ABSTRACT
Bacillus thuringiensis subsp. aizawai (HD133) was grown in culture media in which dextrose was a common carbon source and 30 different agricultural products and by-products were tested as the main nitrogen sources. These products included legumes, cereals, animal proteins, leaf proteins, yeasts, oilseeds, tubers, and casamino acid. Of the 30 products tested, cottonseed meal, defatted soy flour, and corn gluten meal were the most efficient substrates for the production of spore-crystal biomass and endotoxin potency. The carbohydrate/nitrogen ratios for these additives ranged from 0.3 to 0.5 and the glutamic acid content of their proteins from 9.2 to 16.0%. There was no close relationship between the estimates of the amounts of endotoxin produced and the potency of the product when fed to bertha armyworm, Mamestra configurata.
