Isolation and characterization of Alicycliphilus denitrificans strain BC, which grows on benzene with chlorate as the electron acceptor
article
A bacterium, strain BC, was isolated from a benzene-degrading chlorate-reducing enrichment culture. Strain BC degrades benzene in conjunction with chlorate reduction. Cells of strain BC are short rods that are 0.6 μm wide and 1 to 2 μm long, are motile, and stain gram negative. Strain BC grows on benzene and some other aromatic compounds with oxygen or in the absence of oxygen with chlorate as the electron acceptor. Strain BC is a denitrifying bacterium, but it is not able to grow on benzene with nitrate. The closest cultured relative is Alicycliphilus denitrificans type strain K601, a cyclohexanol-degrading nitrate-reducing betaproteobacterium. Chlorate reductase (0.4 U/mg protein) and chlorite dismutase (5.7 U/mg protein) activities in cell extracts of strain BC were determined. Gene sequences encoding a known chlorite dismutase (cld) were not detected in strain BC by using the PCR primers described in previous studies. As physiological and biochemical data indicated that there was oxygenation of benzene during growth with chlorate, a strategy was developed to detect genes encoding monooxygenase and dioxygenase enzymes potentially involved in benzene degradation in strain BC. Using primer sets designed to amplify members of distinct evolutionary branches in the catabolic families involved in benzene biodegradation, two oxygenase genes putatively encoding the enzymes performing the initial successive monooxygenations (BC-BMOa) and the cleavage of catechol (BC-C23O) were detected. Our findings suggest that oxygen formed by dismutation of chlorite can be used to attack organic molecules by means of oxygenases, as exemplified with benzene. Thus, aerobic pathways can be employed under conditions in which no external oxygen is supplied. Copyright © 2008, American Society for Microbiology. All Rights Reserved.
Topics
BiochemistryBiodegradationCatalystsCell cultureDegradationEncoding (symbols)EnzymesGene encodingGenesNitratesOxygenOxygenationProteinsBenzene biodegradationsBenzene degradationsBiochemical datumCyclohexanolDioxygenase enzymesDismutaseDismutationElectron acceptorsEncodingEnrichment culturesExternal-Gene sequencesGenes encodingIn cellsIsolation and characterizationsMonooxygenaseMonooxygenationsOrganic moleculesOxygenaseOxygenasesPcr primersPrimer setsShort rodsBenzenebacterial enzymebenzenebenzene oxygenasecatecholcatechol 1,2 dioxygenasechloratechlorite dismutaseestradiol dioxygenasenitrateoxygenaseunclassified drugbacteriumbenzenebiochemistrybiodegradationcatabolismchloritedenitrificationdetection methodelectronenzyme activitygene expressionmutationnitrateoxic conditionsoxygenpolymerase chain reactionAlicycliphilus denitrificansarticlebacterial growthbacterial strainbacterium isolatebiodegradationelectron transportenergy yieldgene amplificationgene sequencegenetic codenonhumannucleotide sequenceoxygenationphylogenypolymerase chain reactionProteobacteriaunindexed sequenceBacterial ProteinsBenzeneChloratesComamonadaceaeDioxygenasesDNA, BacterialDNA, RibosomalGenes, rRNALocomotionMixed Function OxygenasesMolecular Sequence DataNitratesNitritesNitrogenOxidoreductasesOxygenPhylogenyPolymerase Chain ReactionRNA, BacterialRNA, Ribosomal, 16SSequence Analysis, DNASequence Homology, Nucleic AcidAlicycliphilus denitrificansBacteria (microorganisms)Negibacteria
TNO Identifier
241078
ISSN
00992240
Source
Applied and Environmental Microbiology, 74(21), pp. 6672-6681.
Pages
6672-6681
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