| description |
Temporal microbial succession was investigated in relation to the performance in a methane biofilter. A laboratory-scale biofilter packed with perlite was operated for 108 days, without deliberately washing out excess biomass. Methane removal performance was stable at a removal efficiency (RE) of 61.3% over the period although temporally deteriorated for a 45-56 day period. Ribosomal tag pyrosequencing showed that bacterial communities of days 14 and 28 (an earlier period) were distinctly discriminated from those of days 68 and 108 (a later period), but community structure did not vary after 14 days. Rhodobacter, Hydrogenophaga and Methylomonas (methanotroph, M) were dominant in the earlier period, but minor in the later period. In contrast, Methylocaldum (M) and Methylococcus (M) were abundant only in the later period. Methanotrophic proportion gradually increased from 15 to 41% with time in the community. Type II methanotrophs comprised up >20% in the earlier period but rarely survived in the later period. The substantial microbial succession might be responsible for the temporal performance deterioration in the system. It was found that accumulation of nonviable substances strongly coincided with the community change (R2>0.97), which suggested that nonviable biomass accumulation is an intrinsic factor driving microbial community change in a methane biofilter. In conclusion, the perilte biofilter for methane mitigation was functionally rigid against the temporal succession of total bacterial and methanotrophic communities. |