Optimization of Bio-Mosquitocidal Production using Local Bacterial Strains of Bacillus Sphaericus

Abstract

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.