News & Events
Research Presentation
Speaker(s): Ms. Marissa Boleij (TU Delft)
When: 12 September 2017 (9.00 AM)
Where: SCELSE, B3 Meeting Room - 1
Type: Environmental Engineering Group Meetings

Extracellular polymeric substances of anammox granular sludge

Marissa Boleij, Mark van Loosdrecht, Yuemei Lin

Department of Biotechnology, Delft University of Technology, van der Maasweg 9, 2629 HZ, Delft, The Netherlands

Anammox (anaerobic ammonium oxidation) bacteria belong to the phylum of Planctomycetes. They are used in wastewater treatment plants to convert ammonium and nitrite to nitrogen gas. Because anammox bacteria have a strong tendency to grow in aggregates they are applied in granular sludge systems. To have a better understanding of the formation of the granules, it is important to elucidate the composition of extracellular polymeric substances (EPS). However, due to the limitation in the present methodologies of extraction and characterization, the EPS of anammox granules are still a black box. In this presentation the investigation of the EPS and the associated challenges are presented. The EPS was extracted from anammox granules from a full scale reactor, using an alkaline extraction. To get a high extraction yield while avoiding protein hydrolysis, different concentrations of NaOH were tested. The extracted EPS were characterized by elemental composition analysis and by quantification of the proteins and polysaccharides with the BCA and phenol-sulphuric acid assay, respectively. The polymers were further analysed using SDS-PAGE. Besides Coomassie blue staining for the detection of proteins, periodic acid-Schiff (PAS) and Alcian blue staining were applied to detect respectively neutral and acidic glycoproteins. The detection of these new polymers and the analysis of their chemical and mechanical properties can contribute to the understanding of the structure of the EPS matrix of anammox granules