Hydroxylation of digitoxigenin with Absidia orchidis resulted in the formation of 1β-hydroxydigitoxigenin (=acovenosigenin A), 5β-hydroxydigitoxigenin (=periplogenin), 7β-hydroxydigitoxigenin, 1β, 7β-dihydroxydigitoxigenin and 5β, 7β-dihydroxydigitoxigenin. This is probably the first example of microbial 1β-hydroxylation of steroid.

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When Absidia orchidis, which under the conditions described in the preceding paper converted digitoxigenin mainly into 1β-hydroxydigitoxigenin, was grown in a medium containing 6% glucose, 1% peptone and 0.3% corn steep liquor and incubated with added digitoxigenin, 7β-hydroxydigitoxigenin was found to accumulate as a principal product. One of the factors affecting such changes in bioconversion make-up seems to be the selective inhibitory action of the substrate digitoxigenin on the microbial 1β-and 5β-hydroxylation reactions.

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The microbial activity to dehydrogenate 3-hydroxyl groups of cardenolides was found not to be affected greatly by the change in spatial arrangement of the hydroxyl group at C-3 or of the unsaturated lactone ring at C-17. Whereas 3-epidigitoxigenin resisted the microbial hydroxylation, 17α-periplogenin was isolated and identified on incubation of 17α-digitoxigenin with Absidia orchidis, thereby showing that the change in orientation of lactone ring at C-17 does not have a decisive effect on microbial hydroxylating activity.

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Purification of amylase produced by Endomyces sp. IFO 0111 was carried out. A highly purified amyloglucosidase preparation was obtained from culture broth by means of precipitation with ammonium sulfate, decolorization with rivanol, precipitation with acetone and zone electrophoresis. The homogeneity of the preparation was proved by ultracentrifugation and electrophoresis. General properties of the preparation were investigated.

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Synthesis of a new lactone of cyclohexane series, 3-methyl-cyclohexane-cis-diol-(2, 5)-carboxylic acid lactone, is described. Spectroscopic properties of this and another lactone as well as two related esters are listed.

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A synthesis of racemic 7-demethyldihydrogibberone, a tetracyclic ketone possessing the gibbane skeleton, is described. An attempted synthesis of racemic epidihydrogibberone via hydrofluorenones is also described.

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α-Hydroxyisobutyraldehyde, one of model compounds for α-aldol structure of streptose moiety of strpetomycin, was reduced at controlled-potential mercury cathode to give isobutyl alcohol and 1, 1-dimethylethyleneglycol. Reduction ratio of α-hydroxyl group was dependent on the cathode potential and pH, as was seen in the reduction of streptomycin. Results of reduction of α-hydroxyisobutyraldehyde with sodium or aluminum amalgam suggests that their mode of action on the aldehyde is determined by the magnitudes of negative potential that they respectively retain in the reaction media, and by pH, as in the cases of electroreduc-tion. Isobutyraldehyde was isolated as an intermediate product of reduction to isobutyl alcohol, in both cases.

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The behaviors of impurities such as amino acids and inorganic salts at the time of crystallization of L-glutamic acid were investigated; and it was concluded that amino acids which co-existed in the solution of L-glutamic acid followed the crystals of L-glutamic acid persistently, and the contamination mechanism would not be clarified by the adherence of mother liquor or the formation of liquid foams in the crystals, or by the mixed crystal forma-tion, but by a physical adsorption on the crystal surfaces.

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The structure of crude crystals of L-glutamic acid was conjectured from a phenomenon, the disintegration of the crude crystals when they were dipped in the saturated solution of L-glutamic acid of pH from 5 to 7, and from the measurement of the actual surface area on the crude crystals by means of determination of the adsorption equilibrium of humic acid; and it was considered that the crude crystals had a mosaic structure consisting of fine crystalets, for example those of size of about 1μ when the purity of crystals was about 97%.

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In connection with the behavior on hydrolysis of mucopolysaccharides, acid hydrolysisof methyl D-glucopyranosides, methyl 2-amino-2-deoxy-D-glucopyranosides (hydrochlorides aswell as N-substituted derivatives), and methyl D-glucuronides was carried out. The differencein hydrolysis rate of methyl 2-amino-2-deoxy-D-glucopyranosides was ascribable to that ofthe substituents on the amino group, whereas hydrolysis rate of methyl D-glucuronides wasdependent on their ring structures. The possible behaviors in acid hydrolysis of glycosidic linkages in mucopolysaccharides are discussed.

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