Citation:
Sandrine Paisse, Marisol Goni-Urriza, Frédéric Coulon and Robert Duran. Are alkane hydroxylase genes (alkB) relevant to assess petroleum bioremediation
processes in chronically polluted coastal sediments? Applied Microbiology and Biotechnology (2011) volume 92, Issue 4, pp835-844
Abstract:
The diversity of alkB-related alkane hydroxylase sequences and the relationship
between alkB gene expres- sion and the hydrocarbon contamination level have been
investigated in the chronically polluted Etang-de-Berre sediments. For this
purpose, these sediments were main- tained in microcosms and submitted to a
controlled oil input miming an oil spill. New degenerated PCR primers targeting
alkB-related alkane hydroxylase sequences were designed to explore the diversity
and the expression of these genes using terminal restriction fragment length
polymorphism fingerprinting and gene library analyses. Induction of alkB genes
was detected immediately after oil addition and their expression detected only
during 2 days, although the n-alkane degradation was observed throughout the 14
days of incubation. The alkB gene expression within triplicate microcosms was
heterogeneous probably due to the low level of alkB transcripts. Moreover, the
alkB gene expression of dominant OTUs has been observed in unoiled microcosms
indicating that the expression of this gene cannot be directly related to the
oil contamination. Although the dominant alkB genes and transcripts detected
were closely related to the alkB of Marinobacter aquaeolei isolated from an oil-
producing well, and to alkB genes related to the obligate alkanotroph
Alcanivorax borkumen- sis, no clear relationship between the oil contamination
and the expression of the alkB genes could be established. This finding suggests
that in such coastal environments, alkB gene expression is not a function
relevant enough to monitor bacterial response to oil contamination.