Print Email Facebook Twitter Impact of metal ions on structural EPS hydrogels from aerobic granular sludge Title Impact of metal ions on structural EPS hydrogels from aerobic granular sludge Author Felz, S. (TU Delft BT/Environmental Biotechnology) Kleikamp, H.B.C. (TU Delft BT/Environmental Biotechnology) Zlopasa, J. (TU Delft BT/Environmental Biotechnology) van Loosdrecht, Mark C.M. (TU Delft BT/Environmental Biotechnology) Lin, Y. (TU Delft BT/Environmental Biotechnology) Date 2020 Abstract Structural extracellular polymeric substances (structural EPS) can form stable hydrogels and are considered to be responsible for the stability of biofilms and aerobic granular sludge. Structural EPS were extracted from aerobic granular sludge and characterized for their gel-forming capacity with different alkaline earth and transition metal ions. The structural EPS hydrogels were compared to alginate hydrogels. Alginate is a well characterized polymer which is able to form stiff hydrogels with multivalent ions. The stiffness of the obtained hydrogels was measured with dynamic mechanical analysis and quantified by the Young's modulus. Furthermore the stability of structural EPS hydrogels towards disintegration in the presence of ethylenediaminetetraacetic acid (EDTA) was evaluated at pH 4.5–10.5 and compared to that of alginate, polygalacturonic acid and κ-carrageenan. The stiffness of alginate hydrogels was multiple times higher than that of structural EPS. Alkaline earth metals resulted in stiffer alginate hydrogels than transition metals. For structural EPS this trend was opposite to alginate. Independent of the pH, polysaccharide hydrogels were quickly disintegrated when being exposed to EDTA. Structural EPS hydrogels demonstrated greater stability towards EDTA and were still intact after one month at pH 4.5–8.5. It is suggested that the gelling mechanism of structural EPS is not only related to metal ion complexation of the polymers, but to a combination of interactions of multiple functional groups present in structural EPS. This study helps to further understand and characterize structural EPS from aerobic granular sludge, and therewith understand its stability and that of biofilms in general. Subject Aerobic granular sludgeBiofilmEPS analysisExtracellular polymeric substances (EPS)Hydrogel To reference this document use: http://resolver.tudelft.nl/uuid:1e86a45f-380d-4794-8f45-910677359e01 DOI https://doi.org/10.1016/j.bioflm.2019.100011 Source Biofilm, 2 Part of collection Institutional Repository Document type journal article Rights © 2020 S. Felz, H.B.C. Kleikamp, J. Zlopasa, Mark C.M. van Loosdrecht, Y. Lin Files PDF 1_s2.0_S2590207519300115_main.pdf 1.5 MB Close viewer /islandora/object/uuid:1e86a45f-380d-4794-8f45-910677359e01/datastream/OBJ/view