Removal of 17a-ethinylestradiol from a sterile WC medium by the cyanobacteria Microcystis novacekii Isabela Araujo Fioravante, * a Bruna Albergaria, a Taciane Silveira Teodoro, b S ergia Maria Starling Magalh~ aes, c Francisco Barbosa b and Rodinei Augusti c Received 13th January 2012, Accepted 19th June 2012 DOI: 10.1039/c2em30320e An unprecedented investigation dealing with the removal of 17a-ethinylestradiol (EE2, a contraceptive hormone) by the cyanobacteria Microcystis novacekii (a species that is abundant and easily accessible in Brazilian lakes) from a sterile WC medium is described herein. The results indicated that whereas EE2 experienced insignificant spontaneous degradation, Microcystis novacekii was capable of removing ca. 65% of the hormone from the culture medium. Furthermore, no metabolites were detected at the concentration levels evaluated (0.10 to 0.17 mg L 1 ) as verified by the use of GC-MS, a quite sensitive analytical technique, and adequate pre-concentration procedures (SPME and liquid extraction). Elucidative experiments, including an appropriate cell lyses procedure, indicated that EE2 was likely accumulated within the cells (bioaccumulation) rather than adsorbed on the cellular membrane (biosorption). Moreover, the intra- and extracellular contents of EE2 were shown to be roughly complementary. Finally, the species was found to be highly tolerant to the hormone as its growth rates were higher in the test than in the control experiments. All these findings, therefore, point to the use of Microcystis novacekii as a potential agent to treat effluents contaminated with EE2. 1. Introduction EE2 (17a-ethinylestradiol) is a contraceptive hormone of worldwide consumption. Its non-metabolized fraction is usually excreted into wastewater and is not completely eliminated by the conventional sewage treatment. This has been a subject of growing concern mainly for the government departments dealing with water quality management and human health care. The occurrence of EE2, even at low concentrations (ppt), in water bodies can promote an enhancement in the estrogenic activity with pronounced negative effects on the local biota. 1,2 For instance, the incidence of EE2 at trace levels in a number of aquatic environments has caused a disturbing imbalance in the female population of several species. 3,4 The removal of organic pollutants from water bodies requires the development of novel approaches, especially biological treatments. The usual elevated stability of these substances, however, demands the employment of resilient microorganisms able to quickly and efficiently promote their removal via biotransformation/bioaccumulation. 1 Whereas heterotrophic microorganisms have been exhaustively tested for these purposes, recent studies have shown the remarkable benefits of using cyanobacteria as bioremediation agents as well as indica- tors of environmental pollution. 5 Cyanobacteria possess a notable capability to adapt to quite distinct environments which cause them to usually be the predominant microbiota in contaminated water bodies. 6 These microorganisms exhibit predominantly an autotrophic metabo- lism although mixotrophy can emerge under certain circum- stances. Additionally, some species are capable of nitrogen fixation. Besides these attractive features, the culture medium required for biodegradation tests demands exclusively the use of inorganic substances. This makes cyanobacteria potential agents of bioremediation, with likely superior performance in compar- ison with other heterotrophic microorganisms. 7 Whereas cyanobacteria can collect and metabolize xenobiotics, thus reducing the exposure of other species to deleterious chemical agents, they are at the base of the food chain and may accumulate toxic substances, thus increasing the contamination risks for higher organisms. For instance, recent studies have described the use of cyanobacteria to deal with different types of pollutants, such as pesticides, 8 dyes 9 and petroleum derivatives. 10 Hence, studies regarding the physiological and biochemical changes promoted by xenobiotics on such primary producers comprise another important role for evaluating environmental risks. 7 Previous studies have described the employment of fungi and bacteria to uptake EE2 from aqueous media. 11,12 The primary aim of the present study is therefore to evaluate the potential of a Laboratory of Mass Spectrometry, Department of Chemistry, Federal University of Minas Gerais, Belo Horizonte, Minas Gerais, 31270-901, Brazil. E-mail: isabelafioravante@yahoo.com.br; Fax: +55-31-3409 5734; Tel: +55-31-3409 5734 b Laboratory of Limnology, Department of General Biology, Federal University of Minas Gerais, Belo Horizonte, Minas Gerais, Brazil c Laboratory of Water, Department of Social Pharmacy, Federal University of Minas Gerais, Belo Horizonte, Minas Gerais, Brazil 2362 | J. Environ. Monit., 2012, 14, 2362–2366 This journal is ª The Royal Society of Chemistry 2012 Dynamic Article Links C < Journal of Environmental Monitoring Cite this: J. Environ. Monit., 2012, 14, 2362 www.rsc.org/jem PAPER Published on 13 July 2012. Downloaded by Federal University of Minas Gerais on 24/03/2015 12:12:27. View Article Online / Journal Homepage / Table of Contents for this issue