| Popis: |
Highly active local strains of B. sphaericus were used along with the reference strains 1593 and 2297 to optimize the biocide production. The optimum conditions were as follow: 20% of total flask volume, pH 7.0,inoculum size 3-5×104 cfu / ml, 30° C and 200 rpm/5 days. Glycerol was the best C source at 0.5%; a greatsuppression up to >80% with propionic acid. All tested strains failed to synthesize biocide in the presence of inorganic N as a sole source; beef extract gave the supreme yield. Mg2+ was necessary for maximal productivity;however, Ca2+ damaged the fermentation. The uppermost productivity was achieved from 25 g/l fodder yeast, 500 ml/l corn steep liquor and 0.3 g/l MgSO4 as a medium. Chicken feather at 30 g/l proved to be an excellent monocomponent; a superlative improvement was achieved when feather (3.0%) supplemented with 0.03% of MgSO4. |
