title: Analysis of structure, function, and activity of a benzene-degrading microbial community.
abstract: We identified phylotypes performing distinct functions related to benzene degradation in complex microbial biofilms from an aerated treatment pond containing coconut textile. RNA- and protein-stable isotope probing (SIP) and compound-specific stable isotope analysis were applied to delineate bacteria and predominant pathways involved in the degradation of benzene. In laboratory microcosms, benzene was degraded at rates of ≥ 11 μM per day and per gram coconut textile under oxic conditions. Carbon isotope fractionation with isotopic enrichment factors (ε) of -0.6 to -1‰ and no significant hydrogen isotope fractionation indicated a dihydroxylation reaction for the initial ring attack. The incubation with [(13)C₆]-benzene led to (13)CO₂ formation accompanied by (13)C-labeling of RNA and proteins of the active biomass. Phylogenetic analysis of the (13)C-labeled RNA revealed that phylotypes related to Zoogloea, Ferribacterium, Aquabacterium, and Hydrogenophaga within the Betaproteobacteria predominantly assimilated carbon from benzene. Although the phylogenetic classification of identified (13)C-labeled proteins was biased by the incomplete metagenome information of public databases, it matched with RNA-SIP results at genus level. The detection of (13)C-labeled proteins related to toluene dioxygenase and catechol 2,3-dioxygenase suggests benzene degradation by a dihydroxylation pathway with subsequent meta-cleavage of formed catechol.
authors: Department of Isotope Biogeochemistry, UFZ - Helmholtz Centre for Environmental Research, Leipzig, Germany.
authors: Sven
authors: S
authors: Jechalke
authors: Alessandro G
authors: AG
authors: Franchini
authors: Felipe
authors: F
authors: Bastida
authors: Petra
authors: P
authors: Bombach
authors: Mónica
authors: M
authors: Rosell
authors: Jana
authors: J
authors: Seifert
authors: Martin
authors: M
authors: von Bergen
authors: Carsten
authors: C
authors: Vogt
authors: Hans H
authors: HH
authors: Richnow
mesh_terms: D019843:Archaeal Proteins / Q000032:analysis / Q000737:chemistry; D001419:Bacteria / Q000145:classification / Q000235:genetics / Q000378:metabolism*; D001426:Bacterial Proteins / Q000032:analysis / Q000737:chemistry; D001554:Benzene / Q000378:metabolism*; D001673:Biodegradation, Environmental; D018441:Biofilms; D002247:Carbon Isotopes; D050557:Catechol 2,3-Dioxygenase / Q000032:analysis; D020387:Food Chain; D006859:Hydrogen; D010802:Phylogeny
chemical_list: D019843:Archaeal Proteins; D001426:Bacterial Proteins; D002247:Carbon Isotopes; D006859:Hydrogen; D050557:Catechol 2,3-Dioxygenase; D001554:Benzene