乳白耙齿菌F17对共存菲、蒽的降解差异性

Selective degradation of coexisting phenanthrene and anthracene by Irpex lacteus F17

【目的】通过对影响乳白耙齿菌F17 (Irpex lacteus)降解共存菲、蒽因素的研究,比较共存的菲和蒽降解性能的不同,并结合降解中间产物的分析,初步探讨其降解途径。【方法】采用GC-MS测定菲和蒽的浓度,并通过质谱图分析降解产物。【结果】共存的菲和蒽在初始浓度均为5 mg/L时生物降解率较高,分别为93%和85%以上。乳白耙齿菌F17在pH 3.0–8.0能较好地降解共存的菲,在pH 4.0–8.0范围内可较好地降解共存的蒽。菲的生物降解过程对低温的适应性比共存的蒽要好,共存体系的最适降解温度是30°C。在酶的作用下,蒽转化成邻苯二甲酸,菲转化为邻苯二甲酸或邻苯二酚。【结论】实验结果表明,当菲和蒽共存时,不同条件下乳白耙齿菌F17对菲的降解效果均比蒽要好,而且菲的总降解速率比蒽要快,作为同分异构体的菲和蒽,由于3个苯环位置的不同而表现出降解性能和降解途径上的差异性。

[Objective] To compare the differences of degradation properties of coexisting phenanthrene and anthracene, we studied factors affecting the degradation by Irpex lacteus F17. We also discussed the degradation pathway preliminarily combining with the analysis of intermediate products.[Methods] We determined the concentration of phenanthrene and anthracene by GC-MS, and analyzed the intermediate products of biodegradation with mass spectrogram.[Results] When the initial concentration of phenanthrene and anthracene was 5 mg/L, 93% of the former and 85% of the latter was degraded. Phenanthrene could be degraded preferably between pH 3.0 and 8.0, and coexisting anthracene could be degraded well between p H 4.0 and 8.0 by Irpex lacteus F17. Phenanthrene was degraded better than anthracene at low temperature, and the optimal temperature for coexisting system was 30 °C. Anthracene was transformed into phthalic acid, whereas phenanthrene was converted into phthalic acid or catechol by enzymes.[Conclusion] The results indicated that phenanthrene was degraded better and faster than coexisting anthracene by Irpex lacteus F17 under different conditions. There were some differences between coexisting phenanthrene and anthracene on degradation properties and degradation pathways due to the different positions of the three benzene rings.