解淀粉芽孢杆菌TF28抗菌粗蛋白的初步研究

解淀粉芽孢杆菌TF28是从大豆根部分离得到的一株具有广谱高效拮抗作用的内生细菌，其发酵上清液经20％～40％硫酸铵盐析后获得抗菌粗蛋白。为明确该粗蛋白的理化性质，研究了温度、pH值、UV照射和蛋白酶对其稳定性的影响。结果表明：该粗蛋白具有一定的热稳定性，100℃处理30rain后抑茵活性仍为原有抑菌活性的85．9％；且在较广pH（3～11）范围内比较稳定，活性均能保持在95％以上；对紫外线、胰蛋白酶不敏感，对蛋白酶K具有一定的耐受性。初步研究了抗茵粗蛋白的抑菌作用，结果显示，对所测定的12种病原真菌均有抑制作用，其中对大豆根腐病菌和水稻恶苗病菌的抑制作用尤为明显。其对水稻恶苗病菌病原茵孢子的萌发起到抑制作用，有效抑制中浓度（EC50）为138．32μg／mL。此外，该抗茵粗蛋白能破坏病原茵菌丝结构导致畸形。

Antifungal Crude Protein Produced by Bacillus amyloliquefaciens Strain TF28

Bacillus amyloliquefaciens TF28 is an endophytic bacteria isolated from soybean root that possesses high-performance antifungal abilities. The antifungal crude protein was got via 20 %-40 % ammonium sulfate precipitation. The influence of temperature, pH, UV and protease on the stability was studied to clarify the physicochemical properties of the crude protein. The results showed that the crude protein had certain thermal stability whose antifungal activity retained 85.9 % after at 100 o^C for 30min. The activities were relatively stable in wider pH （3-11） range that all retained 95% and it Was not sensitive to UV, trypsin and proteinase K. The inhibition of the crude protein was studied and the results showed that the crude protein inhibited all the twelve pathogenic fungi, and the inhibitory effect on Fusarium oxysporum f. sp. vedolens and Fusarium moniliforrne was more obvious than others. It can inhibit the germination of spores of Fusariurn moniliforme, and its EC50 is 138.32μg/mL. In addition, the antifungal crude protein could destroy the hyphal structure of pathogens and even cause them abnormal.