Characterization of Lectins and Bacterial Adhesins in Activated Sludge Flocs
Abstract:Bacterial lectins are carbohydrate-binding proteins that are involved in bacterial adhesion and aggregation. In order to investigate if lectins are involved in floc formation of activated sludge, Hemaagultination (HA) and HA inhibition assays were conducted on extracellular polymeric substances (EPS) extracted from activated sludges. Seven sludges from both full-scale and synthetic chemical-fed laboratory activated sludge systems were subjected to extracting EPS and lectin assay. Activated sludge EPS resulted in strong agglutination with trypsin-treated human red blood cells. While simple monosaccharides failed to exhibit the inhibition on agglutination, several glycoproteins clearly reversed agglutination, indicating that glycoprotein (oligosaccharide)-specific lectins are present in activated sludge. This inhibitory pattern was the same for both the field and laboratory-grown activated sludges, indicating that these lectins are indigenously generated by activated sludge microorganisms. The major lectin activities were found to be present in a hydrophobic region of EPS. The activities remained unaffected after heat and urea treatment of EPS but were significantly reduced by the EDTA treatment. These results share similar properties with previously studied pure culture bacterial lectins and support the conclusion that the lectin-mediated bacterial aggregation is one of the mechanisms responsible for activated sludge bioflocculation.
Document Type: Research Article
Publication date: January 1, 2008
More about this publication?
- Proceedings of the Water Environment Federation is an archive of papers published in the proceedings of the annual Water Environment Federation® Technical Exhibition and Conference (WEFTEC® ) and specialty conferences held since the year 2000. These proceedings are not peer reviewed. WEF Members: Sign in (right panel) with your IngentaConnect user name and password to receive complimentary access.
- Subscribe to this Title
- Membership Information
- About WEF Proceedings
- WEFTEC Conference Information
- ingentaconnect is not responsible for the content or availability of external websites