Antifungal activity of 2 lactic acid bacteria of the Weissella genus isolated from food.
ABSTRACT 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 were Lactobacillus 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 for Lb. plantarum VE56 (0.56 mM). Hydroxy fatty acid, such as 2-hydroxy-4-methylpentanoic acid, was also produced and involved in the inhibitory activity of Lb. 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 from Weissella 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. PRACTICAL APPLICATION: Antifungal LAB are interesting to prevent food spoilage in fermented food and prolong their shelf life. In this way, chemical preservatives could be avoided and replaced by natural preservatives.
Article: Rapid identification, by use of the LTQ Orbitrap hybrid FT mass spectrometer, of antifungal compounds produced by lactic acid bacteria.[show abstract] [hide abstract]
ABSTRACT: Fungal contamination of food causes health and economic concerns. Several species of lactic acid bacteria (LAB) have antifungal activity which may inhibit food spoilage fungi. LAB have GRAS (generally recognised as safe) status, allowing them to be safely integrated into food systems as natural food preservatives. A method is described herein that enables rapid screening of LAB cultures for 25 known antifungal compounds associated with LAB. This is the first chromatographic method developed which enables the rapid identification of a wide range of antifungal compounds by a single method with a short analysis time (23 min). Chromatographic separation was achieved on a Phenomenex Gemini C18 100A column (150 mm × 2.0 mm; 5 μm) by use of a mobile-phase gradient prepared from (A) water containing acetic acid (0.1%) and (B) acetonitrile containing acetic acid (0.1%), at a flow rate of 0.3 µL min(-1). The gradient involved a progressive ramp from 10-95% acetonitrile over 13 min. The LC was coupled to a hybrid LTQ Orbitrap XL fourier-transform mass spectrometer (FTMS) operated in negative ionisation mode. High mass accuracy data (<3 ppm) obtained by use of high resolution (30,000 K) enabled unequivocal identification of the target compounds. This method allows comprehensive profiling and comparison of different LAB strains and is also capable of the identification of additional compounds produced by these bacteria.Analytical and Bioanalytical Chemistry 04/2012; 403(10):2983-95. · 3.78 Impact Factor