Pentachlorophenol degradation by Pseudomonas fluorescens

Abstract

Fluorescent Pseudomonads strains were considered as plant growth promoting bacteria. They exhibited antagonistic activities against phytopathogens and showed bio-fertilizing properties. The strain Pseudomonas fluorescens PsWw128, isolated from wastewater, can use the pentachlorophenol (PCP) as the sole source of carbon and energy. High-performance liquid chromatography (HPLC) and spectrophotometric methods were used to follow the PCP degradation and biomass PsWw128 formation. However, the removal efficiency of PCP was highly significant. Thus, PsWw128 was able to degrade more than 99% of PCP when this isolate was grown under a high concentration of PCP (250 mg L–1) in a mineral salts medium (MSM). The simultaneous utilization of glucose and PCP indicates the diauxic growth pattern of PsWw128. PCP addition (100 mg L–1) in the growth medium can contribute to a decrease of the antibiotic susceptibility, and increase the biofilm development. In the presence of the toxic pollutant PCP (100, 200 and 250 mg L–1), the antibiotic sensitivity showed a decrease concerning the seven antibiotics tested. Furthermore, the biofilm formation appeared very low with OD600 = 0.075 in the Brain infusion broth supplemented with 25% of glucose, and developed a significant growth with an OD600 = 1.809 in the MSM supplemented with 250 mg L–1 of PCP.