A specially designed CH 4 -based membrane biofilm batch reactor (MBBR) was applied to investigate anaerobic methane oxidation coupled to perchlorate reduction (AnMO-PR). The 0.21 mM ClO 4 − added in the first stage of operation was completely reduced in 28 days, 0.40 mM ClO 4 − was reduced within 23 days in stage 2, and 0.56 mM of ClO 4 − was reduced within 30 days in stage 3. Although some chlorate (ClO 3 − ) accumulated, the recovery of Cl − was over 92%. Illumina sequencing of the 16S rRNA gene documented that the bacterial community was mainly composed by perchlorate-reducing bacteria (PRB), methanotrophic bacteria, and archaea. Real-time quantitative PCR showed the archaeal 16S rRNA and mcrA genes increased as more ClO 4 − was reduced, and the predominant archaea belonged to Methanosarcina mazei, which is related to ANME-3, an archaeon able to perform reverse methanogenesis. Several pieces of evidence support that ClO 4 − reduction by the MBBR biofilm occurred via a synergism between Methanosarcina and PRB: Methanosarcina oxidized methane through reverse methanogesis and provided electron donor for PRB to reduce ClO 4 − . Because methanotrophs were present, we cannot rule out that they also were involved in AnMO-PR if they received O 2 generated by disproportionation of ClO 2 − from the PRB.
- Membrane-biofilm batch reactor
- Methane oxidation
- Perchlorate reduction
ASJC Scopus subject areas
- Environmental Engineering
- Environmental Chemistry
- Waste Management and Disposal