黑曲霉抗产毒黄曲霉作用的初步研究

采用90 × 2.6 × 1013N+/cm2 注入黑曲霉筛选能抗黄曲霉(Aflavus)生长的突变菌株，以利发酵中控制被黄曲霉污染的原材料的再污染。进行产毒黄曲霉与被离子注入的黑曲霉混合对峙、原黑曲霉菌株与黄曲霉单独培养生长及混合对峙培养实验。结果显示经离子注入的菌株及未注入菌株均对黄曲霉产生抑制作用，但后者仅有微弱抑制，前者不仅表现出几乎不能使黄曲霉生长，且已长出的黄曲霉菌丝体较瘦小，并呈灰白色。从培养基中提取物检验结果显示，黄曲霉组表现出有较明显的荧光反应，而黑曲霉菌株对峙培养物提取物中有微弱的荧光反应，其黑曲霉突变株对峙培养物未见荧光反应检出。这表明黑曲霉原菌株虽然能对黄曲霉只有微弱抑制，但表现出黄曲霉产毒和合成色素能力下降。与对照组相比，突变株有较强抑制黄曲霉生长能力。

Preliminary Study on Antagonistic Effect of Aspergillus niger Mutant against Aspergillus flavus TO

Aflatoxin produced by Aspergillus flavus TO has strong carcinogenesis. Aspergillus niger mutant, resulted from original Aspergillus niger infiltrated with N+ ion beams at dose of 90×2.6×1013 N+/cm2, was selected to suppress growth of Aspergillus flavus TO and favored to be applied in control of a secondly possible contamination in Aspergillus flavus-contaminated raw materials in ferment industry. Based on such experiments as cultivation of Aspergillus flavus TO and N+-infiltrated Aspergillus niger strains together, and cultivation of Aspergillus niger and Aspergillus flavus TO strains alone and together, the results showed that Aspergillus flavus TO strains are inhibited by both Aspergillus niger and N+-infiltrated Aspergillus niger strains, and the inhibition in the former is slight but that in the latter is almost complete. In addition, grey and slim mycelia in Aspergillus flavus TO strains are also shown in the cultivation together with N+-infiltrated Aspergillus niger strains. Moreover, extracts from media were also examined by aflatoxin fluorescence analysis. Relatively obvious signals are observed in the Aspergillus flavus TO group, faint signals in the Aspergillus niger group, but no signals in the N+-infiltrated Aspergillus niger strain group. In conclusion, the original Aspergillus niger strain exerts slight inhibition against Aspergillus flavus TO growth and makes the decline in synthesis of aflatoxin and related pigments, while the Aspergillus niger mutant strain shows significant inhibition against the growth of Aspergillus flavus TO strain compared with the control. Therefore, the Aspergillus niger mutant strain has the potential be introduced to alcohol industry to prevent from Aspergillus flavus TO contamination and ensure safety in the ferment ation process.