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The formation of methanol, ethanol, ethyl acetate, propanol-1, isobutyl alcohol, and amyl alcohols (mixture of 2-methylbutanol-l and 3-methylbutanol-1) in continuous wine making by kissiris-supported biocatalyst, in comparison with free cells, was studied. The effect of temperature was also examined. Methanol content was not affected by the process and temperature, but the concentrations of ethyl acetate, propanol-1, isobutyl alcohol, amyl alcohols (total content of 2-methylbutanol-l and 3-methylbutanol-1), and total volatiles determined plus methanol were reduced by the reduction of the temperature. Although the concentration of the main aromatic compound, ethyl acetate, was slightly reduced in the wine, its percentage content in the total volatiles determined plus methanol was increased. Continuous wine making by the aforementioned biocatalyst gave higher ethyl acetate concentrations compared to that with free cells.

Kissiris, γ-alumina, and calcium alginate were the supports for immobilization of a cryotolerant and alcohol-resistant strain of Saccharomyces cerevisiae species. Continuous wine-making with immobilized cells on each above support was performed at ambient and low temperatures. To evaluate the results of continuous wine-making with immobilized cells, batch fermentations were performed using immobilized and free cells separately, in the same range of temperatures. Fourfold higher ethanol productivities at room temperature and 10-fold higher productivities at low temperatures were obtained by continuous wine-making, in comparison to batch fermentations performed with free cells. Specifically, at 7 °C, ethanol productivities achieved by continuous wine making were 16.7, 13.8, and 23.2 g L-1 day-1 and by batch wine-making were 4.5, 5.1, and 5.6 g L-1 day-1, respectively, for kissiris, γ-alumina, and calcium alginate. For free cells ethanol productivity was 1.5 g L-1 day-1 at 7 °C. The three continuous systems were operated continuously for 80 days without any infection and diminution of the ethanol productivity. Also, the wines were produced with low total and volatile acidities. Keywords: Alcoholic fermentation; wine; continuous; batch; immobilized cells; Saccharomyces cerevisiae; psychrotolerant strain

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