CHEMICAL ENGINEERING TRANSACTIONS VOL. 27, 2012 A publication of The Italian Association of Chemical Engineering Online at: www.aidic.it/cet Guest Editors: Enrico Bardone, Alberto Brucato, Tajalli Keshavarz Copyright © 2012, AIDIC Servizi S.r.l., ISBN 978-88-95608-18-1; ISSN 1974-9791 Biodegradation of Aromatic Compounds by a Halophilic Archaeon Isolated from the Dead Sea. Sara Cuadros-Orellana a , Metchild Pohlschröder b , Matthew J. Grossman c and Lucia R. Durrant c* a Centro de Pesquisas René Rachou (CPqRR/Fiocruz), Belo Horizonte-MG, Brazil b Department of Biology, School of Arts and Sciences, University of Pennsylvania, Philadelphia, PA, USA c Department of Food Science - FEA, University of Campinas (UNICAMP), Rua Monteiro Lobato, 80 CEP: 13083- 862 Campinas, São Paulo, Brazil durrant@fea.unicamp.br It is well established that aromatic compounds can be readily degraded in aerobic environments within soils, sediments and waters with salinities up to and including that of seawater. However, little is known about their metabolism in hypersaline environments. There is a growing interest in the development and optimization of bioremediation processes to deal with environments with high salinity that are contaminated with aromatic compounds. Among prokaryotes, haloarchaea are a group of microorganisms living in hypersaline environments that may have a greater potential in degrading pollutants than previously assumed and can be considered as a good environmental tool for bioremediation. We enriched and isolated 10 halophilic archaea from Dead Sea water samples on the basis of their ability to grow on p-hydroxybenzoic acid (pHBA) as the sole carbon and energy source. All isolates showed identical total lipid profiles, but are metabolically very diverse. Strain L1, which is also capable of growth on benzoic acid (BA), was chosen for biodegradation kinetics determination. When grown in BA, strain L1 produced small amounts of a compound that co-chromatographed with gentisic acid, which accumulated in the medium. The same did not occur when pHBA was the growth substrate. A discussion on the possible metabolic pathways involved is included, and a preliminary characterization of strain L1 is presented. 1. Introduction Thalassic (sea water-derived) hypersaline environments are usually characterized by low water activity and high temperatures. Biological activity dramatically decreases as sea water concentrates, as a consequence of a w reduction, and so does biological diversity. The Dead Sea contains 340 g/L total dissolved salts and is probably one of the most extreme examples of saline aquatic environments. Its waters are devoid of life except for local more diluted sections originated from rare abundant rainfall in the catchment area, mainly during winter, which may lead to discrete microbial blooms around the edges (Bodaker, et al, 2010). Since the pioneer studies by Benjamin Elazari Volcani on the microbiota of the Dead Sea in the early 1930s, a number of aerobic and anaerobic halophilic bacteria and archaea have been isolated from Dead Sea water and sediments, or detected through molecular or chemotaxonomic methods (Oren and Gurevich, 1995, Arahal et al. 1996, Rainey et al., 1995, Bodaker 13