Antifungal Activity of 2 Lactic Acid Bacteria of theWeissellaGenus Isolated from Food
Dora Ndagano, Thibaut Lamoureux, Carine Dortu, Sophie Vandermoten, Philippe Thonart
Walloon Centre for Industrial Biology, Microbial Technology Unit, Univ. of Liège, Bd du Rectorat, 29-B.40, Liège B-4000, Belgium.
In the present study, a total of 116 lactic acid bacteria (LAB) strains isolated from Mill flour and fermented cassava were screened for their antifungal activity. Three strains among 116 were selected for their strongest inhibitory activity against food molds. These 3 strains wereLactobacillus plantarum VE56, Weissella cibaria FMF4B16, and W. paramesenteroides LC11. The compounds responsible for the antifungal activity were investigated. The strains displayed an inhibitory activity against targeted molds at acidic pH. However, the influence of organic acids was rejected according to the calculated minimal inhibitory concentration (MIC). Antifungal compounds were investigated in the cell-free supernatants and phenyllactic acid (PLA) was detected in different amounts with a maximal concentration forLb. plantarumVE56 (0.56 mM). Hydroxy fatty acid, such as 2-hydroxy-4-methylpentanoic acid, was also produced and involved in the inhibitory activity ofLb. plantarum VE56 and W. paramesenteroides LC11. Antifungal LAB are known to produce PLA and 3-hydroxy fatty acids and other organic acids with antifungal activity. This short communication focuses on antifungal activity fromWeissella genus. The antifungal activity was attributed to antifungal compounds identified such as PLA, 2-hydroxy-4-methylpentanoic acid, and other organic acids. Nevertheless, the concentration produced in the cell-free supernatant was too low to compare to their MIC, suggesting that the inhibitory activity was caused by a synergy of these different compounds.