Seigo Takasawa

Induction and production of cellulases by l-sorbose in Trichoderma reesei

SummaryCellulase production in Trichoderma reesei mutants was induced by l-sorbose, known to be an inhibitor of β-1,3-glucan synthesis. In the experiments the washed mycelia were used as resting cells. For CMCase induction over 24 h using T. reesei PC-3-7, the most effective pH, temperature and l-sorbose concentration were 2.8, 28° C and 0.3 mg/ml, respectively. Comparison with other cellulase inducers showed that the inductive level of CMCase by l-sorbose was similar to that by sophorose, known to be the most potent inducer of cellulases. Since the induction of CMCase was inhibited completely by 10 μg of cycloheximide per ml, the induction process was considered to involve de novo synthesis. Although l-sorbose had the effective inducibility of CMCase, the assimilation rate of l-sorbose was very low in T. reesei PC-3-7.

Production of cellulases from alkali-treated bagasse in Trichoderma reesei.

SummaryMost of the mutants of Trichoderma reesei had good cellulase productivity on Avicel but this was low on alkali-treated bagasse, which could be a most promising cellulosic biomass to use as an inexpensive carbon source for cellulase production. Two T. reesei mutants, PC-3-7 and X-31, in which strong cellulase activity is inducible by l-sorbose, were, however, found to produce cellulase on alkali-treated bagasse. They produced about 100 units of CMCase per ml in 5-1 jar fermentor culture with 4% alkali-treated bagasse as carbon source. They also showed higher cellulase productivity than other mutants on other easily saccharified substrates, such as alkali-treated rice straw and Walseths cellulose.

Studies on Biosynthesis on Biotin by Microorganisms: Part I. Accumulation of Biotin-Vitamers by Various MicroorganismsPart II. Identification of Biotin-Vitamers Accumulated by Various Microorganisms

The accumulation of biotin-vitamers in the culture media of a large number of microorganisms (about 700 strains) was studied. The contents of the biotin-vitamers were quantitatively determined by microbiological assays with Lactobacillus arabinosus and Saccharomyces cerevisiae.It was found that large amounts of biotin-vitamers were accumulated by various microorganisms such as Streptomyces, molds and bacteria, and that the yield of biotin-vitamers was enhanced by the addition of pimelic acid or azelaic acid to the media. It was also found that the main portion of the vitamers accumulated by many microorganisms did not support the growth of Lactobacillus arabinosus, while it did support that of Saccharomyces cerevisiae. The small amounts of true biotin were observed in the culture media of various Streptomyces and molds, but hardly in the culture media of bacteria.The identification of biotin-vitamers accumulated by various microorganisms is described, and the distribution of the vitamers in microorganisms...