Towards efficient crude oil degradation by Pseudomonas sp. strain-O2: Application of Plackett-Burman design for evaluation of cultivation conditions

Abstract

Towards an efficient crude oil bioremediation, optimization study of crude oil degradation by Pseudomonas sp. strain-O2 was done. Preliminary experiments of crude oil degradation revealed that peptone was the optimal nitrogen source recording 73.3% removal of crude oil, in the presence of 0.5 g/L of yeast extract. The increase of phosphate ratio to 2.5 led to 80.1% removal of crude oil.  To evaluate the significance of different culture conditions that affect crude oil biodegradation, Plackett-Burman factorial design was applied. Eleven variables were simultaneously examined. Among those variables, crude oil concentration was the highest positively significant variable that encourage crude oil degradation in Pseudomonas sp. strain-O2 affecting the degradation process, other factors namely, Na-succinate, (NH4)2SO4, KH2PO4 and MgSO4.7H2O showed moderate effect. While, yeast extract, inoculum concentration, agitation, K2HPO4and NaCl were the lowest significant variables. Fractional factorial design experiments indicated that the pre-optimized medium showed approximately 1.5-folds increase in crude oil degradation by Pseudomonas sp. strain-O2.   Key words: Biodegradation, crude oil, Pseudomonas sp., experimental design, optimization.