为了从菌株ASR-12发酵液中分离纯化获得抗菌蛋白。将菌株ASR-12发酵液经硫酸铵沉淀、透析除盐后获得粗蛋白，粗蛋白进行热处理和Q Sepharose Fast Flow 柱层析，纯化后的蛋白进一步进行LC-MS鉴定，并克隆其编码基因进行测序。粗蛋白经热处理和柱层析后得到5个吸收峰，活性检测结果显示峰Ⅳ具有较高抑菌活性，经SDS-PAGE检测显示为单一条带，分子量约为50 kDa。LC-MS鉴定结果显示抗菌蛋白与M42家族肽酶同源性最高，覆盖度达到80%；并能从菌株ASR-12基因组中克隆到M42家族肽酶编码基因，测序结果经BLAST比对与解淀粉芽孢杆菌B9601-Y2的M42家族肽酶编码基因同源性达100%。菌株ASR-12产生的抗菌蛋白中，M42家族肽酶为主要活性成分。
In order to isolate and purify the antibacterial protein from fermentation broth of Bacillus amyloliquefaciens ASR-12. Fermentation broth from strain ASR-12 was precipitated with ammonium sulfate and desalted by dialysis to obtain the crude protein. The crude protein was subjected to heat treatment and Q Sepharose Fast Flow column chromatography. The purified protein was further identified by LC-MS and its coding gene was cloned for sequencing. 5 absorption peaks were obtained after heat treatment and column chromatography, and active detection results showed that the peak Ⅳ has a higher antagonistic activity, which displayed a single band with about 50 KDa by SDS-PAGE detection.The results of LC-MS identification showed that the antibacterial protein had the highest homology with M42 family peptidase and the coverage reached 80%. The gene encoding M42 family peptidase was cloned from the genome of strain ASR-12. The sequencing results after BLAST alignment showed that their homology reached 100% comparing with M42 family peptidase encoding gene from bacillus amyloliquefaciens B9601-Y2. M42 family peptidase is the main active component in the antibacterial protein produced by strain ASR-12.