Phenanthrene removal in a selected Mexican soil by the fungus Penicillium frequentans:: Role of C:N ratio and water content

The purpose of this study was to determine the ability of the nonbasidiomycete, filamentous fungi Penicillium frequentans, isolated and grown on sugar cane bagasse pith, to remove phenanthrene in a solid-state culture. Additionally, the study investigated whether phenanthrene removal could be enhanced by manipulating the carbon-to-nitrogen ratio (C:N) and moisture content over a relatively short-term period (29 days). To evaluate the combined effect of moisture content and the C:N ratio, a combined experimental design, composed with a 22 factorial and both central and axial points, was used, It was shown that the moisture content (p < 0.0003) and the combined effect of moisture content and C:N ratio have a significant (p < 0.002) positive effect on the phenanthrene removal. It was also found that heterotrophic activity was not correlated to phenanthrene removal. An optimum phenanthrene removal efficiency of 74% was realized at a moisture content of 40% and a C:N ratio of 60. This suggests that Penicillium frequentans was able to effectively remove phenanthrene in a solid-state culture and that the combination of nutrient addition and moisture adjustment could enhance the phenanthrene removal activity.