Antifungal activity of selected lactic acid bacteria from olive drupes

Abstract

In 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 (fungi sensu lato), includingAlternaria,Aspergillus,Colletotrichum,Penicillium,PlenodomusandPhytophthora, was evaluated in vitro using 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 fungi sensu lato tested. 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.

Brazilian Table Olives: A Source of Lactic Acid Bacteria with Antimycotoxigenic and Antifungal Activity

“…Panebianco and Caridi [ 41 ] also reported that 91% of the isolated LAB strains exhibited antagonistic activity against P. crustosum and 18% against Aspergillus sp., with the most representative strains being identified as L. pentosus and Fructilactobacillus sanfranciscensis . Simões et al [ 14 ] and Riolo et al [ 43 ] identified several LAB, isolated from olives, that showed strong inhibiting properties against P. nordicum . The potential of LAB as biopreservative agents in black olives was also studied in the work of El Oirdi et al [ 44 ], in which CFS from L. plantarum showed an important bioprotective effect against attack by A. fumigatus , delaying fungus growth for about 30 days, pointing to the possible use of indigenous isolates of lactic acid bacteria in the prevention of foods, such as fermented table olives.…”