Caractérisation préliminaire a partir de la lagune de Bizerte (Tunisie) des bactéries tolérantes aux hydrocarbures aromatiques polycycliques (haps)

Abstract

In order to isolate bacteria showing ability to degrade polycyclic aromatic hydrocarbons and to resist to heavy metals and antibiotics, water and sediment samples were taken in may 2004 at 16 stations distributed all over the Lagoon of Bizerte. To isolate bacterial strains from sediment samples, enrichment cultures on basal mineral salt medium supplemented with fluoranthene as unique carbon and energy source were performed. Morphological and biochemical tests were used to select and identify 130 isolates. The preliminary results showed that the polycyclic aromatic hydrocarbon degrading bacteria belong to various Gram-and Gram+ groups (70% and 30 % respectively). Gram- bacilli were prevalent (74 %). According to antibiotic and metal resistances (i.e Chromium, Cobalt, Iron, Nickel, Cadmium, Zinc, Copper and Lead), 90 % of the isolated strains were able to resist at least for two antibiotics and two different metals. In the majority of the cases, their capacity to degrade polycyclic aromatic hydrocarbons was associated with a multiple resistance (metals and/or antibiotics).