Metagenomic characterization of the enhanced performance of anaerobic fermentation of waste activated sludge with CaO2 addition at ambient temperature: Fatty acid biosynthesis metabolic pathway and CAZymes

Qian Ping; Ming Zheng; Xiaohu Dai; Yongmei Li

doi:10.1016/j.watres.2019.115309

Metagenomic characterization of the enhanced performance of anaerobic fermentation of waste activated sludge with CaO₂ addition at ambient temperature: Fatty acid biosynthesis metabolic pathway and CAZymes

Water Res. 2020 Mar 1:170:115309. doi: 10.1016/j.watres.2019.115309. Epub 2019 Nov 14.

Authors

Qian Ping¹, Ming Zheng¹, Xiaohu Dai², Yongmei Li³

Affiliations

¹ State Key Laboratory of Pollution Control and Resource Reuse, College of Environmental Science and Engineering, Tongji University, Shanghai, 200092, PR China.
² State Key Laboratory of Pollution Control and Resource Reuse, College of Environmental Science and Engineering, Tongji University, Shanghai, 200092, PR China; Shanghai Institute of Pollution Control and Ecological Security, Shanghai, 200092, PR China.
³ State Key Laboratory of Pollution Control and Resource Reuse, College of Environmental Science and Engineering, Tongji University, Shanghai, 200092, PR China; Shanghai Institute of Pollution Control and Ecological Security, Shanghai, 200092, PR China. Electronic address: liyongmei@tongji.edu.cn.

PMID: 31812814
DOI: 10.1016/j.watres.2019.115309

Abstract

This study investigated the chemical and genetic mechanisms of anaerobic fermentation of waste activated sludge (WAS) with CaO₂ addition at ambient temperature. The microbial community structures, key microorganisms, functional profiles and related carbohydrate-active enzymes were further revealed according to metagenomic sequencing combining with 16S rRNA gene amplicon sequencing. Results showed that the prolonged period of alkaline condition generated from CaO₂ contributed significantly to the continuous destruction of WAS, and the oxidative environment caused by CaO₂ further enhanced flocs dissolution. This synergistic effect also significantly changed the microbial community. Oxidation contributed more than the alkaline condition to the decline of microbial diversity, while the effect of alkaline condition was greater than that of oxidation in the change of microbial community structure. The key enhanced genes associated with fatty acid biosynthesis pathways with CaO₂ addition were highlighted. Three kinds of high-abundance acetyl-CoA carboxylase genes and eleven kinds of synthetase, hydrolase, lyase and oxidoreductase genes promoted by CaO₂ were distributed throughout each branch of fatty acid biosynthesis pathway (ko00061). Moreover, carbohydrate binding modules (CBMs) and glycoside hydrolases (GHs) were the top two carbohydrate-active enzymes (CAZymes) improved by CaO₂ addition. CaO₂ can also effectively promote the function of lysozyme and the metabolism of several monosaccharides. This work provides a deep insight into the advantage of CaO₂ in promoting sludge solubilization and acidification at the genetic levels, thus expanding the application of CaO₂ in sludge treatment and resource recovery.

Keywords: Ambient temperature; Anaerobic fermentation; Calcium peroxide (CaO(2)); Carbohydrate-active enzymes; Metagenomic; Waste activated sludge (WAS).

MeSH terms

Anaerobiosis
Fatty Acids*
Fatty Acids, Volatile
Fermentation
Metabolic Networks and Pathways
RNA, Ribosomal, 16S
Sewage*
Temperature

Substances

Fatty Acids
Fatty Acids, Volatile
RNA, Ribosomal, 16S
Sewage