枯草芽孢杆菌S-16抑菌活性物质的理化性质及培养条件的研究

Research on Antibacterial Properties and Culture Conditions of Bacillus subtillis S-16

枯草芽孢杆菌Bacillus subtilis S-16对向日葵菌核病有较好防治效果,本试验对其产生抑菌物质的理化性质进行了研究。结果表明,抑菌物质经20℃处理1 h后,抑菌效果最显著,抑菌圈直径最大,为1.72 cm(包含孔的直径0.70 cm),虽然随着温度的升高抑菌物质的活性在下降,但是经80℃处理1 h的抑菌物质仍有活性,抑菌圈直径为1.00 cm(包含孔的直径0.70 cm),说明该抑菌物质有热稳定性;且经过胰蛋白酶、胰凝乳蛋白酶、胃蛋白酶等3种蛋白酶对该抑菌物质进行处理后,菌株S-16产生的抑菌物质的抑菌活性无显著影响,说明该类抑菌物质对蛋白酶稳定;另外,经紫外灯照射30 min的抑菌圈直径为1.57 cm,对照的抑菌圈直径为1.85 cm,虽然抑菌活性下降,但抑菌物质仍有抑菌活性,进一步证明菌株S-16产生的抑菌物质为一种脂肽类物质。同时,试验提出了最利于菌株S-16产生抑菌物质的培养条件是以葡萄糖为碳源,以牛肉浸膏为氮源,40 m L(100 m L三角瓶)的装液量,p H为中性条件下,20~40℃培养。

We studied the physical and chemical properties of antibacterial material of Bacillus subtilis S-16, a good biocontrol agent of sunflower Sclerotinia rot. Results showed that the antibacterial material had a good effect under 20 ℃ for 1 h with inhibition zone 1.72 cm; the activity decreased with the increase of temperature, but still active under 80 ℃ for 1 h with inhibition zone 1.00 cm. The results showed that the antibacterial material was thermally stable. The antibacterial material was resistant against trypsin, chymotrypsin and pepsin treatments. Inhibition zone under ultraviolet irradiation and control were 1.57 cm and 1.85 cm respectively. These result demonstrated that the antibacterial material of S-16 was lipopeptide. The most conducive conditions to produce the antibacterial material were glucose as carbon source, beef extract as nitrogen source, neutral p H with 20—40 ℃ temperature.