The water-soluble fraction of extracellular polymeric substances from a resource recovery demonstration plant: characterization and potential application as an adhesive

Le Min Chen; Özlem Erol; Young Hae Choi; Mario Pronk; Mark van Loosdrecht; Yuemei Lin

doi:10.3389/fmicb.2024.1331120

The water-soluble fraction of extracellular polymeric substances from a resource recovery demonstration plant: characterization and potential application as an adhesive

Front Microbiol. 2024 Feb 26:15:1331120. doi: 10.3389/fmicb.2024.1331120. eCollection 2024.

Authors

Le Min Chen¹, Özlem Erol², Young Hae Choi², Mario Pronk^{1

3}, Mark van Loosdrecht¹, Yuemei Lin¹

Affiliations

¹ Department of Biotechnology, Delft University of Technology, Delft, Netherlands.
² Natural Products Laboratory, Institute of Biology, Leiden University, Leiden, Netherlands.
³ Royal HaskoningDHV, Amersfoort, Netherlands.

Abstract

Currently, there is a growing interest in transforming wastewater treatment plants (WWTPs) into resource recovery plants. Microorganisms in aerobic granular sludge produce extracellular polymeric substances (EPS), which are considered sustainable resources to be extracted and can be used in diverse applications. Exploring applications in other high-value materials, such as adhesives, will not only enhance the valorization potential of the EPS but also promote resource recovery. This study aimed to characterize a water-soluble fraction extracted from the EPS collected at the demonstration plant in the Netherlands based on its chemical composition (amino acids, sugar, and fatty acids) and propose a proof-of-concept for its use as an adhesive. This fraction comprises a mixture of biomolecules, such as proteins (26.6 ± 0.3%), sugars (21.8 ± 0.2%), and fatty acids (0.9%). The water-soluble fraction exhibited shear strength reaching 36-51 kPa across a pH range of 2-10 without additional chemical treatment, suggesting a potential application as an adhesive. The findings from this study provide insights into the concept of resource recovery and the valorization of excess sludge at WWTPs.

Keywords: adhesive; aerobic granular sludge; extracellular polymeric substances; resource recovery; shear strength.

Grants and funding

The author(s) declare financial support was received for the research, authorship, and/or publication of this article. This research was financially supported by the SIAM Gravitation Grant 024.002.002 from the Netherlands Organization for Scientific Research, TKI Chemie 2017 (co-funded by Royal HaskoningDHV), and the Dutch Ministry of Economic Affairs and Climate Policy. The glycosyl composition analysis performed at CCRC, the University of Georgia, was supported by the U.S. Department of Energy, Office of Science, Basic Energy Sciences, Chemical Sciences, Geosciences, and Biosciences Division, under award #DE-SC0015662.