| Bacillus subtilis B25 is found to produce antimicrobial substance, which has exhibited significant inhibitory effect on Fusarium oxysporum. In the paper,the time of the antimicrobial substance produce, the stability of it on temperature, pH, two proteinases (trypsin, proteinaseK) and the activity with 10, 30, 50 ku ultrafiltration tube filtering were studied. The results showed that the antimicrobial substance not changed significantly even in 100益boil 1 hour; It tolerated acidic, neutral and slightly alkaline but was not stable in strong alkalie. With regard to the two proteinases,the activity decreased obviously when deal with trypsin and proteinaseK. It failed to pass 10尧30 ku filter membrane but can pass 50 ku. |
