abstract
The potential of estuarine microniches as reservoirs of biosurfactant-producing bacteria was evaluated by testing different combinations of inocula and hydrophobic carbon sources. Selective cultures using diesel, petroleum, or paraffin as hydrophobic carbon sources were prepared and inoculated with water from the surface microlayer, bulk sediments, and sediment of the rhizosphere of Halimione portulacoides. These inocula were compared regarding the frequency of biosurfactant-producing strains among selected isolates. The community structure of the selective cultures was profiled using denaturing gradient gel electrophoresis (DGGE) of the 16S rRNA gene fragments at the end of the incubation. The DGGE profiles corresponding to the communities established in selective cultures at the end of the incubation revealed that communities were different in terms of structural diversity. The highest diversity was observed in the selective cultures containing paraffin (H-'=2.5). Isolates were obtained from the selective cultures (66) and tested for biosurfactant production by the atomized oil assay. Biosurfactant production was detected in 17 isolates identified as Microbacterium, Pseudomonas, Rhodococcus, and Serratia. The combination of estuarine surface microlayer (SML) water as inoculum and diesel as carbon source seems promising for the isolation of surfactant-producing bacteria. Supplemental materials are available for this article. Go to the publisher's online edition of Preparative Biochemistry and Biotechnology to view the supplemental file.
keywords
SEA-SURFACE MICROLAYER; POLYCYCLIC AROMATIC-HYDROCARBONS; PSEUDOMONAS-AERUGINOSA; BIOFILM FORMATION; OIL-SPILL; DEGRADING BACTERIUM; BACILLUS-SUBTILIS; CO-METABOLISM; DIESEL OIL; DEGRADATION
subject category
Biochemistry & Molecular Biology; Biotechnology & Applied Microbiology
authors
Domingues, PM; Louvado, A; Oliveira, V; Coelho, FJCR; Almeida, A; Gomes, NCM; Cunha, A
our authors
Patrícia Maia Domingues
PhD StudentGroups
acknowledgements
The authors are grateful to Fernando Fernandes for the airbrush used in the atomized oil assays and to Joao Coutinho for providing the light Arabian crude oil. This work was partially funded by the Centre for Marine and Environmental Studies (CESAM).