| 摘要 |
1501563 Microbial insecticides CRC COMPAGNIA DI RICERCA CHIMICA SA 19 May 1976 20740/76 Heading A5E [Also in Division C6] In cultivating Bacillus thuringiensis or a related Bacillus in submerged culture with aeration to produce a microbial insecticide product containing spores of the Bacillus and crystalline endotoxin, early lysis of the cells otherwise caused by the aeration during the submerged cultivation before the end of spore formation is prevented by either or both of the following adjustments: (1) discontinuing aeration and temporarily carrying out the cultivation under anaerobic conditions e.g. for 3 to 6 hours from the twelth hour of cultivation, and (2) maintaining the pH of the culture medium in the range 6.3 to 7.0. The spore formation, with the liberation of endotoxin crystals is complete after 35 to 40 hours cultivation. The microbial insecticide product is freed from toxic, water-soluble exotoxin by dialysis and is then dried by conventional procedures (specified). Bentonite clay may be introduced into the product before the drying. The dehydrated product may be comminuted, if necessary.
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