Some factors influencing the production of certain biosynthetic penicillins.
نویسنده
چکیده
Basic media. (a) Natural. A medium containing 4 per cent corn steep solids, 4 per cent lactose, 1.5 per cent Cerelosel (92 per cent glucose) and 0.0044 per cent ZnSO4-7H20 was prepared in 95 per cent of the final volume. After adjustment to pH 5.6 to 5.8, it was sterilized by autoclaving. A suspension (20 per cent) of calcium carbonate was autoclaved separately. The calcium carbonate suspension was added to the broth to a final concentration of 1 per cent. The addition was made at the time of inoculation. As antifoam agent, soya bean oil or lard oil was added as indicated below. (b) Chemically defined. A medium of known composition was prepared using the concentrations of ammonium acetate, ammonium lactate, and inorganic salts reported by Jarvis and Johnson (1947). To obtain maximum yields with the strains of Penicillium used, it was found necessary to increase the concentration of lactose to 4 per cent and of Cerelose to 1 per cent. Moreover, to maintain suitable pH levels during fermentation, 0.8 per cent calcium carbonate was added. The antifoam agent used will be indicated in the experiments described below. Strains of Penicillium chrysogenuam. A number of mutants of P. chrysogenum Q176 were developed in our Laboratories by Farrell (1953). Several of these were shown to possess marked penicillin X-producing properties. In the experiments to be reported, one of these, UV15, was used. It was added as a spore suspension prepared in Foster sporulation broth (Foster et al., 1945). The ratio of spore suspension was kept constant at 2.5 ml per 100 ml of fermentation medium. Incubation and containers. The medium was distributed in 1-L Erlenmeyer flasks. These were incubated on a rotary shaker at 270 complete cycles per min. The temperature of the incubator was approximately 26 C.
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عنوان ژورنال:
- Applied microbiology
دوره 5 6 شماره
صفحات -
تاریخ انتشار 1957