Extraction of structural extracellular polymeric substances from aerobic granular sludge

Felz, S.; Al-Zuhairy, S.H.K.; Aarstad, Olav Andreas; van Loosdrecht, Mark C.M.; Lin, Y.

doi:10.3791/54534

Extraction of structural extracellular polymeric substances from aerobic granular sludge

Title

Extraction of structural extracellular polymeric substances from aerobic granular sludge

Author

Felz, S. (TU Delft BT/Environmental Biotechnology)
Al-Zuhairy, S.H.K. (TU Delft BT/Environmental Biotechnology)
Aarstad, Olav Andreas (Norwegian University of Science and Technology (NTNU))
van Loosdrecht, Mark C.M. (TU Delft BT/Environmental Biotechnology)
Lin, Y. (TU Delft BT/Environmental Biotechnology)

Date

2016-09-26

Abstract

To evaluate and develop methodologies for the extraction of gel-forming extracellular polymeric substances (EPS), EPS from aerobic granular sludge (AGS) was extracted using six different methods (centrifugation, sonication, ethylenediaminetetraacetic acid (EDTA), formamide with sodium hydroxide (NaOH), formaldehyde with NaOH and sodium carbonate (Na₂CO₃) with heat and constant mixing). AGS was collected from a pilot wastewater treatment reactor. The ionic gel-forming property of the extracted EPS of the six different extraction methods was tested with calcium ions (Ca²⁺). From the six extraction methods used, only the Na₂CO₃ extraction could solubilize the hydrogel matrix of AGS. The alginatelike extracellular polymers (ALE) recovered with this method formed ionic gel beads with Ca²⁺. The Ca²⁺-ALE beads were stable in EDTA, formamide with NaOH and formaldehyde with NaOH, indicating that ALE are one part of the structural polymers in EPS. It is recommended to use an extraction method that combines physical and chemical treatment to solubilize AGS and extract structural EPS.

Subject

Aerobic granular sludge
Alginate-like extracellular polymers (ALE)
Biofilm
Biofouling
Environmental sciences
Extracellular polymeric substances (EPS)
Extraction
Functional polymer
Hydrogel
Structural polymer