APPLIED MICROBIAL AND CELL PHYSIOLOGY Very early acetaldehyde production by industrial Saccharomyces cerevisiae strains: a new intrinsic character Naoufel Cheraiti & Stéphane Guezenec & Jean-Michel Salmon Received: 2 October 2009 / Revised: 20 October 2009 / Accepted: 25 October 2009 / Published online: 18 November 2009 # Springer-Verlag 2009 Abstract During a general survey of the acetaldehyde- producing properties of commercially available wine yeast strains, we discovered that, although final acetaldehyde production cannot be used as a discriminating factor between yeast strains, initial specific acetaldehyde produc- tion rates were of highly interest for classifying yeast strains. This parameter is very closely related to the growth- and fermentation-lag phase durations. We also found that this acetaldehyde early production occurs with very different extent between commercial active dry yeast strains during the rehydration phase and could partially explain the known variable resistance of yeast strains to sulfites. Acetaldehyde production appeared, therefore, as very precocious, strain-dependent, and biomass-independent character. These various findings suggest that this new intrinsic characteristic of industrial fermenting yeast may be likely considered as an early marker of the general fermenting activity of industrial fermenting yeasts. This phenomenon could be particularly important for under- standing the ecology of colonization of complex fermenta- tion media by Saccharomyces cerevisiae. Keywords Yeast . Acetaldehyde . Anaerobiosis . Alcoholic fermentation Introduction Acetaldehyde is considered to be a leakage product of alcoholic fermentation by yeasts; it has the unusual properties of being highly reactive and biologically toxic. There are differences in acetaldehyde production between different yeast species and strains: from 0.5 to 700 mg L −1 (Liu and Pilone 2000). Exogenously added acetaldehyde at ≥400 mg L −1 lengthened the lag phase and decreased the exponential specific growth rate of Saccharomyces cerevi- siae in a medium lacking ethanol (Stanley et al. 1997). In contrast, low levels of acetaldehyde may stimulate yeast growth (Barber et al. 2002b). For example, ≤580 mg L −1 acetaldehyde shortens the lag phase and increases the specific growth rate of S. cerevisiae in the presence of 3–6% (v/v) ethanol but not in the absence of ethanol (Stanley et al. 1993; Walker-Caprioglio and Parks 1987). In addition, very low levels of acetaldehyde (<100 mg L −1 ) were found to greatly reduce the lag phase of ethanol- or temperature-stressed S. cerevisiae (Stanley et al. 1997). It was recently demonstrated by a transcriptomic approach that the stimulatory effect of a small quantity of added acetaldehyde to yeast cultures is only observed in cells subject to ethanol-stress, alleviating ethanol-induced growth inhibition (Mohammed 2007). Dur- ing experiments to assess the effects of exogenously added acetaldehyde during the growth phase on subsequent yeast fermentation kinetics, we previously reported that acetalde- hyde perfusion could alleviate the phenotypic effect of zinc deficiency during alcoholic fermentation, by restoring the capacity of the yeast cells to regenerate nicotinamide adenine dinucleotide (NAD; Cheraiti et al. 2007). Collectively, these observations suggest that acetalde- hyde exchange between strains could inhibit the growth of some yeast strains while encouraging the growth of others (Cheraiti et al. 2005). This phenomenon could be particu- larly important for understanding the ecology of the colonization of complex fermentation media by S. cerevi- siae after elimination of non-Saccharomyces yeasts. During spontaneous fermentations, a succession of different indig- N. Cheraiti : S. Guezenec : J.-M. Salmon (*) UMR 1083 “Sciences pour l’œnologie”, INRA, 2 place Viala, 34060 Montpellier Cedex 1, France e-mail: jmsalmon@supagro.inra.fr Appl Microbiol Biotechnol (2010) 86:693–700 DOI 10.1007/s00253-009-2337-5