ORIGINAL ARTICLE Study of the coumarate decarboxylase and vinylphenol reductase activities of Dekkera bruxellensis (anamorph Brettanomyces bruxellensis) isolates L. Godoy 1 , D. Garrido 1 , C. Martı´nez 1 , J. Saavedra 2 , M. Combina 3 and M.A. Ganga 1 1 Departamento de Ciencia y Tecnologı´a de los Alimentos, Facultad Tecnolo ´ gica, Universidad de Santiago de Chile, Alameda, Santiago, Chile 2 Pontificia Universidad Cato ´lica de Valparaı´so, Escuela de Alimentos, Centro Regional de Estudios en Alimentos Saludables (CREAS), Valparaı´so, Chile 3 Estacio ´ n Experimental Agropecuaria, Mendoza, INTA, Luja ´ n de Cuyo, Argentina Introduction Dekkera bruxellensis has been described as the main spoilage micro-organism in red wines (Loureiro and Malfeito-Ferreira 2003; Sua ´rez et al. 2007). Its presence in wines is associated with the detection of phenolic fla- vours that have a negative impact on the organoleptic characteristics of the wine (Chatonnet et al. 1992). As a result, much of the research on D. bruxellensis has been focused on the development of detection methods (Rodrigues et al. 2001; Cocolin et al. 2004) and few works have been carried out on its physiological charac- terization (Dias et al. 2003; Silva et al. 2004; Romano et al. 2008). Only in recent years have genetic studies been published (Conterno et al. 2006; Martorell et al. 2006; Curtin et al. 2007; Woolfit et al. 2007). The pro- duction of these undesired phenolic compounds by D. bruxellensis may be through the metabolization of cinnamic acids found in plant cell walls (Barthelmebs et al. 2001). These acids are associated with an antimi- crobial function (Stead 1995), such that micro-organisms able to ferment plant products show enzymatic activities that allow metabolizing less toxic compounds. For this, the cinnamic acids are decarboxylated into vinylphenol derivatives by the action of a coumarate descarboxylase (CD) activity and then reduced to an ethyl derivative through a vinylphenol reductase (VR) activity (Chaton- net et al. 1992). Some studies have shown differences between D. bruxellensis isolates in the production of these phenolic aromas (Conterno et al. 2006). However, these differences remain unexplained making it necessary to perform studies to find a possible explanation. Keywords Dekkera, fermentation, phenolic, wine, yeast. Correspondence Marı ´a Ange ´ lica Ganga, Edificio de Alimentos, Universidad de Santiago, Obispo Manuel Uman ˜ a 050, Estacion Central, Santiago, Chile. E-mail: angelica.ganga@usach.cl 2008 ⁄ 0687: received 22 April 2008, revised 28 October 2008 and accepted 20 November 2008 doi:10.1111/j.1472-765X.2009.02556.x Abstract Aim: To evaluate the coumarate descarboxylase (CD) and vinylphenol reduc- tase (VR) activities in Dekkera bruxellensis isolates and study their relationship to the growth rate, protein profile and random amplified polymorphic DNA (RAPD) molecular pattern. Methods and Results: CD and VR activities were quantified, as well, the growth rate, intracellular protein profile and molecular analysis (RAPD) were determined in 12 isolates of D. bruxellensis. All the isolates studied showed CD activity, but only some showed VR activity. Those isolates with the greatest growth rate did not present a different protein profile from the others. The FASC showed a relationship between RAPD molecular patterns and VR activity. Conclusion: CD activity is common to all of the D. bruxellensis isolates. This was not the case with VR activity, which was detected at a low percentage in the analysed micro-organisms. A correlation was observed between VR activity and the RAPD patterns. Significance and Impact of the Study: This is the first study that quantifies the CD and VR enzyme activities in D. bruxellensis, demonstrating that these activ- ities are not present in all isolates of this yeast. Letters in Applied Microbiology ISSN 0266-8254 452 Journal compilation ª 2009 The Society for Applied Microbiology, Letters in Applied Microbiology 48 (2009) 452–457 ª 2009 The Authors