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Anaerobic utilization of alkylbenzenes and n ‐alkanes from crude oil in an enrichment culture of denitrifying bacteria affiliating with the β‐subclass of Proteobacteria
Author(s) -
Ralf Rabus,
Heinz Wilkes,
Andreas Schramm,
Gerda Harms,
Astrid Behrends,
Rudolf Amann,
Friedrich Widdel
Publication year - 1999
Publication title -
environmental microbiology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.954
H-Index - 188
eISSN - 1462-2920
pISSN - 1462-2912
DOI - 10.1046/j.1462-2920.1999.00014.x
Subject(s) - denitrifying bacteria , alkylbenzenes , biology , bacteria , enrichment culture , proteobacteria , microbiology and biotechnology , food science , 16s ribosomal rna , denitrification , biochemistry , nitrogen , chemistry , organic chemistry , genetics , catalysis
Denitrifying bacteria were enriched from freshwater sediment with added nitrate as electron acceptor and crude oil as the only source of organic substrates. The enrichment cultures were used as laboratory model systems for studying the degradative potential of denitrifying bacteria with respect to crude oil constituents, and the phylogenetic affiliation of denitrifiers that are selectively enriched with crude oil. The enrichment culture exhibited two distinct growth phases. During the first phase, bacteria grew homogeneously in the aqueous phase, while various C 1 –C 3 alkylbenzenes, but no alkanes, were utilized from the crude oil. During the second phase, bacteria also grew that formed aggregates, adhered to the crude oil layer and emulsified the oil, while utilization of n ‐alkanes (C 5 to C 12 ) from the crude oil was observed. During growth, several alkylbenzoates accumulated in the aqueous phase, which were presumably formed from alkylbenzenes. Application of a newly designed, fluorescently labelled 16S rRNA‐targeted oligonucleotide probe specific for the Azoarcus / Thauera group within the β‐subclass of Proteobacteria revealed that the majority of the enriched denitrifiers affiliated with this phylogenetic group.