In total, 10,302 16S rRNA gene sequences were produced
from six experimental samples. Analysis with RDP classifier
revealed nine phyla, 16 classes, 26 orders, 46 families, and
47 genera of known bacteria in the samples. The number of
biological classification groups in the six samples are presented
in Table 1. The difference in microbial community
composition between samples is shown in Fig. 2. Two main
clusters correspond to the presence and absence of PBDEs
(Fig 2). The first cluster is composed of samples A1 and A2
for anaerobic sediment without PBDEs. The second cluster
is composed of samples A3eA6 for anaerobic degradation
of BDE-28 and BDE-209. This cluster is further divided into
two subclusters that correspond to the presence and
absence of zero-valent iron. Thus, the bacterial composition
distinguished between anaerobic degradation of BDE-
28 and BDE-209 and anaerobic sediment without PBDEs