Degradation of polynuclear aromatic hydrocarbons by two strains of Pseudomonas

Abstract

The goal of this investigation was to isolate competent polynuclear aromatic hydrocarbonsdegraders that can utilize polynuclear aromatic hydrocarbons of former industrial sitesat McDoel Switchyard in Bloomington, Indiana. Using conventional enrichment methodbased on soil slurry, we isolated, screened and purified two bacterial species strains PB1 andPB2. Applying the ribotyping technique using the 16S rRNA gene analysis, the strains wereassigned to the genus Pseudomonas (Pseudomonas plecoglossicida strain PB1 and Pseudomonassp. PB2). Both isolates showed promising metabolic capacity on pyrene sprayed MS agarplates during the preliminary investigations. Using time course studies in the liquid culturesat calculated concentrations 123, 64, 97 and 94 ppm for naphthalene, chrysene, fluroantheneand pyrene, P. plecoglossicida strain PB1 and Pseudomonas sp. PB2 showed partial utilizationof the polynuclear aromatic hydrocarbons. Naphthalene was degraded between 26% and40%, chrysene 14% and 16%, fluroanthene 5% and 7%; pyrene 8% and 13% by P. plecoglossicidastrain PB1 and Pseudomonas sp. PB2 respectively. Based on their growth profile, we developeda model R2= 1 to predict the degradation rate of slow polynuclear aromatic hydrocarbon-degraders where all the necessary parameters are constant. From this investigation, weconfirm that the former industrial site soil microbial communities may be explored for thebiorestoration of the industrial site.