Studies on NaCl-tolerance yeasts (2) : Salt-tolerance and the cellular characteristics in torulopsis yeasts

[Author abstract]Most of the strains of high NaCl-tolerant yeast belonged to genera Torulopsis. The stability of NaCl-tolerance, which had been considered to be gained by growing yeast in a medium containing sodium chloride (0-22%), was examined. We classified these yeast strains into four types by their NaCl-tolerance. They were halotolerant type, halophilic type, low-halophilic type and halophobic type. Two strains of wild yeasts, viz. T. glabrata and T. etchellsii were found very highly NaCl-tolerant (up to 22% NaCl) and both of them were very small in cell size. These yeasts were isolated from soya mash. Cell size of the halotolerant and halophilic type strains of Torulopsis yeasts isolated from sake cake pickle and soya mash were much smaller than these of low-halophilic or halophobic ones. Almost strains of halophilic, low-halophilic, halophobic and some of halotolerant strains showed smaller cell size if they were grown in the medium supplemented with high concentration of sodium chloride (15-20%). Some of halotolerant strains, however, did not show any significant difference in cell size by the addition of sodium chloride to the growth medium.[要約]1. 耐塩性により分離株を4型式に分類した。耐塩性: T. glabrata, T. etchellsii, S. rouxii 好塩性: T. pinus, T. famata, T. molischiana 弱塩性: T. globosa, T. inconspicua, T. aeria, T. candida, T. magnoliae 嫌塩性: Sacch. cerevisiae 2. 耐塩性株は弱塩性株に比し栄養細胞は一般に小さい｡3. 高濃度食塩添加培地では耐塩性株には細胞の変化するものと変化しないものとに分れた｡好塩性、弱塩性株は全て変化し細胞が小さくなった。4. 死滅細胞の出現は先ずdaughter cellが死滅し続いてその両側にBudding celllが形成しただちに死滅して終にはMother cellも同様活性を失い染色されclusterを形成する