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

摘要：

枯草芽孢杆菌CAB-1是一株对番茄灰霉病有显著防效的生防菌株,抑菌蛋白是其产生的主要抑菌物质之一。研究表明,菌株CAB-1产生抑菌蛋白的最佳培养条件为：接种量2%,培养温度30℃,转速180 r/min,装液量100 mL/250 mL,培养时间48 h。考马斯亮蓝法测得最佳培养条件下菌株CAB-1产生的粗蛋白浓度为0.16 mg/mL。该粗蛋白对胰蛋白酶及蛋白酶K不敏感,胃蛋白酶处理使其活性降低14%；抑菌蛋白在100℃以下处理30 min活性变化差异不显著,而121℃处理30 min其抑菌活性为对照的72%。抑菌蛋白对酸碱的耐受范围广,在pH值3~12的范围内抑菌活性均能保持在75%以上,pH值2时抑菌活性降低为对照的59%。经甲醇、氯仿、乙醚、乙酸乙酯及丙酮处理后该粗蛋白的抑菌活性变化不大。

关键词: 枯草芽孢杆菌;抑菌蛋白;培养条件;稳定性