title: Ethyl tert-butyl ether (ETBE) biodegradation by a syntrophic association of Rhodococcus sp. IFP 2042 and Bradyrhizobium sp. IFP 2049 isolated from a polluted aquifer.
abstract: Ethyl tert-butyl ether (ETBE) enrichment was obtained by adding contaminated groundwater to a mineral medium containing ETBE as the sole carbon and energy source. ETBE was completely degraded to biomass and CO2 with a transient production of tert-butanol (TBA) and a final biomass yield of 0.37 ± 0.08 mg biomass (dry weight).mg(-1) ETBE. Two bacterial strains, IFP 2042 and IFP 2049, were isolated from the enrichment, and their 16S rRNA genes (rrs) were similar to Rhodococcus sp. (99 % similarity to Rhodococcus erythropolis) and Bradyrhizobium sp. (99 % similarity to Bradyrhizobium japonicum), respectively. Rhodococcus sp. IFP 2042 degraded ETBE to TBA, and Bradyrhizobium sp. IFP 2049 degraded TBA to biomass and CO2. A mixed culture of IFP 2042 and IFP 2049 degraded ETBE to CO2 with a biomass yield similar to the original ETBE enrichment (0.31 ± 0.02 mg biomass.mg(-1) ETBE). Among the genes previously described to be involved in ETBE, MTBE, and TBA degradation, only alkB was detected in Rhodococcus sp. IFP 2042 by PCR, and none were detected in Bradyrhizobium sp. IFP 2049.
authors.affiliation: Environmental Microbial Genomics, CNRS, École Centrale de Lyon, Université de Lyon, Ecully, France, yoann.le-digabel@ifpen.fr.
authors.forename: Yoann
authors.initials: Y
authors.lastname: Le Digabel
authors.forename: Sandrine
authors.initials: S
authors.lastname: Demanèche
authors.forename: Yves
authors.initials: Y
authors.lastname: Benoit
authors.forename: Timothy M
authors.initials: TM
authors.lastname: Vogel
authors.forename: Françoise
authors.initials: F
authors.lastname: Fayolle-Guichard
mesh_terms: D018533:Biomass; D001711:Biotransformation; D020369:Bradyrhizobium / Q000302:isolation & purification / Q000378:metabolism*; D002245:Carbon Dioxide / Q000378:metabolism; D004269:DNA, Bacterial / Q000737:chemistry / Q000235:genetics; D004275:DNA, Ribosomal / Q000737:chemistry / Q000235:genetics; D005019:Ethyl Ethers / Q000378:metabolism*; D060587:Groundwater / Q000382:microbiology*; D008969:Molecular Sequence Data; D012336:RNA, Ribosomal, 16S / Q000235:genetics; D012240:Rhodococcus / Q000302:isolation & purification / Q000378:metabolism*; D017422:Sequence Analysis, DNA; D014873:Water Pollutants / Q000378:metabolism*
chemical_list: D004269:DNA, Bacterial; D004275:DNA, Ribosomal; D005019:Ethyl Ethers; D012336:RNA, Ribosomal, 16S; D014873:Water Pollutants; D002245:Carbon Dioxide; C098546:ethyl tert-butyl ether