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- Title
Degradation of organic pollutants by methane grown microbial consortia.
- Authors
Hesselsoe, Martin; Boysen, Susanne; Iversen, Niels; Jørgensen, Lars; Murrell, J. Colin; McDonald, Ian; Radajewski, Stefan; Thestrup, Helle; Roslev, Peter
- Abstract
Microbial consortia were enriched from various environmental samples with methane as the sole carbon and energy source. Selected consortia that showed a capacity for co-oxidation of naphthalene were screened for their ability to degrade methyl-tert-butyl-ether (MTBE), phthalic acid esters (PAE), benzene, xylene and toluene (BTX). MTBE was not removed within 24 h by any of the consortia examined. One consortium enriched from activated sludge ("AAE-A2"), degraded PAE, including (butyl-benzyl)phthalate (BBP), and di-(butyl)phthalate (DBP). PAE have not previously been described as substrates for methanotrophic consortia. The apparent Km and Vmax for DBP degradation by AAE-A2 at 20 °C was 3.1 ± 1.2 mg l-1 and 8.7 ± 1.1 mg DBP (g protein × h)-1, respectively. AAE-A2 also showed fast degradation of BTX (230 ± 30 nmol benzene (mg protein × h)-1 at 20 °C). Additionally, AAE-A2 degraded benzene continuously for 2 weeks. In contrast, a pure culture of the methanotroph Methylosinus trichosporium OB3b ceased benzene degradation after only 2 days. Experiments with methane mono-oxygenase inhibitors or competitive substrates suggested that BTX degradation was carried out by methane-oxidizing bacteria in the consortium, whereas the degradation of PAE was carried out by non-methanotrophic bacteria co-existing with methanotrophs. The composition of the consortium (AAE-A2) based on polar lipid fatty acid (PLFA) profiles showed dominance of type II methanotrophs (83-92% of biomass). Phylogeny based on a 16S-rRNA gene clone library revealed that the dominating methanotrophs belonged to Methylosinus/Methylocystis spp. and that members of at least 4 different non-methanotrophic genera were present (Pseudomonas, Flavobacterium, Janthinobacterium and Rubivivax).
- Subjects
POLLUTANTS; BIODEGRADATION; MICROBIAL development; METHANE; PHTHALATE esters; BENZENE; FATTY acids; NAPHTHALENE; XYLENE; TOLUENE
- Publication
Biodegradation, 2005, Vol 16, Issue 5, p435
- ISSN
0923-9820
- Publication type
Article
- DOI
10.1007/s10532-004-4721-2