Evaluation of biodegradation of 2-chlorobenzoic acid by isolated bacteria from landfill soils in Shiraz, Iran

Abstract

Chlorobenzoic acids are one of the environmental pollutants which contaminate the soils and waters. Microorganisms have been used for removing pollution in the area of oil spill, nuclear waste, leakage from waste landfill, factory waste, and heavy metals. The aim of this study was to identify 2-chlorobenzoic acid degrading bacteria from the soils around the landfill centers (landfills) in Shiraz city (Iran) and to evaluate their degradation rate. In this study, the surface soils of landfill from various stations were collected in the winter and spring and were inoculated to mineral base medium containing 0.1% of 2-chlorobenzoic acid and then incubated for one week at temperatures of 30°C. After three to four times sub culturing, bacteria were cultured on solid mineral medium, and then, they were incubated. Identification of bacteria using biochemical tests revealed 10 genus which comprised seven Gram-negative and three Gram-positive bacteria. These bacteria were considered as 2-chlorobenzoic acid resistant or degrading bacteria. Evaluation with high performance liquid chromatography (HPLC) confirmed that Pseudomonas species,Enterobacter species, Acinetobacter species, and Corynebacterium species were able to degrade 4.53, 4.48, 35, and 7.21% of 2-chlobenzoic acid in one week, respectively. Therefore, this study confirms the potential of these bacteria for use in biodegradation of 2-chlorobenzoic acid. Key words: 2-Chlorobenzoic acid, bioremediation, Pseudomonas, landfill, high performance liquid chromatography (HPLC).