Identification and degradation of structural extracellular polymeric substances in waste activated sludge via a polygalacturonate-degrading consortium

Journal article (2023)

Authors

Zhi Yi Hu Fuzhou University
Yi Peng Lin Fuzhou University
Qing Ting Wang Fuzhou University
Yi Xin Zhang Fuzhou University
Jie Tang Fuzhou University
Shuai Wang Fuzhou University
Mark C.M. van Loosdrecht BT/Environmental Biotechnology - AS
Raymond Jianxiong Zeng Fuzhou University
Fang Zhang Fuzhou University
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Faculty
Civil Engineering & Geosciences
Copyright: © 2023 Zhi Yi Hu, Yi Peng Lin, Qing Ting Wang, Yi Xin Zhang, Jie Tang, Shuai Wang, Mark C.M. van Loosdrecht, Raymond Jianxiong Zeng, Fang Zhang, More Authors
DOI
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https://doi.org/10.1016/j.watres.2023.119800
Anaerobic digestion Waste activated sludge Structural extracellular polymeric substances Clostridium Pectate lyases Polygalacturonate-degrading consortium
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Published Date

2023

Language

English

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Faculty

Civil Engineering & Geosciences

Abstract

By maintaining the cell integrity of waste activated sludge (WAS), structural extracellular polymeric substances (St-EPS) resist WAS anaerobic fermentation. This study investigates the occurrence of polygalacturonate in WAS St-EPS by combining chemical and metagenomic analyses that identify ∼22% of the bacteria, including Ferruginibacter and Zoogloea, that are associated with polygalacturonate production using the key enzyme EC 5.1.3.6. A highly active polygalacturonate-degrading consortium (GDC) was enriched and the potential of this GDC for degrading St-EPS and promoting methane production from WAS was investigated. The percentage of St-EPS degradation increased from 47.6% to 85.2% after inoculation with the GDC. Methane production was also increased by up to 2.3 times over a control group, with WAS destruction increasing from 11.5% to 28.4%. Zeta potential and rheological behavior confirmed the positive effect which GDC has on WAS fermentation. The major genus in the GDC was identified as Clostridium (17.1%). Extracellular pectate lyases (EC 4.2.2.2 and 4.2.2.9), excluding polygalacturonase (EC 3.2.1.15), were observed in the metagenome of the GDC and most likely play a core role in St-EPS hydrolysis. Dosing with GDC provides a good biological method for St-EPS degradation and thereby enhances the conversion of WAS to methane.