关键词: 枯草芽孢杆菌;抑菌蛋白;培养条件;稳定性

Abstract:

Bacillus subtilis strain CAB-1 exhibited an effective inhibitory activity against Botrytis cinerea, which caused tomato gray mold, and the antifungal protein produced by it was the major active compound against Botrytis cinerea.  In this paper, the results showed the optimum culture condition was 2% inoculums volume, 100 mL loading amount in a 250 mL flask, at 30℃ for 48 h on a rotary orbital shaker with 180 r/min speed. The concentration of the crude protein was 0.16 mg/mL by Bradford method. Crude protein produced by strain CAB-1 was not sensitive to Trypsin and Proteinase K, while the antifungal activity was reduced 14% by Pepsin. The crude protein showed stable activity at 100℃, and retained 72% antifungal activity at 121℃ for 30 min. The antifungal activity of crude protein kept stable over a wide pH value, which could contain above 75% at pH 3~12 and decreas to 59% of control at pH 2. The antifungal activity maintained in organic solvents such as methanol, chloroform, ethyl, ethyl acetate and acetone.

Key words: Bacillus subtilis, antifungal protein, culture condition, stability