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In order to establish the mechanism of occurrence of sunlight flavour of beer in continuation of the preceding paper, humulone, lupulone, and their analogues and degradation compounds, i.e., cohumulone, adhumulone, 5-acetyl-3-methylfilicinic acid including analogues, tetrahydrohumulone, hexahydrolupulone, humulinic acid and lupuloxinic acid, were tested for the occurrence of sunlight flavour of beer.As a result, among the above-mentioned compounds, humulone, lupulone, cohumulone, adhumulone, tetrahydrohumulone and hexahydrolupulone were found to cause the sunlight flavour, but the other compounds did not cause typical sunlight flavour. This fact shows that some specific structural components seem requisite for the occurrence of sunlight flavour of beer.It was also revealed that isomerization caused by boiling accelerates the occurrence of the sunlight flavour of beer. Finally, the result of the experiment conducted by the gas chromatographic procedure showed that any new component is not detected by the e...

l-Arabinose ketol isomerase (EC 5.3.1.4) was extracted from cells of Candida utilis which were grown in sulfite pulp mill waste.The enzyme was partially purified 135-fold by means of fractionation with ammonium sulfate, on DEAE-cellulose and DEAE-Sephadex A-50 column chromatographies and gel filtration on Sephadex G-200.Optimal pH and temperature for the activity of the enzyme were 7.0 and 60°C, respectively. The enzyme reaction was activated by Co2+ and Mn2+, and was inhibited by Na-pyrophosphate.The Michaelis-Menten’s constant for l-arabinose was 1.07×10−1m, and the thermodynamic quantities, ΔH, ΔG (35°C), ΔS (35°C) and E were 8914 cal/mole, −1397 cal/mole, 33.5 cal/deg mole and 9588 cal/mole, respectively.

微生物による水銀化合物の回収を目的とし,まず無機水銀化合物である昇汞について,その耐性菌をスクリーニングした結果,活性汚泥中にその耐性菌をみとめ,ついでこの菌を純粋分離し同定した結果, Aeromonasに属する細菌であることがみとめられた.ついで,本菌をもちいて昇汞を添加した培地で培養し,昇汞の菌体への取込みを調べた結果,菌体内分布については,破壊菌体を7500×g, 15分間で沈殿する区分に,その大部分が存在することをみとめた.

L-Arabinose ketol-isomerase (EC 5. 3. 1. 4) was extracted from the L-arabinose-grown cells of Clostridium acetobutylicum and partially purified by ammonium sulfate fractionation, DEAE-cellulose column chromatography and the gel filtration on Sephadex G-200. Optimum pH and temperature for the activity of the enzyme were 7.5 and 37°C, respectively. The enzyme was inhibited by EDTA, Na-pyrophosphate and KCN, and its activity was restored by the addition of divalent metal ions such as Mn2+ and Co2+. The Michaelis-Menten's constants for L-arabinose, Mn2+ and Co2+ were 1.08×10-2M, 0.83×10-4M and 0.38×10-4M, respectively. The equilibrium constant (K=ribulose/arabinose) was 3.14 (37◊C, pH 7.5). The thermodynamic quantities, ΔH, ΔG (37°C), ΔS (37°C) and E were +7354cal/mole, -710.7cal/mole, +26.0cal/(deg•mole) and +7471cal/mole, respectively.

Three synthetic lupulone analogues, i.e., 1-acetyl-3,3,5-tri-allyl-, 1-acetyl-3,3,5-tri-n-propyl-and 1-acetyl-3,3,5-tri-n-butyl-hexadiene- (1,5) -diol- (2,6) -on- (4) did not cause sunlight flavor of beer when they were added to a fermented solution of sucrose and exposed to sunlight.When methanol solutions of humulone and acetolupuphenonen were exposed to sunlight, changes in the UV-absorption spectra were observed. This fact indicates that humulone and acetolupuphenone underwent some photochemical reaction upon exposure to sunlight.Prenyl (γ,γ-dimethylallyl) mercaptan was synthesized, which gave a typical sunlight flavor when it was added, in a trace amount, to a fermented solution of sucrose.

自然界よりPMAおよびMA耐性菌をスクリーニングしたところ,活性汚泥中より耐性の強い菌を分離した.ついで本菌を同定したところ, Pseudomonas ovalisと確認された.また本菌の培養中におけるpH,菌体量, PMAおよびMAの取込み量などの経時的変化,ならびに菌体への取込まれ方について検討した結果, PMAおよびMAは破壊菌体を26,000×g, 15分間で沈降する区分に,大部分取込まれていることがみとめられた.

Xylose isomerase, an enzyme isomerizing xylose to xylulose, was produced adaptively when Candida utilis, a fodder yeast, was grown in a medium containing xylose. This experiment was carried out in order to isolate and purify the enzyme, and to clarify properties of the enzyme. As a result, it was revealed that the enzyme could be solubilized by plasmolysis, and was purified by dialysis, salting out with ammonium sulfate, precipitating with acetone, and adsorbing to calcium phosphate gel. The enzyme requires some divalent metal ions for its action and among them manganese ion is the most effective. The enzyme is inhibited particularly by ethylenediamine-tetraacetic acid and has somewhat thermotolerant character.

In a previous paper, the synthesis of β,-γ-hexenol from the Grignard reagent of pentenylbromide and formaldehyde has been reported.However, it was not established with certainty that the synthetic compound thus obtained was truly β,-γ-hexenol itself. Recently, Harper and Smith traced the procedure outlined in that paper and concluded that the synthetic products were not β,-γ-hexenol and as they mainly contained 2-ethylbut-3-en-l-ol and in addition unsaturated hydrocarbons.Here again, the earlier procedure was repeated on a larger scale.From this, it was recognized that β,-γ-hexenol is not to be gained, but 2-ethylbut-3-en-l-ol and unsaturated hydrocarbons are obtained in accordance with the experiment of Harper and Smith.

l-Arabinose ketol isomerase (EC 5.3.1.4) was extracted from cells of Candida utilis which were grown in sulfite pulp mill waste.The enzyme was partially purified 135-fold by means of fractionation with ammonium sulfate, on DEAE-cellulose and DEAE-Sephadex A-50 column chromatographies and gel filtration on Sephadex G-200.Optimal pH and temperature for the activity of the enzyme were 7.0 and 60°C, respectively. The enzyme reaction was activated by Co2+ and Mn2+, and was inhibited by Na-pyrophosphate.The Michaelis-Menten’s constant for l-arabinose was 1.07×10−1m, and the thermodynamic quantities, ΔH, ΔG (35°C), ΔS (35°C) and E were 8914 cal/mole, −1397 cal/mole, 33.5 cal/deg mole and 9588 cal/mole, respectively.

イチジク緑葉成分の中プソラレン,精油及び精油のフェノール部分の微生物に対する抗菌抗黴性を検討した.プソラレンは72時間後に於て細菌類には5千倍以下, Asp. oryzae 1万倍, Hans. anomala 10万倍でその発育を阻止した.精油及び精油のフェノール部分はプソラレンよりも抗菌性が劣っており,精油は72時間後に於て各微生物に対し5千倍以下の抗菌性を示す程度であり,精油のフェノール部分はB. subtilis, Staph. aureus及びPseud. fluorescensに対し2千倍, Asp. oryzae及びHans. anomalaに対し1千倍の稀釈濃度でその発育を阻止した.