Molecular characterization of an n-alkane-degrading bacterial community and identification of a new species, Acinetobacter venetianus

Twenty-five bacterial strains isolated from the Venice lagoon and implicated in the degradation of n-alkanes, n-alkanots, n-alkanals and n-alkanoates were characterized in molecular and physiological terms. The isolates were grouped by amplified ribosomal DNA restriction analysis (ARDRA) into seven clusters, corresponding to seven species, six of which were identified on the basis of 16S rDNA sequencing. Genetic variability among strains was shown by random amplified polymorphic DNA (RAPD). Only strains of the new species Acinetobacter venetianus grew with n-alkanes (C₁₀, C₁₄ and C₂₀) their respective oxidation products as sole carbon sources. Strains of the other three species identified thrived on n-alkane oxidation products (n-alkanols, n-alkanals, n-alkanoates). The other three species were not able to grow on any of the substrates tested. Analysis of plasmid content showed that only A. venetianus strains harboured plasmids. These plasmids contained sequences homologous to the Pseudomonas oleovorans alkBFGH genes.