## 3 Results and Discussion
### Phylogenetics of MAGs and Their Abundance in the PSD and AnMBR  
A large fraction of the reads were assembled in contigs \(\geq\)1000 bp (114,558 contigs including 396,835,232 bp), yielding an N50 (defined as the minimum contig length needed to cover 50% of the total lengths of cotnigs) of 4676 with a max contig length of 323,550 and a mean size of contigs of 2139 bp. To further examine the metabolic properties of the dominant species in the PSD and AnMBR, metagenomic binning based on composition and differential coverage of contigs was performed to reconstruct the MAGs of the species that dominated these processes. Thereby, 21 MAGs (16 and 7 affiliated with _Bacteria_ and _Archaea_, respectively) were observed and assigned to 15 categories, with an average completeness of 93.0% and contamination of 2.9% (Table 2). The genome sizes of the MAGs ranged from 1,551,831 bp to 5,015,715 bp, with an average of 2,650,305 bp, and the number of contigs in each MAG ranged from 142 to 629, with an average N50 size of 12,914 and mean contig length of 8695 bp (Table 2). \begin{table}
\begin{tabular}{c c c c c c c c c c c c c} \hline \hline \multirow{2}{*}{**ID**} & \multicolumn{2}{c}{**Classification b**} & \multirow{2}{*}{**NS0 c**c**} & \multicolumn{2}{c}{**No**} & \multicolumn{2}{c}{**Total Length of**} & \multicolumn{2}{c}{**Average Config**} & \multicolumn{2}{c}{**Max Config**} & \multicolumn{2}{c}{**GC**} & \multicolumn{2}{c}{**No of**} & \multicolumn{2}{c}{**Comple**} & \multicolumn{2}{c}{**Contan**} & \multicolumn{2}{c}{**Sequencing Depth ***} \\  & & & **Conigs** & **Conigs** & **Length** & **Length** & **Length** & **Length** & **(px)** & **ORs** & **(px)** & **(px)** & **(px)** & **(px)** & **(px)** & **(px)** & **(px)** & **(px)** & **(px)** & **(px)** & **(px)** & **(px)** & **(px)** & **(px)** & **(px)** & **(px)** & **(px)** & **(px)** \\ \hline MAG100 & _Succiianness_ sp. & 16,425 & 223 & 2,345,215 & 10,517 & 63,091 & 36.82 & 2223 & 97.76 & 28.7 & 30.4 & 8.39 & \\ MAG11 & _Mechanmircirches_ archaeon & 70,075 & 436 & 2,646,698 & 6700 & 25,219 & 42.08 & 2833 & 79.45 & 5.23 & 3.74 & 2.48 & \\ MAG13 & _Mechanmirches_ archaeon & 2,305 & 24 & 1,690,900 & 9166 & 45,173 & 42.15 & 2081 & 83.94 & 0.84 & 38.34 & 6.63 & \\ MAG14 & _Mechanmirches_ archaeon & 2,3088 & 142 & 2,396,620 & 16,173 & 116,341 & 88.15 & 261 & 93.17 & 2.67 & 6.53 & 0.20 & \\ MAG14 & _FawA detailed overview of the taxonomic classification of the MAGs is provided in Figure 3 and Table 2, in which a taxonomic classification with high confidence was possible to the species level for all the MAGs. In summary, 7 MAGs were attributed to the phylum _Euryarchaeota_, including 4 for _Methanobacterium_ sp. (MAG13, MAG14, MAG16, and MAG19), 1 for _Methanomassilicocales archaea_ (MAG215), 1 for _Methanosaeta concilli_ (MAG220), and 1 for _Methanomicrobiales_ archaea (MAG11). The second most abundant taxonomic MAGs classification was _Bacteroidales_ bacterium, with 4 observed MAGs (MAG158, MAG217, MAG228, and MAG42). Furthermore, _Synergistaceae_ bacterium with only 1 observed MAG (MAG200) belonging to the family _Firmicutes_ was recruited from the metagenomic dataset. The remaining MAGs were mainly affiliated with the _Aminophilus circumscriptus_ (MAG74), _Desulfovibrio desulfuricans_ (MAG68), _Fusobacteriaceae_ bacterium (MAG142), _Nitrospirae_ bacterium (MAG161), _Prolixibacteraceae_ bacterium (MAG59), _Succinispia mobilis_ (MAG159), and _Sulfurovum_ sp. (MAG55) (Figure 3). The relationships between the MAGs and their closest species with complete genome sequences are shown in Figure 3. Most of the recruited MAGs belonged to _Methanogenic_ archaea. MAG13, MAG14, MAG16, and MAG19 were most familiar with the genome of _Methanobacterium_ sp. SMA-27, for which no information regarding its origin is publicly available. The sequences of MAG215 had high similarity with _Methanomassilicocales_ archaeon RumEn M2, which has been reported to be a trimethylamine-utilizing archaea [55].