过氧化物酶对水中17β-雌二醇光降解的影响机制

The effect mechanism of peroxidase on the photodegradation of 17β-estradiol in water

过氧化物酶广泛存在于天然水体,在外加过氧化氢(H_(2)O_(2))的条件下可有效地降解水体中的有机污染物.17β-雌二醇(E2)是水体中常见的雌激素,低浓度下仍具有极强的内分泌干扰效应,过氧化物酶可通过利用腐殖质产生的H_(2)O_(2);从而影响腐殖质介导的E_(2)的光化学过程,但其是否可直接影响E2的光转化尚不清楚.本文系统地研究了辣根过氧化物酶(HRP)对E_(2)光降解过程的影响.研究发现有活性的HRP可显著促进E2的光化学转化,且促进作用随着活性的增大而增强.活性氧猝灭实验结果表明E_(2)自敏化产生的活性物种可激活HRP,从而促进了E_(2)在光照条件下的酶降解,且E_(2)在HRP溶液中的光解产物实验进一步证实了这一过程.HRP对E2酶降解的效率高于常见水质成分Suwannnee River Humic Acid(SRHA)和Fe^(3+)的促进效率,弱于NO_(3)^(-)引起的促进效率,表明HRP对污染物在天然水体中的环境归趋的影响是值得关注的.本文为深入认识雌激素的环境归趋提供科学数据,并为酶处理技术在水处理方面的应用带来巨大前景.

Peroxidase is widely widespread in aqueous environment,it can effectively degrade organic pollutants in the presence of hydrogen peroxide (H_(2)O_(2)).17β-estradiol (E_(2)),as a common estrogen,exhibits strong endocrine disrupting effect even at relatively low concentration.It is well known that peroxidase can affect humus induced photochemical process of E_(2) via the interaction with H_(2)O_(2),while whether peroxidase can directly interact with E_(2) still remains unclear.In this study,the impact of horseradish peroxidase (HRP) on photochemical transformation of E_(2) was systematically evaluated.Our results revealed that active HRP could significantly promote the photodegradation of E_(2),and the promotion effect increased with the augment of enzyme activity.Self-sensitization of E2 was proposed to activate HRP,leading to the formation of a series of reactive oxygen species (ROS),which in turn oxidized E_(2).Such mechanisms were further verified by ROS quenching experiments and photoproducts identification.In addition,the promotion effect of HRP was found to be more pronounced than water components Suwannnee River Humic Acid (SRHA)and Fe^(3+),while less effective than nitrate,indicating that the involvement of HRP in the environmental fate of pollutants in natural water is noteworthy.The present study would provide scientific data for better understanding of the environmental fate of estrogen and bring great prospects for the application of enzyme treatment technology in water treatment.