乳白耙齿菌F17对单一和复合多环芳烃的降解差异解析

Degradation of single and mixed PAHs by Irpex lacteus F17

摘要:

[目的] 针对菲、蒽、荧蒽多环芳烃（PAHs）污染物，利用乳白耙齿菌F17，研究单一和复合PAHs污染物的生物降解规律。[方法] 采用气相色谱-质谱法（GC-MS）分析降解过程中PAHs的浓度，并采用准一级反应动力学模型对降解结果进行拟合。[结果] 对于单一PAHs，第15天时菲、蒽、荧蒽的降解率由高到低依次为菲（97.8%） > 蒽（89.3%） > 荧蒽（81.5%）。菲、蒽和荧蒽的降解过程具有准一级反应动力学特征，菲的生物降解速率最快，其次是蒽，荧蒽的降解速率最慢。与单一PAHs的降解相比，在复合PAHs的降解过程中，乳白耙齿菌F17的生长和锰过氧化物酶的合成均表现出不同的特征。此外，水溶性极可能是复合污染物降解的重要控制因子，三者水溶性为：菲 > 荧蒽 > 蒽。因此，在菲或荧蒽加入条件下，微生物能优先降解这些污染物，抑制了污染物蒽的降解；同时，蒽或菲的存在对荧蒽的降解也有抑制作用；然而外源加入水溶性较差的蒽和荧蒽，则对菲的生物降解无显著影响。[结论] 复合PAHs的生物降解主要表现为相互竞争的特点，通过GC-MS分析了PAHs的生物降解途径。

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.