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Methanogenic pathway and community structure in a thermophilic anaerobic digestion process of organic solid waste

Paper ID Volume ID Publish Year Pages File Format Full-Text
21120 43207 2011 6 PDF Available
Title
Methanogenic pathway and community structure in a thermophilic anaerobic digestion process of organic solid waste
Abstract

The methanogenic pathway and microbial community in a thermophilic anaerobic digestion process of organic solid waste were investigated in a continuous-flow stirred-tank reactor using artificial garbage slurry as a feedstock. The decomposition pathway of acetate, a significant precursor of CH4 and a key intermediate metabolite in the anaerobic digestion process, was analyzed by using stable isotopes. A tracer experiment using 13C-labeled acetate revealed that approximately 80% of the acetate was decomposed via a non-aceticlastic oxidative pathway, whereas the remainder was converted to methane via an aceticlastic pathway. Archaeal 16S rRNA analyses demonstrated that the hydrogenotrophic methanogens Methanoculleus spp. accounted for > 90% of detected methanogens, and the aceticlastic methanogens Methanosarcina spp. were the minor constituents. The clone library targeting bacterial 16S rRNA indicated the predominance of the novel Thermotogales bacterium (relative abundance: ~ 53%), which is related to anaerobic acetate oxidizer Thermotoga lettingae TMO, although the sequence similarity was low. Uncultured bacteria that phylogenetically belong to municipal solid waste cluster I were also predominant in the microflora (~ 30%). These results imply that the microbial community in the thermophilic degrading process of organic solid waste consists exclusively of unidentified bacteria, which efficiently remove acetate through a non-aceticlastic oxidative pathway.

Keywords
Thermophilic methanogenic bioreactor; Organic solid waste; Methanogenic pathway; Microbial community structure
First Page Preview
Methanogenic pathway and community structure in a thermophilic anaerobic digestion process of organic solid waste
Publisher
Database: Elsevier - ScienceDirect
Journal: Journal of Bioscience and Bioengineering - Volume 111, Issue 1, January 2011, Pages 41–46
Authors
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Subjects
Physical Sciences and Engineering Chemical Engineering Bioengineering