Factors affecting the fermentative production of L-valine were studied and optimal conditions were determined in the shake flask production by Aerobacter aerogenes NISR-B-801. Optimal C/N-ratio, 100:7.8 (at 10% glucose), and adequate aeration, Kd. about 6.0×10-6 [gram-mole of oxygen per atm. min. cc of broth], were found to be the most important factors to bring about L-Valine fermentation. Chemical ingredients of media, especially trace elements (e.g., Ni, Mn, Mo) as well as bulk elements (phosphorus, Mg, K) have also remarkable influences on valine formation. The most efficient fermentation was performed with optimum inocula, 4-5 per cent(v/v) of media, under optimal pH 6.2-5.4. The high yields of L-valine, about 20 per cent conversion of glucose, were obtained under the conditions studied.
Applying P32, effects of fiber diameter, volume fraction, moisture content and dust loading on the bacterial distribution within air sterilization filter were studied experimentally. The experimental results were analysed and probability functions were derived. Using the probability functions, the relations between air filter life (collection efficiency) and the above-mentioned operating variables were made clear. The relations remain to be checked experimentally using a bacterial aerosol, the concentrations of which being those usually encountered in air sterilization practice.
Thiaminase II of Bacillus aneurinolyticus was purified and crystallized from the cultured synthetic medium by ammonium sulfate fractionation, calcium phosphate gel treatment and starch zone electrophoresis. Some of the properties of the purified enzyme were demonstrated.
In order to obtain microorganisms which produce lytic enzyme active against cell walls of Saccharomyces cerevisiae, samples collected from soil were spread on an agar medium containing heat-treated baker's yeast. In the initial screening, about 150 colonies which showed clear zones on the medium around them were selected. In the second test the lytic activity of the culture liquid of these isolates were measured by means of the cup-assay method. Among them eight strains of Streptomyces were found to be active and nine strains of bacteria active to a lesser extent. By means of the turbidimetric assay, the culture liquids of all eight strains of Streptomyces also exhibited lytic activity toward heat-treated cells of Saccharomyces cerevisiae in two hours incubation. Among the eight strains of Streptomyces, strain no. 62 was selected and studied further, because it showed the strongest lytic activity and produced the lytic factor for an extended time. The lytic factor produced by the strain was concentrated by ammonium sulfate precipitation. Living cells of Saccharomyces cerevisiae proved to be lysed by the concentrated lytic factor in short period.
The properties of the cell wall lytic enzyme produced by Streptomyces no. 62 strain were studied. The lytic enzyme had a optimal activity in the pH range from 7.2 to 8.0, with highest activity at 7.6, and appeared relatively thermolabile. Besides 17 kinds of yeasts including Willia anomala and Endomycesmagnusii, some fungi such as Aspergillus oryzae, Penicillium chrysogenum and Neurospora crassa were lysed by the lytic enzyme. Among the bacteria tested, only hemolytic group A Streptococcus and Micrococcus lysodeikticus were found to be sensitive to the enzyme. The cell walls of Saccharomyces cervisiae, isolated by mechanical disintegration, were lysed by the lytic enzyme. The "protoplast" of Saccharomycescerevisiae was formed by the lytic enzyme within thirty minutes incubation. It appears that the lytic enzyme solution is a mixture of enzymes since it has a strong protease activity, which, when arrested by an inhibitor, lyses the cell walls of yeast to a lesser extent than with uninhibited protease present.
(1) The sulfur-containing peptide-nucleotide compound(s), whose existence in the TCA-extract of Chlorella cells has been discovered previously, was separated from synchronously grown algal cells at different stages of their life cycle. As far as the electrophoretic experiments performed at pH 3.6 were concerned, the compound isolated at the stages of cellular ripening (stages of nuclear division) showed almost the same properties as that isolated from younger unripened cells. (2) When the algal cells were grown in a sulfur-deficient medium, the 1960 Some Data on the Nature of Sulfur-Containing Peptide-Nucleotide 67 TCA-extract prepared by the same procedure contained a nucleotide-complex, which, in the electrophoretic field, behaved almost in the same manner as the normal peptide-nucleotide complex, but, in sharp contrast to the latter, it contained neither sulfur nor the peptide-moiety. (3) Based on these findings and on the other data thus far obtained, it was inferred that the S-containing peptide-nucleotide complex found in normal cells may be an intermediate in the syntheses of nucleic acids and probably of some proteins, and that the peptide-free nucleotides found in S-starved cells may be a precursor or a remnant moiety of the former, which are incapable of being utilized in the syntheses of nucleic acids owing to the absence of the peptide-moiety.