Abstract
Anaerobic digestion (AD) is globally applied for bioenergy production. Although its widespread application, improved understanding of the underlying microbial ecology is needed to provide solutions for optimised process performance. In this study, we investigated the impact of immigration on the microbial community and conducted detailed investigations of bacteria from the hitherto undescribed phylum Hyd24-12, which’s role in AD has been overlooked so far.
A total of 32 AD reactors at 18 Danish full-scale wastewater treatment plants were sampled during five years of operation. The bacterial and archaeal community were analysed separately using 16S rRNA gene amplicon sequencing in all 300+ samples. In addition, the microbial composition in the feed were analysed to investigate the effect of immigrating microbes. Full-scale AD reactors applying thermal hydrolysis based pre-treatment served as controls without influent microbes.
The immigrating microorganisms had a notable influence on community structure. Comparing the abundance in the feed and AD reactors, we were able to classify 10 of the 20 most abundant genera as heavily influenced by immigration and potentially inactive. Hence, not taking immigration into account, would highly bias the conclusions. One of the most abundant non-immigrating bacteria belonged to candidate phylum Hyd24-12. Using differential coverage binning of multiple AD metagenomes, we retrieved the first genome of Hyd24-12. The genome allowed for detailed metabolic reconstruction, which revealed a strictly fermentative metabolism. In addition, FISH probes were designed for visualization and further in-situ studies to elucidate the microbial ecology of this, so far, overlooked group of bacteria in AD.
A total of 32 AD reactors at 18 Danish full-scale wastewater treatment plants were sampled during five years of operation. The bacterial and archaeal community were analysed separately using 16S rRNA gene amplicon sequencing in all 300+ samples. In addition, the microbial composition in the feed were analysed to investigate the effect of immigrating microbes. Full-scale AD reactors applying thermal hydrolysis based pre-treatment served as controls without influent microbes.
The immigrating microorganisms had a notable influence on community structure. Comparing the abundance in the feed and AD reactors, we were able to classify 10 of the 20 most abundant genera as heavily influenced by immigration and potentially inactive. Hence, not taking immigration into account, would highly bias the conclusions. One of the most abundant non-immigrating bacteria belonged to candidate phylum Hyd24-12. Using differential coverage binning of multiple AD metagenomes, we retrieved the first genome of Hyd24-12. The genome allowed for detailed metabolic reconstruction, which revealed a strictly fermentative metabolism. In addition, FISH probes were designed for visualization and further in-situ studies to elucidate the microbial ecology of this, so far, overlooked group of bacteria in AD.
| Original language | English |
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| Publication date | 2016 |
| Publication status | Published - 2016 |
| Event | 16th International Symposium on Microbial Ecology - Palais des Congres de Montreal, Montreal, Canada Duration: 21 Aug 2016 → 26 Aug 2016 http://www.isme-microbes.org/isme16 |
Conference
| Conference | 16th International Symposium on Microbial Ecology |
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| Location | Palais des Congres de Montreal |
| Country/Territory | Canada |
| City | Montreal |
| Period | 21/08/2016 → 26/08/2016 |
| Internet address |