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New insights into the r/K selection theory achieved in methanogenic systems through continuous-flow and sequencing batch operational modes.
- Source :
-
The Science of the total environment [Sci Total Environ] 2022 Feb 10; Vol. 807 (Pt 1), pp. 150732. Date of Electronic Publication: 2021 Oct 02. - Publication Year :
- 2022
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Abstract
- Anaerobic digestion is achieved through cooperation among various types of microorganisms, and the regulation of microbial communities is key to achieving stable system operation. In this study, the r/K selection theory was adopted to examine the system performance and microbial characteristics in anaerobic reactors with different operating modes (continuous-flow reactors, CFRs; sequencing batch reactors, SBRs) and sludge retention times (25 and 10 days). Four lab-scale reactors (CFR <subscript>25d</subscript> , CFR <subscript>10d</subscript> , SBR <subscript>25d</subscript> , and SBR <subscript>10d</subscript> ) were operated. In the cycle reaction, CFR <subscript>25d</subscript> achieved the highest methane yield (678.0 mL/L) and methane production rate (140.8 mL/(L·h)); while those in CFR <subscript>10d</subscript> were the lowest, which could have been due to an accumulation of volatile fatty acids. CFR could wash out r-strategists efficiently, such as Methanosarcina. CFR <subscript>25d</subscript> and CFR <subscript>10d</subscript> significantly enriched the K-strategist Geobacter, with the relative abundances of 34.0% and 72.6%, respectively. In addition, the hydrogenotrophic methanogens of Methanolinea and Methanospirillum (K-strategists) dominated in CFR <subscript>25d</subscript> and CFR <subscript>10d</subscript> . Methanobacterium adapted to the diverse operational conditions, but the slow grower Methanosaeta only accounted for 0.9% in CFR <subscript>10d</subscript> . Failure to enrich propionate oxidizers resulted in a functional absence of propionate degradation in the CFRs.<br />Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper.<br /> (Copyright © 2021 The Authors. Published by Elsevier B.V. All rights reserved.)
- Subjects :
- Anaerobiosis
Methanosarcina
Sewage
Bioreactors
Methane
Subjects
Details
- Language :
- English
- ISSN :
- 1879-1026
- Volume :
- 807
- Issue :
- Pt 1
- Database :
- MEDLINE
- Journal :
- The Science of the total environment
- Publication Type :
- Academic Journal
- Accession number :
- 34606861
- Full Text :
- https://doi.org/10.1016/j.scitotenv.2021.150732