Pyrene is a tetracyclic aromatic hydrocarbon with a symmetrical structure which is one of the top 129 pollutants as ranked by the U.S Environmental Protection Agency (USEPA). The aim of this study was assaying of pyrene degradation by isolated bacteria from soil of the landfills in Shiraz and evaluation of their growth kinetic. In this study, sampling from three different stations was conducted in landfills areas in the city of Shiraz, Iran. The bacterial strains with better growth on the enriched mediums were isolated and then identified by standard bacteriological tests. The isolated bacteria including Mycobacterium sp., Corynebacterium sp., Nocardia sp., Pseudomonas sp., Rhodococcus sp. and Micrococcus sp. were potentially capable of degrading pyrene hydrocarbon. They showed high growth rate during screening by increasing the optical density (OD600). The pyrene biodegradation value evaluated by high performance liquid chromatography (HPLC) was 89.1%, 79.4%, 75.3%, 68.2%, 62.3% and 56.8% for each strain respectively 10 days after incubation. The highest pyrene degradation rate was found in Mycobacterium sp. and Corynebacterium sp. with 89.1% and 79.4% values; therefore these bacteria could be used to clean the soils which are polluted with pyrene.
