Anaerobic oxidation of o-xylene, m-xylene, and homologous alkylbenzenes by new types of sulfate-reducing bacteria.
Various alkylbenzenes were depleted during growth of an anaerobic, sulfate-reducing enrichment culture with crude oil as the only source of organic substrates. From this culture, two new types of mesophilic, rod-shaped sulfate-reducing bacteria, strains oXyS1 and mXyS1, were isolated with o-xylene and m-xylene, respectively, as organic substrates. Sequence analyses of 16S rRNA genes revealed that the isolates affiliated with known completely oxidizing sulfate-reducing bacteria of the delta subclass of the class Proteobacteria. Strain oXyS1 showed the highest similarities to Desulfobacterium cetonicum and Desulfosarcina variabilis (similarity values, 98.4 and 98.7%, respectively). Strain mXyS1 was less closely related to known species, the closest relative being Desulfococcus multivorans (similarity value, 86.9%). Complete mineralization of o-xylene and m-xylene was demonstrated in quantitative growth experiments. Strain oXyS1 was able to utilize toluene, o-ethyltoluene, benzoate, and o-methylbenzoate in addition to o-xylene. Strain mXyS1 oxidized toluene, m-ethyltoluene, m-isoproyltoluene, benzoate, and m-methylbenzoate in addition to m-xylene. Strain oXyS1 did not utilize m-alkyltoluenes, whereas strain mXyS1 did not utilize o-alkyltoluenes. Like the enrichment culture, both isolates grew anaerobically on crude oil with concomitant reduction of sulfate to sulfide.
Max-Planck-Institut für Marine Mikrobiologie, D-28359 Bremen, Germany.
G
G
Harms
K
K
Zengler
R
R
Rabus
F
F
Aeckersberg
D
D
Minz
R
R
Rosselló-Mora
F
F
Widdel
D000478:Alkylation; D000693:Anaerobiosis; D001482:Base Composition; D001555:Benzene Derivatives / Q000378:metabolism*; D001673:Biodegradation, Environmental; D003470:Culture Media; D004269:DNA, Bacterial / Q000737:chemistry / Q000235:genetics; D020459:Genes, rRNA; D008969:Molecular Sequence Data; D010084:Oxidation-Reduction; D010578:Petroleum; D010802:Phylogeny; D012336:RNA, Ribosomal, 16S / Q000235:genetics; D017422:Sequence Analysis, DNA; D013431:Sulfates / Q000378:metabolism*; D016999:Sulfur-Reducing Bacteria / Q000235:genetics / Q000254:growth & development / Q000302:isolation & purification* / Q000378:metabolism; D014871:Water Microbiology; D014992:Xylenes / Q000378:metabolism*
D001555:Benzene Derivatives; D003470:Culture Media; D004269:DNA, Bacterial; D010578:Petroleum; D012336:RNA, Ribosomal, 16S; D013431:Sulfates; D014992:Xylenes