Abstract:

Bacillus subtilis is a kind of beneficial microbes in biological control and fruit preservation currently. In order to explore the biocontrol effect and mechanism of Bacillus subtilis to litchi postharvest pathogenic fungi in Guangxi, experiments had been carried out to study the method of antifungal substances extraction from fermentation liquid, the partial physical and chemical properties of antifungal substances in Bacillus subtilis strain based on collection, separation, screening and identification. Antifungal substances of strain ON-6 with hydrochloric acid and ammonium sulfate both had inhibitant activity, showed that strain ON-6 were able to produce the proteins and lipopeptide antibiotics simultaneously. The inhibitant activity of crude antifungal protein produced by strain ON-6 was also stable when it was treated with 30~60℃ for 30 minutes, but was depressed less than 40% of the original with 121℃ for 20 minutes. Antifungal substances were partially sensitive to trypsin, and insensitive to proteinase K, pepsin and UV. The inhibitant activity pH rang of antifungal substances was from 5.0 to 8.0.