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In order to remove the high content of malic acid (0.48%) in freshly fermented apple wine by applying malo-alcoholic fermentation(MAF) using malate-decomposing yeasts, Schizosaccharomyces japonicus var. japonicus or Schizosaccharomyces pombe, some factors which influenced malic acid decomposition in apple wine by malate-decomposing yeasts were investigated. By incubating the apple wine with these yeasts, 80% of initial malic acid was decomposed in 13 days at 20℃, whereas only 32% reduction in malic acid was observed in 40 days when MAF was not induced. For malic acid decomposition, Schizosaccharomyces pombe was superior to Schizosaccharomyces japonicus var. japonicus in natural medium such as apple wine, whereas Schizosaccharomyces japonicus var. japonicus was superior to Scloizosaceharomyces pombe in synthetic medium. The optimum temperature for the MAF using these yeasts was between 20 to 30℃ and no adverse effect was detected by the addition of SO₂ up to 200 ppm. Additions of Mg^(2+) or certain amino acids such as alanine, aspartic acid to the wine could enhance the composition of malic acid.
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