Study on Bacillus thuringiensis Fermentation Supernatant Antimicrobial Spectrum and Stability

Abstract:

Antibiotic effects and stability of bioactive substance from fermentation broth of Bacillus thuringiensis（BT）Bt185 and HD-1 were initially studied. Oxford plate was used to study the bacteriostatic effect of fermentation broth，tested for the bacteria Erwinia herbicola，Escherichia coli，Staphylococcus aureus，Bacillus subtilis，Bacillus cereus，Proteus bacteria，Corynebacterium glutami-cum， Bacillus paratyphosus B，Bacillus aeruginosus nine kinds of bacteria. The results showed that，the antimicrobial activity of Erwinia herbicola was better than other eight kinds of bacteria. Fermentation broth to heat，acid，ultraviolet radiation and continuous ultrasound stimulation were stable；the fermentation broth above 50 ℃ antibacterial activity began to decline，at a pH of 3.0~9.0 conditions antibacterial activity stability，within 2.5 h of UV irradiation stable antibacterial activity，within the continuous 360 W of ultrasonic condition 2 h antibacterial activity stability.