Oxidizability of progesterone was examined with 284 strains of Rhizopus sp. preserved in this Institute. Among these, 21 strains were found to have such ability. Mass culture of five of these strains was carried out and the oxidation product was identified as 11α-hydroxyprogesterone. The yield obtained was approximately 50%, using Rh. Chinensis SAITO 10-10.
1. Comparative experiments were carried out in order for the purpose of examining the ability of 473 strains of Aspergillus fungi to form 11α- hydroxy- and 6β, 11α-dihydroxyprogesterone from progesterone. It was thereby found that the strains of black Aspergillus and their mutants had stronger oxygenation ability. 2. In order to increase the rate of oxygenation, examinations were made carried out on various cultural conditions and optimal conditions were selected. 3. Mass culture indicated that the fungi could be classified into strains producing only 11α-hydroxyprogesterone (A. usamii mut. shirousamii IAM B-407, A. awamori IAM K-0625) and strains that produced both 11α-hydroxy- and 6β, 11α-dihydroxyprogesterones (A. saitoi IAM R-1216, A. usamii U.V. mutant IAM 59-1). However, none of these fungi seemed to produce any other products. 4. Tank culture of A. saitoi IAM R-1216 was found to effect the complete oxygenation of the substrate in within 48 hours.
Syncephalastrum sp. was found to be capable of oxidizing progesterone to form dihydroxyprogesterone requiring a short period of incubation while trihydroxyprogesterone required a long period. These results indicated that steroids are able to be hydroxylated to trihydroxy compounds by one microorganism. The best result in oxidation was obtained by the addition of 100mg of progesterone to 100ml of the medium, dissolved in 2ml of methanol.
(1) For the purpose to obtain microorganisms having high dextran producing ability, five strains were isolated from various sources. These were lactic acid bacteria which were able to produce slime from sucrose. (2) Morphological and physiological investigations of these strains were carried out and a gummy material obtained from sucrose was identified as dextran. These strains were decided to be assigned to Leuconostocmesenteroides. (3) Dextran production by these strains was examined and it was confirmed that strain N-4 was the most satisfactory strain. Optimum conditions for dextran formation with this strain are as follows: (a) Optimum pH ranged between 6.8 and 7.4. (b) Peptone concentrations of 0.05-O.1% were optimum for the production of dextran. (c) A high yield of dextran production was obtained in low sucrose concentrations, and this decreased in a concentration of more than 15% sucrose. About 10% sucrose concentration was considerded to be suitable for dextran production. (d) K2HPO4 0.1% and NaCl 0.1% were found to be optimum for dextran production. (e) The use of yeast extract was very effective and fermentation was completed within 24-48 hours using a 0.05% concentration. (f) The production of dextran by shaking culture was found to be inferior to stationary culture. (4) Dextran fermentation was carried out in a large scale using a 200L fermentor. (a) The viscosity of the broth reached a maximum after 24 hours then decreased rapidly. (b) pH showed 4.4 after 24 hours then lowered slowly to 3.7 and maintained this value throughout the fermentation. (c) Total acid increased rapidly up to 48 hours, and then a slight increase was observed. (d) Dextran formation reached a maximum during 24-30 hours' incubation and the yield showing about 42.5% of sucrose. (e) Reducing sugars were produced in proportion to dextran formation, and a slight decrease was observed after it reached a maximum during 24-30 hours. (f) Fractional precipitation of native dextran which were obtained from both the 24 hours' and 7 days' culture broth respectively, was performed and it was found that the molecule of native dextran separated from the latter was lower than that of the former, so dextran once produced seemed to degraded by prolonged incubation.
(1) By using the technique of synchronous culture of Chlorella, the changes in contents of potassium, magnesium and iron in successive developmental stages of algal cells were investigated. (2) In percent of dry weight of cells, the content of potassium remained relatively constant throughout the life cycle, whereas the contents of magnesium and iron were lower at the growing stages (from the stage of "nascent dark cells" to the stage of "immature light cells") and higher at the ripening stage (the stages of light cells). (3) A brief discussion was made in an attempt to relate the data obtained with earlier observations regarding the changes in contents of various other cell materials in the life cycle of Chlorella cells.
In investigating the causes of deterioration of cereal grains under the influences of microorganisms, the author has held the view that the most important approach is to trace the movements of microflora in an ecological heterogenous system, termed cereal grain. Such microbiological studies on the cause of deteriorated rice, have been carried out in the same light. Results of this investigation are summarized as follows. (1) From a standpoint of microbiology, rice will be stored in unhusked form, which affords far more safety than in the polished form in Burma. (2) In regard of the movements of microflora during the storage period of unhusked rice in Burma, new crop rice gives very few Aspergillus and Penicillium and many so-called Yellow Pseudomonas, i.e: Pseudomonas lacnogenes, P. perlurida, P. xanthe, P. myxogenes, etc. however, in normal rice after it is stored during raining season in the form of unhusked rice, the number of Aspergillus, i.e: white Aspergillus, A. versicolor, A, fumigatus, A. glaucus group, etc. Penicillium, i.e; P. citrinum, P. notatum, P. oxalicum, P. commune, P. cyclopium, P. islandcium, P. rugulosum, P. chrysogenum, etc. and Streptomyces increase. (3) There is some rice of which deterioration can be recognized by visual inspection. The common feature of this deteriorated rice is that considerably more amounts of Aspergillus, Penicillium and Streptomyces are contained than in normal rice. (4) Up to the present no attention has been paid to Streptomyces found in rice. However, from the author's investigations many of these were found in almost every specimen of normal rice. Furthermore, these Streptomyces of rice mainly consist of S. diastaticus, S. leben, Stessel and Keitt, S. carifornicus, S. albus, S. intermedium etc. It was further found that some of these Streptomyces possesses a considerably poisonous function when mice were fed with food containing rice with any one of these strains grown on.
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