Enzymatic bioreactors for the oxidation of estrogenic and anti-inflammatory compounds by laccases

Abstract

Over the past decade, public concern about the environmental impact of steroid estrogens present in municipal wastewaters has grown due to their potential for disturbing endocrine systems of animals and humans. Besides, the release of antiinflammatory drugs to the environment also implies a great concern because of their negative effects, e.g. potential cytotoxicity to liver and kidney of some species. The degradation of these types of compounds implies an important ecological challenge as they have complex structures and low bioavailability. In fact, they have been detected in wastewater treatment plant effluents at different concentrations ranging from nanograms to micrograms per liter, once conventional processes can only render partial transformation yields. Hence, alternative treatment methods have been investigate in order to overcome that environmental issue, such as physical methods (e.g. sorption and membrane separation), microbial removal by bacteria and algae and advanced oxidation processes (AOPs) (e.g. ozonation, UV/H2O2, Fenton, etc.). In general, AOPs provide high removal rates but low selectivity; however, these methods imply in some cases considerable high costs associated to reagents and/or investment, the formation of harmful byproducts and even the generation of compounds with estrogenicity higher than that of the parent substrate and/or non-biodegradable.