抗青霉芽孢杆菌的筛选及抑菌物质分析

从采自黑龙江齐齐哈尔、黑龙江大庆、辽宁沈阳等8 个地区的10 份自然发酵豆酱中分离出40 株芽孢杆菌，并采用平板对峙法和琼脂柱法筛选出2 株对青霉菌具有良好抑制作用的QQHE-2和DQ1-3菌株，其对青霉菌的抑菌率可达到83.42%和46.83%。经16S rRNA分子生物学鉴定两株菌为枯草芽孢杆菌。用扫描电镜观察发现，QQHE-2菌株发酵上清液使青霉菌菌丝形态发生改变，孢子形状干瘪且数量减少。通过对菌株发酵上清液进行pH值和温度调节及用蛋白酶处理，发现菌株分泌的抑菌物质的耐酸性和耐热性较差，经蛋白酶处理后对青霉菌的抑菌率显著降低，由此判断抑菌物质的有效成分为蛋白类或肽类物质。经十二烷基硫酸钠-聚丙烯酰胺凝胶电泳测定QQHE-2菌株产生抑菌物质的分子质量约为35 kDa。

Isolation and Identification of Anti-Penicillium Bacillus Inform Fermented Soybean Paste and Analysis of Antimicrobial Substance

A total of 40 strains of Bacillus were isolated from 10 naturally fermented soybean pastes from 8 regions in northeastern China, including Qiqihar, Daqing and Shenyang. Strains QQHE-2 and DQ1-3, with good inhibitory effects (83.42% and 46.83%, respectively) on Penicillium, were obtained by plate confrontation method and agar column method. The two strains were identified as Bacillus subtilis by 16S rRNA gene analysis. It was found by scanning electron microscopy (SEM) that the fermentation supernatant of QQHE-2 changed the morphology of Penicillium hyphae, making the spores become dry and winkled and reducing the number of spores. Upon pH and temperature adjustment and treatment of the fermentation supernatant with protease, it was found that the acid and heat resistance of the antimicrobial substance were poor, and the inhibition rate against Penicillium was significantly reduced by protease treatment. It can be confirmed that the antimicrobial activity was attributed to the presence of a protein or peptide. The molecular mass of the antimicrobial substance produced by QQHE-2 strain was about 35 kDa as revealed by sodium dodecyl sulfate-polyacrymyl gel electrophoresis (SDS-PAGE).