乳白耙齿菌F17好氧降解四溴双酚A的特性及机理研究

Characteristics and mechanism of aerobic biodegradation of tetrabromobisphenol A by Irpex lacteus F17

【目的】为了探究乳白耙齿菌F17(Irpex lacteus F17)降解溴代阻燃剂的可能性,研究了该菌好氧降解四溴双酚A(Tetrabromobisphenol A,TBBPA)的特性以及影响降解的因素,并结合降解产物的分析,推测其降解途径。【方法】采用高效液相色谱法测定TBBPA的浓度,并通过气相色谱-质谱联用仪分析降解过程的中间产物。【结果】I.lacteus F17可以通过共代谢的方式好氧降解TBBPA,最适共代谢基质是葡萄糖。在葡萄糖浓度为8 g/L、菌悬液接种量为5%、pH 5.0的优化条件下,当TBBPA初始浓度为20 mg/L时降解率可达85.5%,脱溴率为14.6%。对降解过程中锰过氧化物酶的研究发现TBBPA的降解率受到该酶活性的影响。通过气相色谱-质谱联用仪检测到7种中间产物。【结论】I.lacteus F17可以有效降解四溴双酚A,其降解机理主要包括脱溴、β-断裂、羟基化、去质子和氧化等过程。

[Objective]To research the possibilities of biodegradation of brominated flame retardants by Irpex lacteus F17,we studied the characteristics and influence factors of aerobic degradation of tetrabromobisphenol A(TBBPA),and the degradation pathway was speculated based on the analysis of intermediates.[Methods]We determined the concentration of TBBPA during biodegradation by high-performance liquid chromatography(HPLC),and detected the intermediate products by gas chromatography-mass spectrometry(GC-MS).[Results]TBBPA could be biodegraded by I.lacteus F17 via co-metabolism,and glucose was confirmed to be the most appropriate co-metabolic matrix.Under the optimal degradation conditions which were 8 g/L glucose,5%inoculum volume,pH 5.0,the degradation rate and the debromination rate were 85.5%and 14.6%,respectively,for 20 mg/L TBBPA.It was found that the degradation rate of TBBPA was related to the activity of manganese peroxidase(MnP).On the basis of GC-MS analysis,we detected seven intermediate products.[Conclusion]I.lacteus F17 could degrade TBBPA effectively,and debromination,β-scission,hydroxylation,deprotonation,and oxidation were involved in the degradation mechanism of TBBPA by Irpex lacteus F17.