Under optimum conditions, the unconcentrated filtrate of Trichodermaviride QM 9414 showed a considerable cellulolytic activity against newspaper yellow and cardboard which were preferentially attacked by the enzyme. The percentage conversion was 46.6 and 42.2 in 24hr, respectively. The alkali treatment resulted in increased degradation of sugar cane bagasse from 7 to 48.1% (24-hr treatment with enzyme) and to 70% (48-hr treatment with enzyme). The bagasse hydrolyzate was found by chromatography to contain mainly glucose, xylose, arabinose, cellobiose, and unidentified saccharides. The hydrolyzate, when enriched with urea and yeast extract, supported good growth of Saccharomyces cerevisiae, Candida tropicalis, Pseudomonas aeruginosa, Escherichia coli, Lactobacilluscasei, and Rhizobium meliloti.
In order to analyze the growth of Thiobacillus thiooxidans in the basal Starkey's medium supplemented with solid particles of sulfur, CS2 method was developed to measure the cells adhering to the sulfur particles; the cells were totally released from the sulfur particles into the liquid phase by shaking of the culture with carbon disulfide, so that the total amount of cells existing in the culture could be measured quantitatively. The growth of Thiobacillus thiooxidans was remarkably enhanced by the addition of a trace amount of heavy metal ions to the basal Starkey's medium. It was found that, at the initial phase of growth, practically all the cells were attached on the surface of sulfur particles and, with progress of the culture, an increasing number of cells appeared in the liquid phase. At the stationary phase of growth, about equal amounts of cells were distributed on the sulfur particles and in the liquid phase. Among the trace elements added, molybdate was found to be the very substance to accelerate the growth of Thiobacillus thiooxidans. In the presence of molybdate (below 0.3ppm as molybdenum) the specific growth rate and the final cell yield increased 2- and 4-fold, respectively, compared to those in its absence. This stimulative effect could not be substituted by tungstate, chromate, or vanadate.
Nuclear behavior in the cells of Rhodosporidium toruloides, a heterobasidiomycetous yeast, was followed by microscopic observation. The behavior in the process of both asexual and sexual reproduction of the microorganism was found to agree, in principle, with the description on that of Leucosporidium sp., a heterobasidiomycetous yeast. In the artificially induced sexual differentiation in the cells of mating type a strain by A factor (a sex hormone secreted from the cells of mating type A strain), a complete repression of nuclear division occurs with the induction of mating tube formation. As elongation of the tube proceeds, a nucleus moves into the tube from the cell, followed by further migration to the apex of the tube. In the process of artificially induced dedifferentiation by removal of the factor from the incubation medium, the nucleus which was located in the mating tube by previous incubation with the factor recovers the ability to divide into two nuclei without formation of clamp connection. Then the septum formation occurs, followed by emergence of a bud. The bud grows and matures to a yeast cell.
The effect of inoculum size and growth phases of seed cultures on main cultures was examined using a Biophotometer (Jouan, Paris). Lag time and L10, which is the time of reduction of lag time when inoculum size is increased 10 times, were influenced by growth phases of seed cultures. Two types were found in the change of lag time; in one, the length of lag time varied with the growth phase of seed culture, and, in the other, the length of lag time did not change by the growth phase of seed culture. Two types were also found in the change of L10; in one, L10, was influenced by the growth phase of seed culture, and, in the other, it was not affected by the growth phase of seed culture. From these results, the influence of growth phase of seed culture on lag time and L10 of main culture could not be concluded as a common principle. The significance of L10 was discussed from the effect of inoculum size and it was presumed that variable L10 was caused by the inoculum composed of cells with different growth rates.
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Edited and published by : Applied Microbiology, Molecular and Cellular Biosciences Research Foundation/Center for Academic Publications Japan Produced and listed by : TERRAPUB, Center for Academic Publications Japan/Shobi Printing Co., Ltd. (-Vol.60,No12), Center for Academic Publications Japan/InternationalAcademic Printing Co., Ltd.(-Vol.54,No1)