Antifungal Effect of Metabolites from a New Strain LPP703 Isolated from Naturally Fermented Yak Yogurt.

The antifungal effect of metabolites produced by a new strain of LPP703, isolated from naturally fermented yak yogurt, was investigated. The results showed that LPP703 significantly inhibited four fungal species, including sp., , , and . The metabolites produced after 20 h of LPP703 fermentation showed the highest antifungal activity against sp. Compared with the control group, the LPP703 metabolites-treated sp. spores were stained red by propidium iodide, indicating that the cell membrane of the fungal spores was damaged. Moreover, the antifungal effect of the LPP703 metabolites on sp. was not changed after heating or treatment with various proteases, but showed a sharp decrease when the pH value was regulated to 5.0 or above. The oleamide, trans-cinnamic acid, and citric acid were the three most abundant in the LPP703 metabolites. Molecular docking predicated that the oleamide interacted with the active site of lanosterol 14-alpha-demethylase (CYP51, a crucial enzyme for fungal membrane integrity) through hydrogen bonds and had the lowest docking score, representing the strongest binding affinity to CYP51. Taken together, the metabolites from a new strain of , LPP703, had potent antifungal activity against sp., which might be associated with the damage of the active ingredient to fungal membrane integrity. This study indicated that LPP703 and its metabolites might act as biological control agents to prevent fungal growth in the food industry.