Constructing a synthetic oestrogen degradation pathway

View all posters

Tamar Schwarz

University of Glasgow and Cefas, United Kingdom

The presence of endocrine disrupting chemicals (EDCs) in surface waters has been linked to a number of adverse effects in aquatic organisms; an increasing body of literature attempts to link EDCs with human endocrine and developmental disorders too. Ethinyl-oestradiol (EE2) is by far the most potent and recalcitrant EDC to date; as the active ingredient of the contraceptive pill it is also highly ubiquitous. The need to improve the removal of EE2 from wastewater in a cost-effective manner has become increasingly important and we believe the solution lies in the construction of a synthetic biodegradation pathway. Hence the focus of this project is to investigate bacterial and fungal enzymatic degradation of EE2 so that these can then be used as parts in a steroid breakdown pathway. Laccases are multi-copper oxidases well known for degrading phenolic and aromatic compounds; however, there are still gaps in the knowledge in terms of the EE2 degradation process. In order to assess the bioremediation potential of laccases our main aim is to elucidate the oestrogenicity and structure of the metabolites produced. Since the nature of the metabolites is unknown, we are employing two bioassays that measure oestrogenic activity. The more relevant of the two, is a new biosensor we developed in collaboration with the Institute of Natural Sciences (Japan) – a mammalian cell host with a fish oestrogen receptor coupled to a luciferase reporter. This biosensor is highly important because the detrimental effect of EE2 exposure to fish populations is very well documented. Here we present our preliminary results on laccases ability to degrade EE2, along with the oestrogenic profile of the metabolites produced. Where possible the chemical structures of major metabolites will be also included.