Abstract: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 50 μg/mL of antibacterial crude extract. Furthermore, the growth of Aspergillus flavus on corns could be significantly inhibited by 100 μg/mL antibacterial crude extract, and the antifungal rate remained above 80% after 14 days of continuous culture, which suggested high application value.
