Experimental Biofilms and Their Applications in the Study of Environmental Processes

The trend in research in recent years has been to extrapolate results from studies of planktonic bacteria into environmental systems. This method of studying planktonic bacteria under in vitro conditions has undoubtedly yielded important data in a wide range of areas; however, the examination of several environmental habitats, extreme or otherwise, such as a drinking water pipeline has revealed only relatively low numbers of planktonic cells. In aquatic systems the biofilm bacterial count per square centimeter of surface has been estimated to be approx 1000-fold higher than the corresponding planktonic count per cubic centimeter (1 ). Surface colonization by microorganisms was first recognized as significant as early as 1943 (2 ), and there is now a realization that we need to study microorganisms not only as biofilms but also in the context of the biofilm interactions with their immediate surroundings and the influences they exert on the environment. The environment has a significant effect on the metabolic activities of bacteria, and studies of biofilm bacteria represent the best tool for examining growth in natural and pathogenic ecosystems (3 ). The study of biofilms is relevant to a wide range of areas, and a multidisciplinary approach is the most productive route forward in the quest to understand the interactions occurring not only between the cells and the surfaces to which they adhere, but between the microcolonies that coexist within multispecies biofilms (4 ).