This Article Full Text Full Text (PDF) Alert me when this article is cited Alert me if a correction is posted Services Similar articles in this journal Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Reprints and Permissions Copyright Information Books from ASM Press MicrobeWorld Citing Articles Citing Articles via HighWire Citing Articles via Google Scholar Google Scholar Articles by McSwain, B. S. Articles by Wilderer, P. A. Search for Related Content PubMed PubMed Citation Articles by McSwain, B. S. Articles by Wilderer, P. A. Agricola Articles by McSwain, B. S. Articles by Wilderer, P. A.

 Previous Article  |  Next Article 

Applied and Environmental Microbiology, February 2005, p. 1051-1057, Vol. 71, No. 2
0099-2240/05/$08.00+0     doi:10.1128/AEM.71.2.1051-1057.2005
Copyright © 2005, American Society for Microbiology. All Rights Reserved.

Composition and Distribution of Extracellular Polymeric Substances in Aerobic Flocs and Granular Sludge

B. S. McSwain,^1,2* R. L. Irvine,¹ M. Hausner,² and P. A. Wilderer²

Department of Civil Engineering and Geological Sciences, University of Notre Dame, Notre Dame, Indiana,¹ Institute of Water Quality Control and Waste Management, Technical University of Munich, Garching, Germany²

Received 6 July 2004/ Accepted 27 August 2004

Extracellular polymeric substances (EPS) were quantified in flocculent and aerobic granular sludge developed in two sequencing batch reactors with the same shear force but different settling times. Several EPS extraction methods were compared to investigate how different methods affect EPS chemical characterization, and fluorescent stains were used to visualize EPS in intact samples and 20-µm cryosections. Reactor 1 (operated with a 10-min settle) enriched predominantly flocculent sludge with a sludge volume index (SVI) of 120 ± 12 ml g^–1, and reactor 2 (2-min settle time) formed compact aerobic granules with an SVI of 50 ± 2 ml g^–1. EPS extraction by using a cation-exchange resin showed that proteins were more dominant than polysaccharides in all samples, and the protein content was 50% more in granular EPS than flocculent EPS. NaOH and heat extraction produced a higher protein and polysaccharide content from cell lysis. In situ EPS staining of granules showed that cells and polysaccharides were localized to the outer edge of granules, whereas the center was comprised mostly of proteins. These observations confirm the chemical extraction data and indicate that granule formation and stability are dependent on a noncellular, protein core. The comparison of EPS methods explains how significant cell lysis and contamination by dead biomass leads to different and opposing conclusions.

---

* Corresponding author. Mailing address: Institute of Water Quality Control and Waste Management, Technical University of Munich, 85748 Garching b., Munich, Germany. Phone: 49-89-289-13715. Fax: 49-89-289-13718. E-mail: bmcswain{at}nd.edu.

---

Applied and Environmental Microbiology, February 2005, p. 1051-1057, Vol. 71, No. 2
0099-2240/05/$08.00+0     doi:10.1128/AEM.71.2.1051-1057.2005
Copyright © 2005, American Society for Microbiology. All Rights Reserved.

This article has been cited by other articles:

• Weber, S. D., Ludwig, W., Schleifer, K.-H., Fried, J. (2007). Microbial Composition and Structure of Aerobic Granular Sewage Biofilms. Appl. Environ. Microbiol. 73: 6233-6240 [Abstract] [Full Text]  
• Ishii, S., Kosaka, T., Hori, K., Hotta, Y., Watanabe, K. (2005). Coaggregation Facilitates Interspecies Hydrogen Transfer between Pelotomaculum thermopropionicum and Methanothermobacter thermautotrophicus. Appl. Environ. Microbiol. 71: 7838-7845 [Abstract] [Full Text]