Antifungal activity of selected lactic acid bacteria from olive drupes

Abstract

AbstractIn this study, 16 Lactobacilli (LABs) isolated from the drupes of olive (Olea europaea) oil varieties were identified asLactiplantibacillus plantarum(seven isolates),Pediococcus pentosaceus(six isolates),Enterococcus faecium(two isolates) andStreptococcus salivarius(a single isolate) by peptide mass fingerprinting and sequencing of the 16S rRNA. Antifungal activity of LABs and their cell-free fermentates (CFSs) against several plant pathogenic fungi and oomycetes (fungisensu lato), includingAlternaria, Aspergillus Colletotrichum, Penicillium, PlenodomusandPhytophthora, was evaluatedin vitrousing the culture overlaying and the agar diffusion tests. Minimal inhibitory concentration (MIC) and minimal fungicidal concentration (MFC) were determined. LABs showed antifungal activity against the fungisensu latotested. The most noticeable inhibitory activity was shown by isolates ofL. plantarumandP. pentosaceusagainstFusarium oxysporum, Colletotrichumspecies andPenicillium nordicum. Chemical analysis revealed CFSs contained acid lactic and variable quantities of 14 diverse phenolic acids and 26 volatile organic compounds (VOCs). No obvious correlation was found between the metabolic profile of LABs and their antifungal efficacy. However, it is the first time that the potential of fermentates of LABs, recovered from drupes of olive oil varieties, as natural fungicides, was demonstrated.