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Underlying function regulators of anaerobic granular sludge: Starvation and dormancy
Wenda Chen1, Yihao Jin1, Dongdong Xu1
1Department of Environmental Engineering, College of Environmental & Resource Sciences, Zhejiang University, Hangzhou, China.
The Science of the Total Environment
|October 18, 2021
Summary
Anaerobic granular sludge (AnGS) enters dormancy when substrate supply stops, with microorganisms sporulating. Upon restart, AnGS recovers function, but gas production is delayed, showing dormancy stabilizes the microbial community.
Area of Science:
- Environmental microbiology
- Anaerobic digestion technology
Background:
- Anaerobic granular sludge (AnGS) is crucial for anaerobic granular sludge bed systems.
- Understanding AnGS response to starvation is vital for process stability.
Purpose of the Study:
- Investigate the effects and mechanisms of substrate starvation on AnGS function.
- Elucidate the role of microbial dormancy in AnGS stability.
Main Methods:
- Simulated starvation periods by cutting off exogenous substrate supply.
- Assessed microbial activity using 16S rDNA and 16S rRNA/16S rDNA ratios.
- Measured specific methanization activity and delay time for gas production (DTGS).
Main Results:
- Substrate cutoff induced dormancy, with significant reduction in methanization microorganisms (bacteria and archaea).
- Resuming substrate supply restored vegetative state and specific methanization activity, but prolonged DTGS.
- Dormancy reduced extracellular polymeric substances (EPS) consumption, stabilizing sludge structure and community.
Conclusions:
- Microbial dormancy is key to apparent functional fluctuations and intrinsic stability of AnGS under starvation.
- Dormancy mechanisms protect the methanization community and sludge structure during starvation.
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