Qualitative and quantitative study of interaction between <em>Saccharomyces cerevisiae</em> and <em>Leuconostoc oenos</em>

Abstract

&lt;p style="text-align: justify;"&gt;Weak malolactic fermentations in wine making are often attributed to the medium constituents such as ethanol and SO&lt;sub&gt;2&lt;/sub&gt;. However, some authors report that the interactions between &lt;em&gt;&lt;em&gt;Saccharomyces cerevisiae&lt;/em&gt;&lt;/em&gt; and &lt;em&gt;Leuconostoc oenos&lt;/em&gt; could be responsible too.&lt;/p&gt;&lt;p style="text-align: justify;"&gt;The aim of this work is to characterize the influence of &lt;em&gt;S. cerevisiae&lt;/em&gt; on the growth of &lt;em&gt;L. oenos&lt;/em&gt;. First, a qualitative study was performed on solid medium containing 8 g/l of L-malic acid. In this case, &lt;em&gt;L. oenas&lt;/em&gt; was mixed to M.R.S agar and poured into Petri plate, then &lt;em&gt;S. cerevisiae&lt;/em&gt; was seeded in rings on the agar surface. After incubation, the coculture result in an inhibition of &lt;em&gt;L. oenos&lt;/em&gt; growth by &lt;em&gt;S. cerevisiae&lt;/em&gt;.&lt;/p&gt;&lt;p style="text-align: justify;"&gt;In order to quantify this phenomenon, a culture of &lt;em&gt;L. oenas&lt;/em&gt; was carried out on liquid medium prefermented by &lt;em&gt;S. cerevisiae&lt;/em&gt; (supplied with M.R.S nutrients) and was compared with a control on M.R.S medium. Both contained 8 g/l of L-malic acid. This technique allows to separate the microorganisms in order to avoid competitions between the strains.&lt;/p&gt;&lt;p style="text-align: justify;"&gt;The prefermented medium affects &lt;em&gt;L. oenos&lt;/em&gt; growth and the malolactic fermentation, but the results depended on the pH and the temperature. Globally, low pH (3,4) and high temperature (30°C) conditions increased the inhibitory effect of the prefermented medium. This medium contains inhibitory molecules for &lt;em&gt;L. oenas&lt;/em&gt;. In agreement with some authors, those molecules could be the medium chain fatty acids (C&lt;sub&gt;8&lt;/sub&gt; to C&lt;sub&gt;12&lt;/sub&gt;) released in the medium by &lt;em&gt;S. cerevisiae&lt;/em&gt; because of their pH-dependent toxicity. However, those results may be different with other couples of strains of &lt;em&gt;S. cerevisiae&lt;/em&gt; and &lt;em&gt;L. oenos&lt;/em&gt;.&lt;/p&gt;

Antagonistic interaction between yeasts and lactic acid bacteria of oenological relevance

“…Our previous studies indicated that yeast strains used in this work are poor fatty acid producers. Another possible explanation for inhibition of LAB growth proposed by certain authors is the depletion of nutrients by wine yeasts during AF (Gilis, Dupuy, & Strehaiano, 1996;Nygaard & Prahl, 1997). However, in the present work, prior to sequential inoculation with LAB, the yeastfermented media were supplemented with MRS components to rule out the lack of nutrients (see Materials and methods).…”

The inhibitory activity of wine yeast starters on malolactic bacteria

“…Our knowledge of the interactions between yeast and bacteria in the wine environment remains incomplete, and further investigations are required to determine the specific role of yeast with respect to the MLB (Edwards and Beelman, 1987;Lemaresquier, 1987;Gilis et al, 1996;Addis et al, 2001;Arnink et al, 2002). Indeed, previous studies have indicated that many factors can negatively influence the regular development of MLF (Britzh and Tracey, 1990;Radler, 1990;Guerzoni et al, 1995;Reguant et al, 2000;Vidal et al, 2001).…”

“…Several studies have demonstrated that there are a large number of parameters that can affect correct bacterial growth, and consequently MLF (Capucho and San Romao, 1994;Wibowo et al, 1985;Gilis et al, 1996). In particular, after yeast fermentation, the MLB are in a very harsh environment that is mainly due to the ethanol that is produced, which is the first inhibitory factor of MLB growth (Capucho and San Romao, 1994).…”

Interactions betweenSaccharomyces cerevisiaeand malolactic bacteria: preliminary characterization of a yeast proteinaceous compound(s) active againstOenococcus oeni

“…Traditionally, the control of MLF in wine has been carried out by using the chemical antiseptic agent SO 2 . More recently, the use of lysozyme and nisine has been proposed to protect wine and other fermented beverages (Ogden 1986; Radler 1990a,b; Gilis et al. 1996) from the activity of spoilage lactic acid bacteria, and the effect of yeast–MLB interactions in wine has started to be explored.…”

“…Traditionally, the control of MLF in wine has been carried out by using the chemical antiseptic agent SO 2 . More recently, the use of lysozyme and nisine has been proposed to protect wine and other fermented beverages (Ogden 1986;Radler 1990a,b;Gilis et al 1996) from the activity of spoilage lactic acid bacteria, and the effect of yeast-MLB interactions in wine has started to be explored. Indeed, further knowledge of the interactions occurring between wine micro-organisms is required, either for the evaluation of the possibility of controlling undesired MLB activities by means of natural antibacterial agents produced by yeast, or for the avoidance of any negative interactions in all the cases in which MLF has to be promoted.…”