title: Complete perchlorate reduction using methane as the sole electron donor and carbon source.
abstract: Using a CH4-based membrane biofilm reactor (MBfR), we studied perchlorate (ClO4(-)) reduction by a biofilm performing anaerobic methane oxidation coupled to denitrification (ANMO-D). We focused on the effects of nitrate (NO3(-)) and nitrite (NO2(-)) surface loadings on ClO4(-) reduction and on the biofilm community's mechanism for ClO4(-) reduction. The ANMO-D biofilm reduced up to 5 mg/L of ClO4(-) to a nondetectable level using CH4 as the only electron donor and carbon source when CH4 delivery was not limiting; NO3(-) was completely reduced as well when its surface loading was ≤ 0.32 g N/m(2)-d. When CH4 delivery was limiting, NO3(-) inhibited ClO4(-) reduction by competing for the scarce electron donor. NO2(-) inhibited ClO4(-) reduction when its surface loading was ≥ 0.10 g N/m(2)-d, probably because of cellular toxicity. Although Archaea were present through all stages, Bacteria dominated the ClO4(-)-reducing ANMO-D biofilm, and gene copies of the particulate methane mono-oxygenase (pMMO) correlated to the increase of respiratory gene copies. These pieces of evidence support that ClO4(-) reduction by the MBfR biofilm involved chlorite (ClO2(-)) dismutation to generate the O2 needed as a cosubstrate for the mono-oxygenation of CH4.
authors.affiliation: MOE Key Lab of Environmental Remediation and Ecosystem Health, College of Environmental and Resource Science, Zhejiang University , Hangzhou, China.
authors.forename: Yi-Hao
authors.initials: YH
authors.lastname: Luo
authors.forename: Ran
authors.initials: R
authors.lastname: Chen
authors.forename: Li-Lian
authors.initials: LL
authors.lastname: Wen
authors.forename: Fan
authors.initials: F
authors.lastname: Meng
authors.forename: Yin
authors.initials: Y
authors.lastname: Zhang
authors.forename: Chun-Yu
authors.initials: CY
authors.lastname: Lai
authors.forename: Bruce E
authors.initials: BE
authors.lastname: Rittmann
authors.forename: He-Ping
authors.initials: HP
authors.lastname: Zhao
authors.forename: Ping
authors.initials: P
authors.lastname: Zheng
mesh_terms: D000693:Anaerobiosis; D001105:Archaea / Q000235:genetics / Q000378:metabolism; D001419:Bacteria / Q000235:genetics / Q000378:metabolism; D018441:Biofilms; D019149:Bioreactors / Q000382:microbiology; D002244:Carbon / Q000737:chemistry; D058440:Denitrification; D004583:Electrons; D005786:Gene Expression Regulation; D008567:Membranes, Artificial; D008697:Methane / Q000737:chemistry* / Q000378:metabolism; D059013:Microbial Consortia / Q000502:physiology*; D009566:Nitrates / Q000378:metabolism; D010084:Oxidation-Reduction; D010472:Perchlorates / Q000737:chemistry* / Q000378:metabolism; D010539:Permeability; D012336:RNA, Ribosomal, 16S
chemical_list: D008567:Membranes, Artificial; D009566:Nitrates; D010472:Perchlorates; D012336:RNA, Ribosomal, 16S; D002244:Carbon; D008697:Methane; C494474:perchlorate