Table 3. 16S Operational Taxonomic Units (OTUs) affiliated to Hyphomicrobium spp. and Methylophaga spp. in the OB and the IO biofilm cultures.

		Number of OTUs	Number reads		Proportion of reads %
			OB	IO	OB	IO
Sequence identity with H. nitrativorans
Cluster 1	95–100%	12	147,209	26,239	92.3	97.8
Cluster 2	91–97%	5	10,779	530	6.8	2.0
Cluster 3	89–92%	3	1,537	51	0.96	0.19
Sequence identity with M. nitratireducenticrescens
Cluster 1	94–100%	18	11,809	136,197	96.4	99.7
Cluster 2	92.9–93.6%	3	321	284	2.62	0.21
Cluster 3	93.4–94.1%	3	115	65	0.94	0.05

Notes.

Cluster classification is based on phylogenic analyses of the 16S rRNA gene sequences affiliated to H. nitrativorans and M. nitratireducenticrescens (see Tables S1 and S2, and Figs. S2A and S2B).