Takeji Mizunuma

Studies on the Metabolism of Aspergilli :Part IX. Effect of Water Level of Culture Medium on Metabolism of Organic Acids and Distribution of Enzymes between Mycelia and Medium

Using Aspergillus sojae K.S., studies were made on the effect of water level of culture medium on the metabolism of organic acids and on the distribution of protease and α-amylase between the mycelia and culture medium. The mold was grown on the media of various water levels made of powder of defatted soybean and wheat granule. Grown on the low water medium, the mold consumed much more organic acids especially citric acid in the medium. At the same time, the composition of organic acids in the mycelia were also affected by the water level of the medium. It was observed that much more protease and α-amylase were found in the medium than in the mycelia when the mold grew on the low water medium. It was shown that the mycelia grown on the low water medium were apt to release much more protease into the culture medium.

Studies on the Metabolism of Aspergilli: Part VIII. Relationship between Endogenous Formation of Ammonia and Levels of Mycelial Components

Studies were made on the relationship between endogenous formation of ammonia and levels of mycelial components of Aspergillus sojae K.S. It was found that levels of mycelial components such as total carbohydrates, glycogen, pool amino acids, protein, free nucleotides and nucleic acids and extent of endogenous formation of ammonia were affected remarkably by the compositions of culture medium. Levels of the mycelial components were also affected by preincubation with ammonium sulfate. Generally speaking, endogenous formation of ammonia was suppressed or less remarkable in the mycelia that contained much more total carbohydrates and glycogen, and less nitrogenous materials.

Studies on the Metabolism of Aspergilli: Part VII. Effect of Water Level of Culture Medium on Mycelial Compositions and Enzyme Production

Studies were made on the effect of water level of culture medium on the mycelial compositions and enzyme production in Aspergillus sojae K. S. The mold was grown on the media of various water levels made of powder of defatted soybean and wheat granule. The mycelia grown on the medium of low water level produced more protease and α-amylase, consumed more oxygen, formed less ammonia, and were richer in 2 n H2SO4-soluble glycogen, 60% H2SO4-soluble carbohydrates, protein and RNA per mg dry weight than the mycelia grown on the medium of high water level. Chromatographic analyses were carried out for nucleotides, sugar phosphates and free carbohydrates in cold TCA-soluble fraction of the mycelia.

Studies on the Metabolism of Aspergilli: Part IV Stimulation of Transaminase Formation by γ-Glutamic Hydrazide and Hydrazine

The formation of glutamate-alanine transaminase and glutamate-aspartate transaminase of Aspergillus sojae K.S. was stimulated by γ-glutamic hydrazide and hydrazine. This studies were concerned with the effects of culture medium composition (C/N), culture periods, amino acids and glucose, on the stimulation of the transaminase formation by these analogues. Ammonia formation from the mycelia was slightly increased by incubation with γ-glutamic hydrazide although oxygen uptake was suppressed. From suppressing effect of L-glutamine and various effects of ammonia, amino acids and glucose on the enzyme formation, it came to conclusion that L-glutamine or its derivative in the mycelia possibly regulates the formation of the transaminases.

Studies on the Metabolism of Aspergilli: Part V. Stimulation of Glutamic Dehydrogenease Formation by γ-Glutamic Hydrazide and Hydrazine

It was found that either γ-glutamic hydrazide or hydrazine at an appropriate concentration stimulated the formation of glutamic dehydrogenase as well as transaminases. Addition of l-glutamine partially reduced the stimulating effects of analogues.

Studies on the Metabolism of Aspergilli :Part I. Substrates of Endogenous Respiration

Endogenous respiration of Aspergillus sojae K.S. was studied in terms of biochemical analysis. It was found that the different kind of substrates was utilized for the endogenous respiratoin according to C:N ratio of the agar medium on which the mold was grown. In the mycelial mats grown on the medium of low C:N value, pool amino acids, protein, and nucleic acids were mainly utilized from the beginning while carbohydrate or lipid displayed a minor role. The corresponding amount of ammonia was formed. On the other hand, in the mycelial mats grown on the medium of rather high C:N value, carbohydrate or lipid was the major substrate of endogenous respiration in the early stages of incubation. The utilization of the nitrogenous materials and the accompanying formation of ammonia got to start only after the lapse of several hours of incubation.