链霉菌SG17代谢产物对玉米黄曲霉的抑制作用及其稳定性分析

Inhibitory Effect and Stability Analysis of Streptomyces SG17 Metabolites Against Aspergillus Flavus in Corns

黄曲霉是玉米贮存过程中主要的污染之一,直接影响食品以及饲料的品质和安全。利用微生物及其代谢产物进行生物防治具有广泛的应用价值。作者以前期筛选获得的SG17菌株为材料,通过形态学观察、生理生化检测及16S rRNA序列分析,初步确定为链霉菌;平板对峙实验显示该菌株能够显著抑制黄曲霉等多种病原真菌的生长,具有一定的广谱性;进一步提取SG17的抑菌粗提物100℃处理60 min,抑菌率为(41.24±0.32)%,与对照组相比降低了16%;室温条件下放置15 d的抑菌率为(25.95±0.68)%,仍保留约50%的活性,具有较好的热稳定性和环境适应性;50μg/mL的抑菌粗提物可以有效抑制黄曲霉孢子的萌发,100μg/mL的抑菌粗提物能够显著抑制玉米黄曲霉菌的生长,且继续培养至14 d,抑菌率仍保持80%以上,具有较高的应用价值。

Aspergillus flavus is one of the main contaminants in corns during storage,which directly affects the quality and safety of food and feed.The biological control by microorganisms and their metabolites has a wide range of practical application value.In this study,the SG17 strain obtained from previous screening was preliminarily identified as Streptomyces sp.strain through morphological observation,physiological and biochemical detection,and 16S rRNA sequence analysis.The dural culture method showed that this strain had a broad-spectrum antibacterial effect on various pathogenic fungi such as Aspergillus flavus.The inhibition rate of SG17 was(41.24±0.32)%when the crude extracts were further treated at 100℃for 60 min,decreasing by 16%compared with that of the control group.After 15 days storage at room temperature,the antibacterial rate was(25.95±0.68)%and retained about 50%activity,showing good thermal stability and environmental adaptability.The germination of Aspergillus flavus spores could be effectively inhibited by 50μg/mL of antibacterial crude extract.Furthermore,the growth of Aspergillus flavus on corns could be significantly inhibited by 100μg/mL antibacterial crude extract,and the antifungal rate remained above 80%after 14 days of continuous culture,which suggested high application value.