摘要：Two yeast isolated from putrefied fruit pickles were studied for their acid and salt tolerance. The pickles were prepared by soaking salted Japanese apricots in Japanese apricot vinegar for over one year. The salt concentrations and pHs of the 12 homemade and one commercial variety of vinegar used were 22 to 25% and 2.3 to 2.6 respectively. Citric acid and malic acid were identified as the major organic acids in the vinegar. The two isolates had high acid tolerance and medium salt tolerance, growing well in an extremely acidic environment of pH 2.0 to 3.0. Their growth was completely inhibited at 1.5M NaCl below pH 3.0, and at 2.0M NaCl above pH 3.0. The addition of 50mM Mg2+ to the yeast extract-malt extract (YM) medium markedly facilitated their growth at 1.0 and 1.5M NaCl, but K+ and Ca2+ had no such stimulating effect under the same conditions.
