Ciliate contributions to bioaggregation: laboratory assays with axenic cultures of Tetrahymena thermophila Authors Susana Serrano Department of Microbiology III, Faculty of Biology, Complutense University of Madrid, Spain María Linares Department of Microbiology III, Faculty of Biology, Complutense University of Madrid, Spain Blanca Pérez-Uz Department of Microbiology III, Faculty of Biology, Complutense University of Madrid, Spain Almudena Guinea Department of Microbiology III, Faculty of Biology, Complutense University of Madrid, Spain Keywords: Tetrahymena thermophila, waste water treatment, flocculation, extracellular polymeric substances (EPS) Abstract Protists, mainly ciliates, play several essential roles in biological wastewater treatment, such as the transfer of matter and energy, bacterial predation, and the removal of organic material. Moreover, during the treatment process, the formation of bioaggregates—flocs and biofilms—is essential to obtaining high-quality effluents. In the present study, Tetrahymena thermophila was used as a model organism to demonstrate the contribution of ciliates to bioflocculation. Axenic cultures of this species were exposed to chemical and mechanical stimuli that promote bioaggregation. In either case, the secretion of a capsulate mucous material by the ciliates or by particle aggregation was detected. Numerous, small, loosely compacted flocs were observed under shaking conditions and in the presence of latex beads. The composition of the exopolymeric material secreted by ciliates was analyzed by a series of fluorochromes and colorimetric methods, which showed that carbohydrates and nucleic acids were the main components involved in matrix formation and particle adhesion. [Int Microbiol 2007; 10(2):91-96] Author Biographies Susana Serrano, Department of Microbiology III, Faculty of Biology, Complutense University of Madrid, Spain Department of Microbiology III, Faculty of Biology, Complutense University of Madrid, Spain María Linares, Department of Microbiology III, Faculty of Biology, Complutense University of Madrid, Spain Department of Microbiology III, Faculty of Biology, Complutense University of Madrid, Spain Blanca Pérez-Uz, Department of Microbiology III, Faculty of Biology, Complutense University of Madrid, Spain Department of Microbiology III, Faculty of Biology, Complutense University of Madrid, Spain Almudena Guinea, Department of Microbiology III, Faculty of Biology, Complutense University of Madrid, Spain Department of Microbiology III, Faculty of Biology, Complutense University of Madrid, Spain Downloads PDF Published 2010-01-26 Issue Vol. 10 No. 2 (2007) Section Research Articles License Submission of a manuscript to International Microbiology implies: that the work described has not been published before, including publication in the World Wide Web (except in the form of an Abstract or as part of a published lecture, review, or thesis); that it is not under consideration for publication elsewhere; that all the coauthors have agreed to its publication. The corresponding author signs for and accepts responsability for releasing this material and will act on behalf of any and all coauthors regarding the editorial review and publication process.If an article is accepted for publication in International Microbiology, the authors (or other copyright holder) must transfer to the journal the right–not exclusive–to reproduce and distribute the article including reprints, translations, photographic reproductions, microform, electronic form (offline, online) or any other reproductions of similar nature. Nevertheless, all article in International Microbiology will be available on the Internet to any reader at no cost. The journal allows users to freely download, copy, print, distribute, search, and link to the full text of any article, provided the authorship and source of the published article is cited. The copyright owner's consent does not include copying for new works, or resale. In these cases, the specific written permission of International Microbiology must first be obtained.Authors are requested to create a link to the published article on the journal's website. The link must be accompanied by the following text: "The original publication is available on LINK at <http://www.im.microbios.org>. Please use the appropiate URL for the article in LINK. Articles disseminated via LINK are indexed, abstracted, and referenced by many abstracting and information services, bibliographic networks, subscription agencies, library networks, and consortia.