How the acetate and propionate accumulation impact anaerobic syntrophy during methane formation is not well understood. To investigate such effect, continuous acetate (35 g/L), propionate (11.25 g/L) and bicarbonate (30 g/L) supplementation were used during mesophilic anaerobic digestion. The high throughput sequencing (16S rRNA and mcrA), Real-Time quantitative PCR, and stable carbon isotope fingerprinting were applied to investigate the structure and activity of microbial community members. The results demonstrated that the abundance of syntrophic acetate oxidizing bacteria exhibited a gradual decrease coupled with heavier stable carbon isotopic signature of methane (δ 13CH4) in the three reagents impacted reactors. The increased acetate and propionate concentrations exerted negative influence on biogas production but the relatively stable hydrogenotrophic methanogens together with syntrophic acetate/propionate oxidizing bacteria kept the stable methane formation facing acetate and propionate accumulation. The functional genes copy number of the hydrogenotrophic Methanocellaceae and Methanomicrobiaceae correlated significantly with δ 13CH4 (R2 > 0.74), but only the abundance of Methanocellaceae fitted well with δ 13CH4 (p < 0.05). The δ 13CH4 signatures can predict methanogenesis, as it directly reflects the main methanogenic pathway; yet, further investigation of isotope fractionation in acetate/propionate coupled with δ 13CH4 is needed. Collectively, these results provide deep insight into anaerobic syntrophy and reveal changes of synergistic relationships, both of which may contribute to the stability of biogas reactors.
- MeSH
- acetáty MeSH
- anaerobióza MeSH
- bioreaktory * MeSH
- methan MeSH
- propionáty * MeSH
- RNA ribozomální 16S genetika MeSH
- Publikační typ
- časopisecké články MeSH
Temperature regulations (mesophilic/thermophilic) and digesting modes (mono-/co-digestion) play key roles in the biomethane potential of anaerobic digestion, but limited research focus on the synergetic effects on microbial interconnections of the biomethane process. In this study, the pineapple and maize residues under different operations were monitored by batch biogas assays and 16S high-throughput sequencing to explore: 1) biomethane potential regarding different operations, 2) microbial communities in different treated reactors, and 3) significant factors determine microbial distribution. Results showed that the co-digestion had higher methanogenic abundance and biomethane production (~3300 mLn) versus mono-digestion under mesophilic condition. To the thermophilic condition, the co-digestion had less methanogenic abundance but more biomethane production (~5000 mLn). Statistical evidence uncovered that the Clostridiaceae and Thermoanaerobacteraceae dominated pathways linked closely with methanogenesis which may contribute the more biomethane production in the thermophilic condition. This study demonstrated the temperature regulations drove rare taxa as major contributors for biomethane production.
- MeSH
- anaerobióza MeSH
- biopaliva MeSH
- bioreaktory * MeSH
- Euryarchaeota * MeSH
- methan MeSH
- teplota MeSH
- Publikační typ
- časopisecké články MeSH
Process fluctuation caused by temperature modification of anaerobic digestion is routinely monitored via operational parameters, such as pH and gas production, but these parameters are lagging on microbial community performance. In this study, 13C isotope fractionation in CH4 and CO2 of biogas together with microbial community dynamics were applied to evaluate process stability in response to temperature increment. Results showed that the weakening correlated links between Firmicutes affiliated families and Methanomicrobiaceae were found regarding temperature increase. In contrast, Methanosarcinaceae and Methanobacteriaceae strengthened their links with multiple bacterial groups. This suggests that the 13C isotope fractionation in CH4 can predict the collapse of certain microbial interconnections and process instability, the new reinforced microbial links directly reflect the microbial community redundancy for maintaining function of syntrophic populations.
- MeSH
- anaerobióza MeSH
- Bacteria MeSH
- bioreaktory * MeSH
- Euryarchaeota * MeSH
- methan MeSH
- teplota MeSH
- Publikační typ
- časopisecké články MeSH
