Long-Term Voyages and Bone Mass Among Seamen

東京水産大学海洋生産学専攻東京水産大学練習船海鷹丸東京水産大学練習船神鷹丸東京水産大学練習船海鷹丸東京水産大学練習船海鷹丸東京水産大学練習船神鷹丸東京水産大学練習船神鷹丸東京水産大学練習船海鷹丸東京水産大学練習船神鷹丸東京水産大学海洋生産学科東京水産大学海洋生産学

炭化水素資化性酵母Candida sp. Y-191の培養条件(炭化水素資化性酵母に関する研究(第2報),自然科学)

前報で,同定株,未同定株合せて309株を供試菌として炭化水素資化性酵母の検索を行い,26株の酵母を選択した。その中でも赤木が四日市市の油浸土壌から分離したCandida sp. Y-191号菌は増殖速度,菌体収量などの点ですぐれていることを認めたので,本報ではCandida sp. Y-191についてその生育におよぼすn-Hexadecane濃度の影響,種種の天然、栄養源添加の効果および本菌の各種n-Alkaneの資化性について検討した。n-Hexadecane濃度は低い程菌体収率が高く0.5%濃度では90.5%に達した。また,最高生育量を得たのは2.0%であった。本菌は天然栄養源の添加なしでもよく生育したが,Yeast extract, Corn steep liquor, Meat extract, Peptone等の添加によって生育速度が増大した。Yeast extractは0.01%で効果的であった。11種類のn-Alkane(C_8～C_)の資化性は,炭素数の増大とともに酵母量が増大する傾向がみられた。特にC_～C_のn-Alkaneを基質とした場合酵母収量が多かった。In the previous paper, screening of yeast that assimilate hydrocarbons and the effects of various nitrogen sources and surfactants on the growth of hydrocarbon assimilating yeast, Candida sp. Y-191, which had been isolated from oily soil by M. Akaki, one of the authors, were investigated. The basal medium containing 1% n-Hexadecane as carbon source was used. In this report, the effects of concentration of n-Hexadecane in the medium and the addition of natural nutrients to the basal medium such as yeast extract, meat extract, koji extract, corn . steep liquor and peptone, on the growth of Candida sp. Y-191, were investigated in shaking culture, using the basal medium (n-Alkane, (NH_2)_2CO 1.4g, KH_2PO_4 2.5g, MgSO_4・7H_2O 0.1g, FeSO_4・7H_2O 0.01g, Yeast extract 0.2g, Span 85 0.005g, Distilled water 1000ml, pH5.5～6.0). Also the ability of assimilation of individual pure n-Alkanes (n-C_8～n-C_) by the yeast were investigated. Following results were obtained. As shown in Table 2, the yield of the yeast cell on the basis of added n-Hexadecane increased, together with the decrease of n-Hexadecane concentration in the medium. The yield reached 90.5% with the medium containing 0.5% n-Hexadecane. The yield of the yeast cell on the basis of a definite amount of the medium was maximum, with the medium containing 2% n-Hexadecane. This yeast strain was able to grow comparatively well in the n-Hexadecane containing synthetic medium without addition of natural nutrients. However, by the addition of natural nutrients such as yeast extrct, meat extract and corn steep liquor, the yeast grew abundantly. The addition of 0.01% yeast extract to the medium was effective for the yeast growth. As shown in Table 3, the yeast assimilated hydrocarbons of n-Alkanes, n-C_9 to n-C_ and especially n-C_, n-C_ and n-C_ with good cell production. The yield of yeast cell generally tended to increase with increment of carbon number of n-Alkanes tested