MUST DEACIDIFICATION WITH AN INDUCED FLOCCULANT YEAST-STRAIN OF SCHIZOSACCHAROMYCES-POMBE

The use of flocculant cells of the yeast strain Schizosaccharomyces po mbe for the deacidification of grape musts in continuous culture was d eveloped. An external loop reactor was used to induce flocculation. Th e flocs obtained were stable in the pH range 3.0-6.0 and in the presen ce of several sugars. Some inhibition was observed for high (above 6.0 ) and low (below 3.0) pH values. Once induced, flocculation could no l onger be completely inhibited. Vinho Verde, a typical Portuguese wine, has a relatively low ethanol content and a high acid concentration. T he external loop reactor loaded with the flocculant cells was used to deacidify a synthetic medium with sugar and malic acid concentrations similar to the ones found in Vinho Verde grape must. A desirable malic acid decrease with moderate glucose consumption was obtained at a dil ution rate of 0.7 h-1. Improved results were obtained when the synthet ic medium was replaced by Vinho Verde grape must.