Browsing by Author "Acuna-Fontecilla, Andrea"

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    Antimicrobial Activity of Leaf Aqueous Extract of Schinus polygamus (Cav.) Cabrera against Pathogenic Bacteria and Spoilage Yeasts
    (2024) Acuna-Fontecilla, Andrea; Bruna, Julio; Ganga, Maria Angelica; Godoy, Liliana
    The antimicrobial activity of an aqueous extract of the leaves of Schinus polygamus (cav.) Cabrera against microorganisms of food importance was evaluated. First, the leaf aqueous extract of Schinus polygamus was characterized, quantifying hydroxycinnamic acids and phenolic compounds. Then, a battery of strains was tested, including Escherichia coli ATCC 25922, Salmonella Typhimurium ATCC 14028, and Listeria monocytogenes ATCC 13932. Also, we tested wine spoilage yeasts such as Brettanomyces bruxellensis LAMAP2480, B. bruxellensis LAMAP1359, B. bruxellensis CECT1451, and Pichia guilliermondii NPCC1051. Tests were conducted using the kinetic curve of growth and cell viability counts. The results indicate that with 10% v/v of concentrated extract, it is possible to observe growth inhibition of all microorganisms studied, with statistically significant differences during the whole measurement time (70 h for bacteria and 145 h for yeast).
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    Non-conventional yeasts as biocontrol agents against fungal pathogens related to postharvest diseases
    (2022) Reyes-Bravo, Paula; Acuna-Fontecilla, Andrea; Marlene Rosales, Ines; Godoy, Liliana
    There are numerous investigations related to biological control and the use of microorganisms as new control strategies. In this sense, yeasts have been reported to have biocontrol activity and could be interesting candidates for BCA development. The main goal of this study was to evaluate the antagonist effect of four endophytic yeast, Naganishia antarctica YCPUC12, Aureobasidium pullulans YCPUC14, Cryptococcus terrestris YCPUC16 and Filobasidium oeirense YCPUC41 over the growth of Botrytis cinerea MPC40, Monilinia laxa MPC71, Penicillium expansum MPC102 and Geotrichum candidum MPC115.Three experimental approaches were used to evaluate biocontrol effect of yeast. Two in vitro assays (agar plug diffusion and dual-culture) and one in vivo assay. The results obtained here revealed that the four yeast strains evaluated showed inhibitory effect against the phytopathogens tested. Furthermore, it is indicated that the inhibitory effect by the yeasts over the fungi is differential, suggesting that there could be involved more than one antagonist-mechanism on the part of yeasts. Yeasts produce compounds capable of inhibiting the growth of fungi and, depending on the assay, the evaluated antagonist-yeasts have differential biocontrol effect against these pathogens. Their potential as biocontrol agents for postharvest diseases are interesting, and further investigation is needed to verify the effectiveness of these antagonists.