拮抗链霉菌S24 发酵培养基的优化及其对黄曲霉的抑菌作用

Medium optimization for antagonistic Streptomyces S24 and its inhibition on Aspergillus flavus

摘要:

拮抗链霉菌S24 对黄曲霉、赭曲霉、黑曲霉等粮食和饲料中常见的曲霉菌具有广谱抗性。优化了该菌株抗菌物质高产发酵培养基配方，并分析该菌株产生的抗真菌物质对黄曲霉的抑菌作用。通过单次单因子试验、正交试验，对S24 菌株抗菌物质的发酵培养基进行了优化，利用显微镜观察，研究了S24 菌株产生的抗菌物质对黄曲霉菌丝及孢子的抑制作用。获得适合S24 菌株抗菌物质产生的最佳培养基配方为：淀粉10 g、葡萄糖40 g、黄豆饼粉24 g、酵母浸膏粉8 g、KH₂PO₄ 4 g、C

Abstract:

Streptomyces S24 has broad spectrum against Aspergillus spp. in food and feed, such as Aspergillus flavus, Aspergillus niger and Asperegillus alutacells. The objective of this study was to improve the production of antifungal substances produced by S24 and to test their inhibitory effects on Aspergillus flavus. By using one-factor-at-a-time experiment and orthogonal design method, we optimized the fermentation medium. The composition of an optimized medium for the production of antifungal substances contained (g/L): starch soluble, 10; Glucose, 40; yeast extract, 8; soybean powder, 24; KH₂PO₄ 4; and CaCO₃ 0.8. As a result, the productivity of antifungal substances could reach to 10 235.45μg/mL, and this value was 2.81 times higher than that of initial medium before optimization. Additionally, inhibitory effects of the products on Aspergillus flavus were analyzed. Antagonistic tests indicated that the antifungal substances greatly inhibited mycelium growth and spores germination of Aspergillus flavus. We observed through microscope that the mycelia grew abnormally, such as contorting, bulging, vacuole increasing and the cytoplasmic contents inside effusing and the spores appeared unusual, such as gathering, deforming, cytoplasmic contents inside effusing and fracturing.