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.
Original language | English |
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Journal | FEMS Microbiology Ecology |
Volume | 85 |
Issue number | 1 |
Pages (from-to) | 14-26 |
ISSN | 0168-6496 |
DOIs | |
Publication status | Published - 11 Feb 2013 |