Statistical evaluation and process optimization of biotreatment of polycyclic aromatic hydrocarbons in a bioreactor

Application of a biological treatment system using white rot fungi is an interesting alternative for treatment of water and wastewater
contaminated with persistent organic pollutants, such as polycyclic aromatic hydrocarbons (PAHs). A packed bed bioreactor using
the white rot fungi, Phanerochaete chrysosporium (P. chrysosporium) was evaluated for degradation of pyrene and phenanthrene
in polluted wastewater. White rot fungi have significant potential to metabolize organic pollutants such as PAHs by means of their
ligninolytic enzymes. This study examined the effect of feed flow rate (0.14 to 0.55 mL min-1) and initial PAHs concentrations in
feed (50 to 100 mg L-1). Response surface methodology (RSM) was applied to predict the degradation of PAHs available in influent
and enzyme activity. The RSM results showed that the best model for PAHs removal efficiency and enzyme activity is the reduced
quadratic model. The optimum region, identified based on four critical responses, was an influent flow of 0.35 mL min-1 and initial
pyrene and phenanthrene concentrations of 60 mg L-1. This resulted in 90% removal efficiency for pyrene and 87% for
phenenthrene and enzyme activity of 57 U L-1 for MnP and 426 U L-1 for LiP.