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- ItemCharacterization of Bathyarchaeota genomes assembled from metagenomes of biofilms residing in mesophilic and thermophilic biogas reactors(London : BioMed Central Ltd., 2018) Maus, I.; Rumming, M.; Bergmann, I.; Heeg, K.; Pohl, M.; Nettmann, E.; Jaenicke, S.; Blom, J.; Pühler, A.; Schlüter, A.; Sczyrba, A.; Klocke, M.Background: Previous studies on the Miscellaneous Crenarchaeota Group, recently assigned to the novel archaeal phylum Bathyarchaeota, reported on the dominance of these Archaea within the anaerobic carbohydrate cycle performed by the deep marine biosphere. For the first time, members of this phylum were identified also in mesophilic and thermophilic biogas-forming biofilms and characterized in detail. Results: Metagenome shotgun libraries of biofilm microbiomes were sequenced using the Illumina MiSeq system. Taxonomic classification revealed that between 0.1 and 2% of all classified sequences were assigned to Bathyarchaeota. Individual metagenome assemblies followed by genome binning resulted in the reconstruction of five metagenome-assembled genomes (MAGs) of Bathyarchaeota. MAGs were estimated to be 65-92% complete, ranging in their genome sizes from 1.1 to 2.0 Mb. Phylogenetic classification based on core gene sets confirmed their placement within the phylum Bathyarchaeota clustering as a separate group diverging from most of the recently known Bathyarchaeota clusters. The genetic repertoire of these MAGs indicated an energy metabolism based on carbohydrate and amino acid fermentation featuring the potential for extracellular hydrolysis of cellulose, cellobiose as well as proteins. In addition, corresponding transporter systems were identified. Furthermore, genes encoding enzymes for the utilization of carbon monoxide and/or carbon dioxide via the Wood-Ljungdahl pathway were detected. Conclusions: For the members of Bathyarchaeota detected in the biofilm microbiomes, a hydrolytic lifestyle is proposed. This is the first study indicating that Bathyarchaeota members contribute presumably to hydrolysis and subsequent fermentation of organic substrates within biotechnological biogas production processes.
- ItemGenomics and prevalence of bacterial and archaeal isolates from biogas-producing microbiomes(London : BioMed Central, 2017-11-13) Maus, Irena; Bremges, Andreas; Stolze, Yvonne; Hahnke, Sarah; Cibis, Katharina G.; Koeck, Daniela E.; Kim, Yong S.; Kreubel, Jana; Hassa, Julia; Wibberg, Daniel; Weimann, Aaron; Off, Sandra; Stantscheff, Robbin; Zverlov, Vladimir V.; Schwarz, Wolfgang H.; König, Helmut; Liebl, Wolfgang; Scherer, Paul; McHardy, Alice C.; Sczyrba, Alexander; Klocke, Michael; Pühler, Alfred; Schlüter, AndreasBackground: To elucidate biogas microbial communities and processes, the application of high-throughput DNA analysis approaches is becoming increasingly important. Unfortunately, generated data can only partialy be interpreted rudimentary since databases lack reference sequences. Results: Novel cellulolytic, hydrolytic, and acidogenic/acetogenic Bacteria as well as methanogenic Archaea originating from different anaerobic digestion communities were analyzed on the genomic level to assess their role in biomass decomposition and biogas production. Some of the analyzed bacterial strains were recently described as new species and even genera, namely Herbinix hemicellulosilytica T3/55T, Herbinix luporum SD1DT, Clostridium bornimense M2/40T, Proteiniphilum saccharofermentans M3/6T, Fermentimonas caenicola ING2-E5BT, and Petrimonas mucosa ING2-E5AT. High-throughput genome sequencing of 22 anaerobic digestion isolates enabled functional genome interpretation, metabolic reconstruction, and prediction of microbial traits regarding their abilities to utilize complex bio-polymers and to perform specific fermentation pathways. To determine the prevalence of the isolates included in this study in different biogas systems, corresponding metagenome fragment mappings were done. Methanoculleus bourgensis was found to be abundant in three mesophilic biogas plants studied and slightly less abundant in a thermophilic biogas plant, whereas Defluviitoga tunisiensis was only prominent in the thermophilic system. Moreover, several of the analyzed species were clearly detectable in the mesophilic biogas plants, but appeared to be only moderately abundant. Among the species for which genome sequence information was publicly available prior to this study, only the species Amphibacillus xylanus, Clostridium clariflavum, and Lactobacillus acidophilus are of importance for the biogas microbiomes analyzed, but did not reach the level of abundance as determined for M. bourgensis and D. tunisiensis. Conclusions: Isolation of key anaerobic digestion microorganisms and their functional interpretation was achieved by application of elaborated cultivation techniques and subsequent genome analyses. New isolates and their genome information extend the repository covering anaerobic digestion community members. © 2017 The Author(s).
- ItemProteiniphilum saccharofermentans str. M3/6T isolated from a laboratory biogas reactor is versatile in polysaccharide and oligopeptide utilization as deduced from genome-based metabolic reconstructions(Amsterdam [u.a.] : Elsevier, 2018) Tomazetto, Geizecler; Hahnke, Sarah; Wibberg, Daniel; Pühler, Alfred; Klocke, Michael; Schlüter, AndreasProteiniphilum saccharofermentans str. M3/6T is a recently described species within the family Porphyromonadaceae (phylum Bacteroidetes), which was isolated from a mesophilic laboratory-scale biogas reactor. The genome of the strain was completely sequenced and manually annotated to reconstruct its metabolic potential regarding biomass degradation and fermentation pathways. The P. saccharofermentans str. M3/6T genome consists of a 4,414,963 bp chromosome featuring an average GC-content of 43.63%. Genome analyses revealed that the strain possesses 3396 protein-coding sequences. Among them are 158 genes assigned to the carbohydrate-active-enzyme families as defined by the CAZy database, including 116 genes encoding glycosyl hydrolases (GHs) involved in pectin, arabinogalactan, hemicellulose (arabinan, xylan, mannan, β-glucans), starch, fructan and chitin degradation. The strain also features several transporter genes, some of which are located in polysaccharide utilization loci (PUL). PUL gene products are involved in glycan binding, transport and utilization at the cell surface. In the genome of strain M3/6T, 64 PUL are present and most of them in association with genes encoding carbohydrate-active enzymes. Accordingly, the strain was predicted to metabolize several sugars yielding carbon dioxide, hydrogen, acetate, formate, propionate and isovalerate as end-products of the fermentation process. Moreover, P. saccharofermentans str. M3/6T encodes extracellular and intracellular proteases and transporters predicted to be involved in protein and oligopeptide degradation. Comparative analyses between P. saccharofermentans str. M3/6T and its closest described relative P. acetatigenes str. DSM 18083T indicate that both strains share a similar metabolism regarding decomposition of complex carbohydrates and fermentation of sugars. © 2018 The Authors