Plackett-Burman Design of Environmental and Nutritional Parameters for Petroleum Bioremediation by Penicillium chresogenum

Abstract

Bioremediation of diesel oil using microbial species is a promising method to remedy contaminated soil using Penicillium chresogenum. In this study, Plackett–Burman experiment is a new model for diesel oil degradation. It may save time and efforts relatively, simple in addition to making one experiment for many variables. In this study Plackett-Burman experimental design had been applied to estimate the significant of nutritional conditions affecting petroleum bioremediation by isolated Penicillium chresogenum. Eleven variables through 12 trials were studied in this experiment, namely ammonium sulphate, potassium carbonate, potassium dihydrogen phosphate, sodium dihydrogen phosphate, beef extract, spore suspension, sodium chloride, magnesium sulphate, calcium chloride, temperature and pH. It was found that four variables (spore suspension, (NH4)2SO4, Potassium Carbonate, and Magnesium sulphate) are affected the bioremediation process positively, while others (sodium dihydrogen phosphate, Beef extracts, Temperature, pH, Sodium chloride, NaCl and KH2PO4) have negative effects on oil bioremediation. Depending on petroleum weight loss calculations, and the above variables parameters the petroleum oil was removed by Penicillium chresogenum. Both, sodium chloride and temperature were found to inhibit its removal process. The experiment No (9) using Pencillium chresogenum was considered that the most suitable method for oil degradation with percentage removal of petroleum 97.9 %. On the hand, experiment No (10) the undesirable method for oil removal with percentage removal 4.09 %. Based on the experiment, a microbiological model is constructed to simulate microbial growth and oil decomposition. Biodegradation rate was influenced by oil concentration, temperature, water content and oxygen concentration.