ENVIRONMENTAL MICROBIOLOGY Bacterial Community Composition of Biological Degreasing Systems and Health Risk Assessment for Workers Delphine Boucher & Jean Baptiste Laffaire & Faouzi Jaziri & Christine David & Corinne Biderre-Petit & Philippe Duquenne & Eric Peyretaillade & Pierre Peyret Received: 17 December 2010 /Accepted: 31 May 2011 # Springer Science+Business Media, LLC 2011 Abstract Biological degreasing system is a new technolo- gy based on the degradation capabilities of microorganisms to remove oil, grease, or lubricants from metal parts. No data is available about the potential biological health hazards in such system. Thus, a health risk assessment linked to the bacterial populations present in this new degreasing technology is, therefore, necessary for workers. We performed both cultural and molecular approaches in several biological degreasing systems for various industrial contexts to investigate the composition and dynamics of bacterial populations. These biological degreasing systems did not work with the original bacterial populations. Indeed, they were colonized by a defined and restricted group of bacteria. This group replaced the indigenous bacterial populations known for degrading complex substrates. Klebsiella pneumoniae, Klebsiella oxytoca, Pseudomonas aeruginosa, and Pantoea agglomerans were important members of the microflora found in most of the biological degreasing systems. These bacteria might represent a potential health hazard for workers. Electronic supplementary material The online version of this article (doi:10.1007/s00248-011-9887-7) contains supplementary material, which is available to authorized users. D. Boucher : J. B. Laffaire : F. Jaziri : E. Peyretaillade : P. Peyret Clermont Université, Université d’Auvergne, Laboratoire: Microorganismes Génome et Environnement (LMGE), BP 10448, F-63000 Clermont-Ferrand, France D. Boucher : J. B. Laffaire : F. Jaziri : C. Biderre-Petit : E. Peyretaillade : P. Peyret CNRS, UMR 6023, LMGE, F-63177 Aubière, France F. Jaziri Clermont Université, Université Blaise Pascal, Laboratoire d’Informatique, de Modélisation et d’Optimisation des Systèmes (LIMOS), BP 10448, F-63000 Clermont-Ferrand, France F. Jaziri CNRS, UMR 6158, LIMOS, F-63177 Aubière, France C. David Département Expertise et Conseil Technique, Institut National de Recherche et de Sécurité (INRS), 30 rue Olivier Noyer, F-75680 Paris Cedex 14, France C. Biderre-Petit Clermont Université, Université Blaise Pascal, LMGE, BP 10448, F-63000 Clermont-Ferrand, France P. Duquenne INRS, Laboratoire de Métrologie des Aérosols, rue du Morvan, CS60027, F-54519 Vandoeuvre-les-Nancy cedex, France P. Peyret(*) Laboratoire : Microorganismes Génome et Environnement, Campus des Cézeaux, 24 avenue des Landais, 63177 Aubière, France e-mail: pierre.peyret@iut.u-clermont1.fr Microb Ecol DOI 10.1007/s00248-011-9887-7