ABSTRACT
As early as 1940, Heukelekian and Heller (1940) noted that growth of microorganisms on surfaces provided a competitive advantage in aquatic systems. Jones et al. (1969) characterized the slime layers of aquatic bacteria, contributing important information on biofilm structure and new procedures for biofilm characterization. Characklis (1973a), reviewed the role of slimes in natural and man-made aquatic systems, noting slimes to be the cause of marine fouling, to increase fluid frictional resistance in pipelines, to affect the heat transfer properties of heat exchangers, and to contribute to scale up problems in biological reactors. Characklis (1973b) also presented several case studies where pipelines in industrial water systems had suffered significant losses in capacity due to microbial slimes. He noted also that though chlorine had been used extensively in process water systems, it was often ineffective in destroying attached slime. Costerton et al. (1978) proposed that bacterially produced exopolymers were important in attaching bacteria to inert surfaces in aquatic and in many other systems (human and animal
tissues, for example). They argued that attachment would be advantageous in providing a constant supply of nutrients and a mechanism that would resist removal from the system (adhesion). These and other early papers document the importance of biofilms in microbial growth and industrial fouling and understanding of biofilm processes has continued to expand significantly.
