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

•∼22% of bacteria were identified in WAS to produce the structural EPS (St-EPS).•A polygalacturonate-degrading consortium (GDC) is enriched with a good COD balance.•The percentage of WAS destruction increased from 11.5% to 28.4% by dosing with GDC.•The genus clostridium (17.1%) was finally identifie...

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Veröffentlicht in:Water research (Oxford) 2023-04, Vol.233, p.119800-119800, Article 119800
Hauptverfasser: Hu, Zhi-Yi, Lin, Yi-Peng, Wang, Qing-Ting, Zhang, Yi-Xin, Tang, Jie, Hong, Si-Di, Dai, Kun, Wang, Shuai, Lu, Yong-Ze, van Loosdrecht, Mark C.M., Wu, Jianrong, Zeng, Raymond Jianxiong, Zhang, Fang
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Sprache:eng
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Zusammenfassung:•∼22% of bacteria were identified in WAS to produce the structural EPS (St-EPS).•A polygalacturonate-degrading consortium (GDC) is enriched with a good COD balance.•The percentage of WAS destruction increased from 11.5% to 28.4% by dosing with GDC.•The genus clostridium (17.1%) was finally identified as the key bacterium in GDC.•Pectate lyases (EC 4.2.2.2 and 4.2.2.9) were encoded in GDC to hydrolyze St-EPS. 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. [Display omitted]
ISSN:0043-1354
1879-2448
DOI:10.1016/j.watres.2023.119800