The pollution of waterbody and wastewater by endocrine disruptors is steadily increasing and is filtered by sewage treatment plants inadequately. Municipal and industrial wastewaters contain a variety of pollutants, such as estrogens and xeno-estrogens, which can cause severe disorders in humans and animals. By using synthetic estrogens in the place of natural estrogen in hormonal contraceptives, the natural hormone degradation is slowed down and the substances remain longer in water. The effect of hormonally active substances on the environment and humans is very complex. They can cause reduced fertility in both humans and animals and result in feminization of males and hermaphroditism, especially in aquatic animals. Besides the synthetic estrogen other chemical substances can also have the same effects on the nature, e.g. Bisphenol-A. These so-called endrocrine substances can also be detected in the body of water. These substances belongs to the chemical class of poly aromatic hydrocarbons. Polycyclic aromatic hydrocarbons (PAHs) emerge from burning fossil fuels. They are bioaccumulating, toxic and have a low biodegradability. Furthermore, numerous polycyclic aromatic hydrocarbons are cancerogen, which illustrates the danger they pose to the environment.

Synthetic estrogens and polycyclic aromatic hydrocarbons are among the substances, which can not be removed by conventional wastewater purification sufficiently. These micro contaminants effect associated aquatic or dependent terrestrial ecosystems and interfere with the existing or future uses of groundwater. Caused by the significant and sustained upward trends of concentrations of any pollutants in the waterbody the European Parlament is about to define limit values for the most problematical substances. To reduce the concentration of the micro contaminants in the waterbody it is nessasary to find new methods and systems. Synthetic biology and the use of laccases may offer solutions especially for such substances.

The Potential Solution

The goal of Bielefeld's iGEM team is to develop a concept based on immobilized laccases for municipal and industrial wastewater purification. Besides toxic aromatic compounds, synthetic estrogens, which are persistent in nature, should particularly be depleted from wastewater. Moreover, laccases are also able to dehalogenate chlorophenols and are therefore suitable for the bioremediation and restoration of lindane and PCBs (biochlorinated biphenyls) contaminated soil.

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