A Microcosm Study on P-Nitrophenol Biodegradation in Soil Slurry By Alcaligenes Faecalis: Plackett-Burman Design

Contamination of soils with nitroaromatic hydrocarbons, due to their toxic effects, is one of the environmental issues. therefore, the purpose of this study is to examine para-nitrophenol (pnp) biodegradation in a microcosm consisting of kaolan clayey soil by a. faecalis, the superior bacterium among the four examined bacterial species. preliminary experiments were performed in slurry phase to investigate biodegradation of pnp by a. faecalis in shaking flasks at initial concentrations of 25 and 50mgkg-1 which resulted in 72 and 57% pnp removals after 20 days, respectively. to identify the effective factors on pnp biodegradation, experiments were carried out in shake flasks at various levels of eight factors, i.e. pnp, glucose and yeast concentrations, temperature, soil-water ratio, initial ph, inoculum size as well as pnp concentration in pre-exposure based on plackett-burman design method. results showed 20.9 up to 75.5% pnp removal in soil slurry after 12 days within the design space. analysis of variance revealed that temperature, inoculum size, yeast extract concentration, ph and soil-water ratio are the most effective factors on pnp biodegradation, respectively.