## 2 Materials and Methods
### Analytical Methods  
The whole content of the 250 mL flasks (_viz._ 50 \(\pm\) 1 mL) or 5-10 mL of the content of static Duran bottles was collected at predetermined intervals to correctly assess the kinetic studies. Yeast biomass (for the shake-flask trials) was harvested by centrifugation at 9055 \(g\), for 10 min at \(T\) = 21 \(\pm\) 1 \({}^{\circ}\)C (Suprafuge, Heraeus Sepatech), washed with distilled water and re-centrifuged again. Yeast cell concentration was determined gravimetrically by placement of wet biomass at \(T\) = 95 \(\pm\) 5 \({}^{\circ}\)C until constant weight (usually within 24 \(\pm\) 2 h) and was expressed as dry cell weight (DCW) (X, g/L). Intra-cellular polysaccharides (IPS, expressed as % _w/w_ in DCW) were measured by collecting 0.05 g of dry biomass weighted in a precision scale of four decimal digits (Ker new 420-3 NM) and placed in McCartney glass containers. The dried yeast cell mass was hydrolyzed using 10 mL of 2.5 M HCl at \(T\) = 80 \({}^{\circ}\)C for 30 min. The whole was neutralized to pH = 7.0 with 2.5 M NaOH and the volume was adjusted to 100 mL. Samples containing total sugars were then filtered (through No. 2 Whatman filters) and subjected to the DNS assay [28; 29]. Ethanol, glucose, fructose and glycerol were quantified through high performance liquid chromatography (HPLC) analysis carried out in a Waters Association 600E apparatus equipped with a RI detector (Waters 410). A Reexe ROA-Organic Acid H\({}^{+}\) column (300 mm \(\times\) 7.8 mm) (Phenomenex, Torrance, California, USA) was used for the separation of the compounds. The mobile phase was H\({}_{2}\)SO\({}_{4}\) at 0.005 M. The column temperature was set at \(T\) = 40 \({}^{\circ}\)C with a flow rate of 0.5 mL/min. The injection volume was 20 \(\mu\)L [26]. For quantitative analysis, standard solutions of the compounds were prepared in pure water (Milli-Q, Merk) at various concentrations. The range of concentration used to build the calibration curve for each compound analyzed (_viz._ glucose, fructose, glycerol, ethanol) was between 0.0 and 20.0 g/L. In the shake-flask experiments, dissolved oxygen concentration (DOC, in % _v/v_) was off-line determined using a selective electrode (OXI 96, B-SET, Germany) according to previously published procedure [29]. Before harvesting, the shaker was stopped and the probe was placed into the flask, after which the shaker was again switched on and the measurement was taken after DOC equilibration (within _ca_ 10 min). In all experiments, and irrespective of the initial concentration of glucose set in the medium or the used strain, DOC values were for all culture phases \(\geq\) 20% _v/v_, indicating that in the shake-flask experiments performed, full aerobic conditions were maintained [26; 29]. At the end of the microaerophilic/anaerobic trials, the volatiles of produced wines were determined using Gas Chromatography/Mass Spectrometry with Headspace Solid-Phase Micro-Extraction sampling (HS-SPME/GC-MS) [30]. Specifically, 2 mL of each wine sample was mixed with 7.5 mL of deionized water, 2 g of sodium chloride (dried at \(>\)100 \({}^{\circ}\)C prior to weighing), and 500 \(\mu\)L of 1,4-dioxane solution (1000 mg/L) as IS and placed in 20 mL glass vials. Each amber headspace vial was sealed with a cap (Teflon-lined septum) and placed in a water bath (40 \({}^{\circ}\)C) under constant stirring. Each vial was sealed with a silicone septum and placed in the water bath for 5 min reaching 40 \({}^{\circ}\)C under constant stirring (250 rpm). Subsequently, the SPME fibre (SPME; fibre DVB/CAR/PDMS, 2 cm; Sigma-Aldrich, Germany) was exposed to the headspace for 30 min at 40 \({}^{\circ}\)C under constant stirring. Then the fibre containing the absorbed volatiles was exposed in the injection port of the chromatograph (GC), in a split mode (split ratio 1/10), at 240 \({}^{\circ}\)C for 5 min.