Laboratory Growth Systems in Biofilm Research

The huge variety of ecosystems that we collectively refer to as biofilm is reflected by the numerous different systems available to grow them in the laboratory. The relationship between in situ systems, microcosms and laboratory models is defined and discussed. The first two represent holistic approaches designed to assess the structure and function of particular biofilms: the last is analytical and reductionist, aiming to isolate specific functions of biofilms in order to understand properties that can apply to biofilm in general. Properties of a model can be completely understood whilst this is unlikely with natural ecosystems because of the possibility of unculturable species which could play an unrecognised but important part in its structure and function. A range of systems is reviewed. These include simple surfaces exposed to nutrient in different ways, flow systems such as the Robbins device and constant shear devices such as the Rototorque and the Fowler cell adhesion measurement module. The constant depth film fermenter (CDFF) is described as are membrane based models including the membrane biofilm and the perfused biofilm reactors. Some examples of microcosms are described. The concept and value of steady state biofilm is introduced in terms of the CDFF and of fluidised bed reactors. A number of commercially available film fermenters are listed in the appendix