Abstract
Direct examination of the bacteria in industrial aquatic systems has revealed that they adopt the same mode of growth, in thick sessile biofilms, that is predominant in natural aquatic systems. As in the natural systems, these sessile bacteria grow in structured consortia in which anaerobic corrosion-causing bacteria are shielded from oxygen, and from antibacterial factors, by the thick overlying biofilm whose cells consume oxygen and whose exopolysaccharide matrices act as an ion exchange resin to limit the penetration of charged molecules Present methods for the detection of corrosion-causing bacteria, and for the assessment of biocide efficacy, depend on examinations of the planktonic (floating) bacteria in the flowing phase, and we have shown that these planktonic cells are only intermittently present and that they are relatively sensitive to current commercial biocides. We have developed a linear flow Robbins Device and a three-dimensional glass matrix model, and these systems promote sessile bacterial growth and provide mature well-protected biofilms that closely resemble the predominant bacterial mode of growth in industrial systems and thus provide an excellent and realistic basis for the assessment of biocide efficacy against sessile bacteria in biofilms.
