Author Description

Microbial extracellular polymeric substances (EPS) provide the structural matrix for all microbial aggregates such as biofilms, flocs and sludge, and are of great technical and ecological importance. EPS provide and form the space between biofilm cells, mediating both cohesion and adhesion. They serve as a multipurpose functional matrix for microbial communities, which allows the establishment of stable microconsortia. The EPS matrix governs diffusional and convectional mass transport because it occurs in various densities, including void spaces such as pores and channels. This creates different types of physico-chemical gradients, providing habitats in which aerobic and anaerobic organisms can coexist in close proximity and largely independent of the conditions in the water phase. Major aspects of EPS include mechanical stability, as in the case of biofouling when unwanted biofilms have to be removed, and the stability of biofilms in bioreactors; interaction with substrata in bioleaching, biocorrosion, and biodeterioration; sorption capacity for dissolved and particulate substances (biosorption), representing both a sink and source of sorbed material; enhanced resistance of biofilm organisms to biocides. The 25 peer-reviewed articles selected for these proceedings provde both a starting point for newcomers to the field and a state-of-the-art survey for the more experienced. With a diversity of approaches, ranging from sophisticated microanalysis to industrial applications, these papers provide a broad understanding of EPS from the viewpoints of microbiologists, polymer scientists, chemists and engineers, and showing how EPS may be seen as the key to understanding and controlling all forms of microbial aggregates.