cells feeding on resource which varies in density and comp osition. Part II, the core of the project, integrates models into a dy namic microbial community and provides model analysis based upon avail able data.