Nobuzo Tsumura

Enzymatic Conversion of D-Glucose to D-Fructose

Enzymes which catalyze the interconversion of free aldopentose and ketopentose have been demonstrated in several bacterial strains. Concerning the conversion of free hexoses, however, the cases reported are few. Palleroni and Doudoroff1) described mannose isomerase in Pseudomonas saccharophila, which converted mannose to fructose. Marshall and Kooi2) then reported the ability of Pseudomonas hydrophila to isomerise D-glucose to D-fructose. Recently, Bartfay3) suggested the presence of glucose isomerase in barley malt. This report presents the results of investigation on a bacterial strain which also has glucose isomerization activity. METHODS Isolation of Strain. Humus collected from the outskirts of Tokyo and other places were dispersed in sterile water and one drop each of the supernatant was inoculated into 10ml portions of liquid medium in test tubes, which contained D-xylose as sole carbon source (Table I). These tubes were maintained at 30°C for 2~3 days

Enzymatic Conversion of d-Glucose to d-Fructose: Part VIII. Propagation of Streptomyces phaeochromogenus in the Presence of Cobaltous IonPart IX. Dehydration and Preservation of the Cell as Enzyme Sourse

Propagation of Streptomyces phaeochromo genus by both shaking and submerged cultivations is described. The addition of Co++ to medium remarkably improved the activity of the cell to convert glucose into fructose. The cell grown with Co++ isomerized glucose at pH 9.0 and 7.5 similarly, whereas the cells grown without Co++ reacted with glucose at pH 9.3 as the optimum. In submerged cultivation, the mode of pH change during cultivation period varied depending on the kind of strain, carbon source and the presence of Co++.In the propagation of the strain SK, carbon and nitrogen sources were rather rapidly consumed resulting in cell growth, when pH value of the medium was falling. On the other hand, however, growth hardly developed at the pH values lower than 6.0.Therefore, it was necessary to adjust pH with alkali in order to get active cell yield.Dehydration and preservation of the cell of Streptomyces phaeochromogenus were investigated. Cell activity was changed differently during dehydration and preservatio...

Radiation Sterilization of Fermentation Raw Materials

グルコースイソメラーゼ生産菌streptomyces PhaeochromgenusStrain SKを用いてβ線照射による培養基の殺菌を試みた。その結果培養液のpH条件をととのえれば, 通常のオートクレープ殺菌のように炭素源と窒素源を分離して処理する必要はなく, 両者を混合して照射殺菌出来る可能性がみられた。又, 放射線照射による微生物の発育阻害物質を抑制するためcysteinの添加を試みたが, 特に明確な効果はみられなかった。なお, 放射線殺菌によってみられる初期の増殖のおくれは, 酸性PHにおげる照射で, 培養基の破壊もしくは阻害物質の生成があるものと推定される。

Enzymatic Conversion of d-Glucose to d-Fructose: Part V Partial Purification and Properties of the Enzyme from Aerobacter cloacaePart VI, Properties of the Enzyme from Streptomyces phaeochromogenus

Glucose isomerizing enzyme was partially purified after investigation on the properties of crude enzyme extract. The crude extract was partly inactivated by the contact with air. The addition of manganese was effective to improve the stability. Magnesium was essential to the enzyme action and cobalt accelerated the reaction.The maximal activity was observed at pH about 7.6 and 50°C was optimal for the incubation time of 30 minutes. The enzyme solution reacted with d-xylose as well as d-glucose. The activity of the enzyme was inhibited at high glucose concentrations.An enzyme which catalyzes the conversion of d-glucose to d-fructose has been demonstrated in cell-free extracts of Streptomyces phaeochromo genus grown in the presence of D-xylose. The enzyme preparation reacts with d-glucose and d-xylose, but not with other sugars tested. It appears to require magnesium for the maximal activity and the addition of cobaltous ion remarkably intensifies the heat tolerance of the enzyme. The maximal activity occur...

Effects of Nitrogen Assimilation on the Fermentation Activity of Baker's Yeast. Part II

熟成を経たパン酵母に窒素を吸収させると遊離アミノ酸を再生し,蔗糖醗酵力が著しく増加するが,アミノ態窒素の再生は培地中の糖量に左右され,ある程度まで糖量の多いほど再生量も多くなる.菌体の炭水化物,窒素含量,核酸の分析から培地の糖量を規制することによりこれらの変化をある程度調節することができ,炭水化物の減少を僅少にとどめて窒素同化を行わせることによって酵母の耐久性についても好結果をえた.また耐久性に対する菌体の窒素含量の影響のうち,アミノ態窒素への考慮が必要であることを論じた.