title: Long-term anaerobic mineralization of pentachlorophenol in a continuous-flow system using only lactate as an external nutrient.
abstract: A simple anaerobic upflow column system (15 cm long, 5 cm inner diameter) for complete pentachlorophenol (PCP) mineralization has been established using a microbial consortium requiring only lactate as the external nutrient. With lactate as an electron donor, PCP was dechlorinated to 3-chlorophenol (3-CP) and phenol. The degradation of 3-CP and phenol proceeded without an external electron acceptor, indicating fermentative or syntrophic characteristics. A tracer experiment using (14)C-U-ring-labeled PCP confirmed the conversion of PCP into CO(2) (54.1%), CH(4) (48.1%), and biomass (0.6%). The nitrogen required for degradation was supplied by N(2)-fixation, evidenced from the nitrogen balance and an acetylene reduction assay. A 16S rRNA gene library analysis showed that bottom of the upflow column harbored the potential dechlorinators, Dehalobacter and Desulfitobacterium, and the phenol/3-CP fermentative or syntrophic degraders, Cryptanaerobacter and Syntrophus. The nitrogen-fixing facultative anaerobes, Rhizobiales, were detected in the top of the upflow column, with other possible nitrogen-fixers at both bottom and top of the upflow column. The mineralization rate reached 1.96 μmoles L(-1) d(-1) for 50 μM of the initial PCP concentration: one of the highest efficiencies reported. This compact anaerobic mineralization system requiring no external supply of an electron acceptor would be useful for the remediation of chlorinated aromatic compounds under anaerobic conditions.
authors.affiliation: EcoTopia Science Institute, Nagoya University, Chikusa, Nagoya 464-8603 Japan.
authors.forename: Zhiling
authors.initials: Z
authors.lastname: Li
authors.forename: Yasushi
authors.initials: Y
authors.lastname: Inoue
authors.forename: Daisuke
authors.initials: D
authors.lastname: Suzuki
authors.forename: Lizhen
authors.initials: L
authors.lastname: Ye
authors.forename: Arata
authors.initials: A
authors.lastname: Katayama
mesh_terms: D000693:Anaerobiosis / Q000187:drug effects; D001419:Bacteria / Q000187:drug effects / Q000378:metabolism; D001483:Base Sequence; D061249:Batch Cell Culture Techniques; D001673:Biodegradation, Environmental / Q000187:drug effects; D018533:Biomass; D019149:Bioreactors / Q000382:microbiology; D002244:Carbon / Q000032:analysis; D002247:Carbon Isotopes; D002733:Chlorophenols / Q000378:metabolism; D052918:Environmental Restoration and Remediation / Q000379:methods*; D019344:Lactic Acid / Q000494:pharmacology*; D008903:Minerals / Q000378:metabolism*; D008969:Molecular Sequence Data; D009584:Nitrogen / Q000032:analysis; D010416:Pentachlorophenol / Q000378:metabolism*; D010802:Phylogeny; D016062:Porosity; D012336:RNA, Ribosomal, 16S / Q000235:genetics; D012212:Rheology / Q000187:drug effects; D013997:Time Factors; D014865:Waste Disposal, Fluid
chemical_list: D002247:Carbon Isotopes; D002733:Chlorophenols; D008903:Minerals; D012336:RNA, Ribosomal, 16S; D019344:Lactic Acid; D002244:Carbon; D010416:Pentachlorophenol; D009584:Nitrogen; C030682:3-chlorophenol