Abstract

The role of exopolysaccharide (EPS), lipopolysaccharide (LPS) and outer membrane proteins (OMPs) in the tolerance of Pseudomonas fluorescens to pentachlorophenol (PCP) was investigated. Two strains of P. fluorescens were cultivated in R2A broth supplemented with 5.0 mmol l -1 sodium salicylate or 2.75 mmol l -1 EDTA, and the tolerance to PCP in the presence of these compounds was determined. In addition, the expression of OMPs was also studied by using electrophoresis in polyacrylamide-SDS-urea gels. Sodium salicylate inhibited the biofilm formation of both strains. Neither sodium salicylate nor EDTA modified the levels of tolerance to PCP, indicating that such tolerance was not related to structures such as EPS or LPS. Three OMPs (46.9 to 88.1 kD) modified their expression levels in the presence of PCP. The results suggest that the observed tolerance to PCP in the strains might be associated with OMP expression.