枯草芽孢杆菌R21-4的诱变育种及其抗菌蛋白性质的研究

Breeding of an anti-microbial bacillus strain and study on the anti-microbial protein from the strain

实验室筛选到的BacillussubtilisR21-4对某些革兰氏阳性、革兰氏阴性细菌及真菌均有抑制作用,为了进一步提高该菌株对食品中常见腐败菌大肠杆菌的抑菌效果,对枯草芽孢杆菌R21-4进行了自然选育、紫外诱变,从而筛选到一株抑菌活性有较大提高的稳定突变株Bacillussp.R21-15,其抗菌效价比原始菌株提高了58.49%。Bacillussp.R21-15的抗菌蛋白具有良好的热稳定性,对蛋白酶部分敏感。Tricine-SDS电泳初步显示出这一抗菌蛋白的分子量在6.4～7.2kDa之间。

Bacillus sp. R21 -4 demonstrated a broad spectrum of anti-microbial activity against some Gram-negative bacteria, Gram-positive bacteria, and some fungi. To obtain highly antimicrobial stra）n against the food-borne Escherichia coli, Bacillus sp. R21-4 was treated with spontaneous screening and then by UV mutagenesis. A stable strain was obtained with the antimicrobial titer increased by 58.49% than the parent strain. Direct detection of antimicrobial activity on Tricine-SDS suggested that the anti-microbial protein has a molecular mass of the protein about 6400Da-N7200Da.