Degradation of single and mixed PAHs by Irpex lacteus F17

Abstract:

[Objective] Here we studied the biodegradation characteristics of single and mixed polycyclic aromatic hydrocarbons (PAHs) pollutants by Irpex lacteus F17 using phenanthrene, anthracene, and fluoranthene. [Methods] We determined the concentration of PAHs during biodegradation using gas chromatography-mass spectrometer (GC-MS). We used pseudo first order reaction kinetics model to fit the biodegradation results of PAHs. [Results] After 15 days of degradation, the biodegradation rate was phenanthrene (97.8%) > anthracene(89.3%) > fluoranthene (81.5%). The degradation process of phenanthrene, anthracene and fluoranthene had the characteristics of pseudo first order reaction kinetics. The biodegradation rate of phenanthrene was the fastest, followed by anthracene, and fluoranthene was the slowest. Compared with the degradation of single PAHs, mixed PAHs showed different characteristics on the growth and manganese peroxidase synthesis of Irpex lacteus F17. In addition, water solubility was likely to be an important control factor for the biodegradation of mixed pollutants. The water solubility was in the following order:phenanthrene > fluoranthene > anthracene. Therefore, when we added phenanthrene or fluoranthene into anthracene degradation system, microorganisms may preferentially degrade these pollutants and inhibit the degradation of anthracene. The addition of anthracene or phenanthrene could also inhibit the biodegradation of fluoranthene. However, the addition of anthracene or fluoranthene with poor water solubility had no significant effect on the biodegradation of phenanthrene. [Conclusion] The competition role was the main characteristic for the biodegradation of mixed PAHs.