【摘要】 研究了金属离子(Fe2+、Mn2+、Cu2+、Zn2+)对黄孢原毛平革菌(Phanerochaete chrysosporium)降解十溴联苯醚(BDE209)的影响。通过4因素(Fe2+、Mn2+、Cu2+、Zn2+)、5水平(0、0.01 mmol/L、0.05 mmol/L、0.1 mmol/L、0.2mmol/L)正交试验优化了4种金属离子的配比。结果表明,在含1 mg/L BDE209的降解体系中,当Cu2+、Fe2+、Zn2+、Mn2+浓度依次为0.05 mmol/L、0.2 mmol/L、0.01 mmol/L、0.1 mmol/L时,生物量为1.74 g,降解率达到最大(86.76%)。对比金属离子影响BDE209降解率和生物量的效应曲线,降解率和生物量相关,但不完全呈正比。金属离子改变了反应体系pH值,提高了胞外酶活力,并在细胞内富集,从而影响白腐菌的生理代谢活动和BDE209的降解。更多还原

【Abstract】 This study aims to find the influence approaches of metal ions on the degradation of organic pollutants by microorganisms.An aerobic strain,Phanerochaete chrysosporium which is capable of decomposing many kinds of aromatic compounds,was selected for the biodegradation of decabrominated diphenyl ether(BDE209).The effects of metal ions(Cu2+,Fe2+,Zn2+,Mn2+) on the biodegradation of BDE209 were investigated.An orthogonal experiment including four factors(Fe2+,Mn2+,Cu2+,Zn2+) and five levels(0,0.01 mmol/L,0.05 mmol/L,0.1 mmol/L,0.2 mmol/L) was designed to optimize the reaction system.The results showed that the optimum combination of the factors was Cu2+(0.05 mmol/L),Fe2+(0.2 mmol/L),Zn2+(0.01 mmol/L),Mn2+(0.1 mmol/L).For the treatment of 1 mg/L BDE209,86.76% degradation efficiency was obtained with 1.74 g biomass.The effect curves of metal ions on the fungus growth and BDE209 degradation were plotted and then compared with one another.Under the condition of low concentration metal ions,BDE209 degradation had a significantly positive correlation with the fungus growth,but at higher levels the relation was different.In other words,high concentration biomass could not produce maximum biodegradation efficiency.The effect of metal ions on degrading process was further explored in the terms of pH value,extracellular enzymes and metals concentration of the fungus.Metal ions altered the pH value of degrading system to which promoted the growth of fungus and accelerated the activity of extracellular enzymes,and thus improved the degradation efficiency of BDE209.Main extracellular enzymes from Phanerochaete chrysosporium including Lignin Peroxidase(LiP),Manganese Peroxidase(MnP) and Laccase(Lac) were analyzed in relation to BDE209 degrading efficiency.The results showed that the breakage of BDE209 had stronger dependence on Lac than the others and Cu had great influence on production and activity of Lac.A large portion of metals combined with the fungus also took great effect on the physiological metabolism,in turn on the biodegradation of BDE209.更多还原