title: Anaerobic degradation of benzene by enriched consortia with humic acids as terminal electron acceptors.
abstract: The anaerobic degradation of benzene coupled to the reduction of humic acids (HA) was demonstrated in two enriched consortia. Both inocula were able to oxidize benzene under strict anaerobic conditions when the humic model compound, anthraquinone-2,6-disulfonate (AQDS), was supplied as terminal electron acceptor. An enrichment culture originated from a contaminated soil was also able to oxidize benzene linked to the reduction of highly purified soil humic acids (HPSHA). In HPSHA-amended cultures, 9.3 μM of benzene were degraded, which corresponds to 279 ± 27 micro-electron equivalents (μEq)L(-1), linked to the reduction of 619 ± 81 μEq L(-1) of HPSHA. Neither anaerobic benzene oxidation nor reduction of HPSHA occurred in sterilized controls. Anaerobic benzene oxidation did not occur in soil incubations lacking HPSHA. Furthermore, negligible reduction of HPSHA occurred in the absence of benzene. The enrichment culture derived from this soil was dominated by two γ-Proteobacteria phylotypes. A benzene-degrading AQDS-reducing enrichment originated from a sediment sample showed the prevalence of different species from classes β-, δ- and γ-Proteobacteria. The present study provides clear quantitative demonstration of anaerobic degradation of benzene coupled to the reduction of HA.
authors: División de Ciencias Ambientales, Instituto Potosino de Investigación Científica y Tecnológica (IPICyT), Camino a la Presa San José 2055, Col. Lomas 4ª. Sección, San Luis Potosí, SLP, 78216 Mexico. fjcervantes@ipicyt.edu.mx
authors: Francisco J
authors: FJ
authors: Cervantes
authors: Ana Rosa
authors: AR
authors: Mancilla
authors: E Emilia
authors: EE
authors: Ríos-del Toro
authors: Angel G
authors: AG
authors: Alpuche-Solís
authors: Lilia
authors: L
authors: Montoya-Lorenzana
mesh_terms: D000693:Anaerobiosis; D001419:Bacteria / Q000145:classification / Q000235:genetics / Q000378:metabolism; D001483:Base Sequence; D001554:Benzene / Q000378:metabolism*; D001673:Biodegradation, Environmental; D002849:Chromatography, Gas; D003001:Cloning, Molecular; D017931:DNA Primers; D004583:Electrons; D006812:Humic Substances; D010802:Phylogeny; D016133:Polymerase Chain Reaction; D012336:RNA, Ribosomal, 16S / Q000235:genetics
chemical_list: D017931:DNA Primers; D006812:Humic Substances; D012336:RNA, Ribosomal, 16S; D001554:Benzene