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

Abstract

The antifungal effect of metabolites produced by a new strain of Lactiplantibacillus (Lpb.) plantarum LPP703, isolated from naturally fermented yak yogurt, was investigated. The results showed that Lpb. plantarum LPP703 significantly inhibited four fungal species, including Penicillium sp., Rhizopus delemar, Aspergillus flavus, and Aspergillus niger. The metabolites produced after 20 h of Lpb. plantarum LPP703 fermentation showed the highest antifungal activity against Penicillium sp. Compared with the control group, the Lpb. plantarum LPP703 metabolites-treated Penicillium 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 Lpb. plantarum LPP703 metabolites on Penicillium 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 Lpb. plantarum 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 Lpb. plantarum, LPP703, had potent antifungal activity against Penicillium sp., which might be associated with the damage of the active ingredient to fungal membrane integrity. This study indicated that Lpb. plantarum LPP703 and its metabolites might act as biological control agents to prevent fungal growth in the food industry.

Relationship between the Physiological Activity of Japanese Post-Fermented Teas and Lactic Acid Bacteria

“…L. plantarum produces antifungal substances active against molds, including Aspergillus sp. [39,40]. Although the antifungal activity of lactic acid bacteria in Japanese post-fermented tea has not yet been investigated, it may contribute to the selection and control of fungi in post-fermented tea.…”

Yak Milk: Nutritional Value, Functional Activity, and Current Applications

“…Yak milk contains a variety of microorganisms that are beneficial to human health [98]. Studies have found that beneficial bacteria isolated and identified from yak yogurt have multiple functional activities, such as antibacterial [63,99], blood glucose regulation [100], weight loss and lipid-lowering effects [101], and improving gastric ulcers [102]. However, currently, yak yogurt is limited to household production without fixed production standards and has a short shelf life, which makes large-scale production impossible [103,104].…”