Ethanol physiology in the warehouse-staining fungus, Baudoinia compniacensis Juliet O. EWAZE a,b , Richard C. SUMMERBELL a,b , James A. SCOTT a,b, * a Dalla Lana School of Public Health, University of Toronto, Toronto, ON Canada M5T 1R4 b Sporometrics Inc., 219 Dufferin St, Suite 20C, Toronto ON Canada M6K 1Y9 article info Article history: Received 31 December 2007 Received in revised form 22 April 2008 Accepted 1 May 2008 Corresponding Editor: Nicholas P. Money Keywords: Alcohol dehydrogenase Biodeterioration Capnodiales Glyoxylate cycle Torula compniacensis abstract The fungus Baudoinia compniacensis colonizes the exterior surfaces of a range of materials, such as buildings, outdoor furnishings, fences, signs, and vegetation, in regions subject to periodic exposure to low levels of ethanol vapour, such as those in the vicinity of distillery aging warehouses and commercial bakeries. Here we investigated the basis of ethanol metabolism in Baudoinia and investigate the role of ethanol in cell germination and growth. Germination of mycelia of Baudoinia was enhanced by up to roughly 1 d exposure to low ethanol concentrations, optimally 10 ppm when delivered in vapour form and 5 mM in liquid form. However, growth was strongly inhibited following exposure to higher ethanol concentrations for shorter durations (e.g., 1.7 M for 6 h). We found that ethanol was catabolized into central metabolism via alcohol dehydrogenase (ADH) and acetaldehyde dehydrogenase (ACDH). Isocitrate dehydrogenases (IDHs) were active in cells grown on glucose, but these enzymes were not expressed when ethanol was provided as a sole or companion carbon source. The glyoxylate cycle enzymes isocitrate lyase (ICL) and malate synthase (MS) activities observed in cells grown on acetate were comparable to those reported for other microorganisms. By replenishing tricarboxylic acid (TCA) cycle intermediates, it is likely that the functionality of the glyoxylate cycle is important in the establishment of luxuriant growth of Baudoinia compniacensis on ethanol-exposed, nutri- ent-deprived, exposed surfaces. In other fungi, such as Saccharomyces cerevisiae, ADH II catalyses the conversion of ethanol to acetaldehyde, which then can be metabolized via the TCA cycle. ADH II is known to be strongly repressed in the presence of glucose. ª 2008 The British Mycological Society. Published by Elsevier Ltd. All rights reserved. Introduction Tourists visiting distillery facilities in France where cognac and armagnac are held for ageing are likely to be told about ‘‘la part des anges’’ (‘‘the angels’ share’’), the annual 2 % loss of ethanol by distilled spirits stored in traditional wooden casks. At the same time, they are shown a black fungus that forms a conspicuous, sooty covering wherever these escaping ethanol vapours contact nearby walls, fences, tree trunks, and other exterior surfaces. Despite the constant attention, the fungus involved in this growth has received almost no scien- tific study since it was described as Torula compniacensis (liter- ally, ‘‘the torula from Cognac’’) in 1881 (Richon & Petit 1881). A significant obstacle has been that the microscopically nonde- script and very slow growing fungus is difficult to obtain in pure culture, tending to be overgrown by competitors. Recently, the organism was isolated into pure culture from several locations around the world, and was investigated by nuclear ribosomal gene sequencing. It was revealed as belonging to an undescribed genus in the order Capnodiales * Corresponding author. E-mail address: james.scott@utoronto.ca journal homepage: www.elsevier.com/locate/mycres mycological research xxx (2008) 1–8 ARTICLE IN PRESS 0953-7562/$ – see front matter ª 2008 The British Mycological Society. Published by Elsevier Ltd. All rights reserved. doi:10.1016/j.mycres.2008.05.003 Please cite this article in press as: Juliet O Ewaze et al., Ethanol physiology in the warehouse-staining fungus, Baudoinia comp- niacensis, Mycological Research (2008), doi:10.1016/j.mycres.2008.05.003