Biological filter to remove estrogens from waste water and drinking water

 Published on June 26, 2012 Bielefeld University students participating in MIT competition A biological filter to remove estrogens from waste water and drinking water. The 15 Bielefeld students submitting this project to the 'international Genetically Engineered Machine competition' (iGEM) at the Massachusetts Institute of Technology (MIT) in Boston, USA are setting their sights high. They are persuading internationally active companies and associations in the biotechnology and chemistry sector to contribute several ten thousands of Euros to cover the costs of entering this rapidly expanding global competition in synthetic biology. Since May, they have been spending their free time in the laboratory making new DNA building blocks, reproducing them, and producing enzymes. First results give reason for optimism. The birth control pill is a widespread contraception method. However, large amounts of these modified estrogens leave the body again in urine. The conventional methods in sewage treatment plants are unable to treat this waste water sufficiently because the most frequently used estrogen ethinylestradiol is very difficult to break down. As a result, the hormone finds its way into rivers and lakes and also accumulates in drinking water with serious consequences for fish and other aquatic life. These range from reproductive and severe developmental disorders to the formation of female sexual characteristics in males. The long-term consequences of increasing estrogen pollution for human beings are still largely unknown. Nonetheless, declining sperm counts and thereby increasing infertility in men living in industrial nations may well relate to this hormonal pollution. In addition, testicular and prostate cancers as well as osteoporosis (a reduction in bone density) could be a consequence of overly high concentrations of estrogen in the human body.

Bio filters from tree fungi The goal of the Bielefeld iGEM team is to develop a biological filter in which certain enzymes (so-called laccases) break down the estrogen. Laccases are to be found in many organisms, and one of their properties is an ability to break down aromatic compounds - to which the estrogens belong. One source of particularly efficient laccases for this process is the turkey tail, a type of fungus that likes to grow on trees. The Bielefeld students are aiming to manufacture this enzyme economically and safely with the help of methods from synthetic biology. It should also be possible to extend the concept to other, in part poisonous and carcinogenic pollutants in drinking and waste water. The students already have one first success to announce: they have managed to isolate the genes of several laccases from various bacteria and have placed them in a standard, allowing further development. By the time of the European Jamboree in October, they want to have confirmed how the enzymes break down various substrates such as estrogens, pesticides, and pharmaceuticals and to be starting to immobilize them to filter materials.