传统发酵豆瓣中产毒黄曲霉高效拮抗菌的筛选

从自然发酵的豆瓣中筛选出对产毒黄曲霉菌的生长及其毒素合成均有抑制作用的细菌, 在蚕豆天然培养基(BAM)上利用菌落对峙实验初筛和滤纸片复筛得到1株有较高抑制产毒黄曲霉活性的菌株L4。对L4进行形态学、生理生化特征及16S rRNA序列同源性分析, 鉴定此菌株为枯草芽孢杆菌(Bacillus subtilis)。在抑制黄曲霉生长和黄曲霉毒素B1 (AFB1)合成的研究中表明, 在L4与黄曲霉菌共同培养15 d后, 黄曲霉菌丝产量和黄曲霉毒素B1 产量均比黄曲霉单独培养时显著降低(P < 0.01), AFB1合成受到明显抑制, 抑制率达93.7%。当黄曲霉孢子液与L4发酵上清液1: 1 (V/V)混合后接种在玉米粒上时, 黄曲霉在玉米上的生长和孢子萌发均得到完全抑制。

Screening of Antagonistic Bacteria Against Aflatoxigenic Aspergillus flavus from Fermented Bean Paste

The mixture of broad bean and wheat flour during fermentation was used to screen antagonistic bacteria against aflatoxigenic Aspergillus flavus. A strain L4 with strong antifungal activity against the aflatoxin-producing Aspergillus flavus was selected using broadbean agar medium (BAM). According to its morphological, physiological and biochemical characteristics and 16S rRNA gene sequence homology analysis, L4 was identified as Bacillus subtilis. When L4 and Aspergillus flavus were co-cultured for 15 days, the weight of the mycelium and the production of aflatoxin B1 were both significantly lower than those of Aspergillus flavus cultured without L4. The accumulation of AFB1 was inhibited significantly, the values of the reduction was 93.7%. When L4 culture supernatant was mixed with the spore suspension of A. flavus at ratio of 1: 1 and then inoculated on corns, the germination and growth of A. flavus was inhibited completely.