Antifungal Properties of Lactic Acid Bacteria Isolated from Pentaclethra macrophylla, Ricinus communis and Zea mays
C. V. Uzoh *
Department of Microbiology, Alex-Ekwueme Federal University Ndufu- Alike Ikwo, Abakaliki, Ebonyi State, Nigeria.
P. C. Igwe
Department of Microbiology, David Umahi Federal University of Health Sciences, Uburu, Ebonyi State, Nigeria.
C. O. Uzoh-Chukwuma
Department of Science Laboratory Technology, Akanu Ibiam Federal Polytechnic, Unwana, Ebonyi State, Nigeria.
A. A. Adeshina
Department of Microbiology, Alex-Ekwueme Federal University Ndufu- Alike Ikwo, Abakaliki, Ebonyi State, Nigeria.
L. I. Uwanta
Department of Applied Microbiology and Brewing, Nnamdi Azikiwe University Awka, Anambra State, Nigeria.
*Author to whom correspondence should be addressed.
Abstract
Locally fermented foods can harbour lactic acid bacteria (LAB) with antimicrobial activity that may be useful in food biopreservation. This study investigated the antifungal activity of LAB isolated from Pentaclethra macrophylla, Ricinus communis and Zea mays against selected fungal contaminants. LAB isolates were cultured and characterised using standard microbiological procedures, while fungal isolates were obtained from contaminated plant materials and identified by their macroscopic and cultural characteristics. Antifungal activity was assessed under in vitro agar conditions, and inhibition zones were recorded. The susceptibility pattern differed among the fungal isolates and LAB tested. Aspergillus fumigatus was inhibited by several LAB isolates, with inhibition-zone diameters ranging from 10 to 17 mm among the responding isolates; recorded values included 10 mm for Lactococcus lactis, 15 mm for Streptococcus sp., and 17 mm for Lactobacillus sp. Lactobacillus sp. also inhibited Aspergillus flavus, while Lactococcus lactis inhibited Rhizopus sp. Aspergillus niger was inhibited by Lactococcus lactis and Lactobacillus salivarius. Pediococcus sp. produced no measurable inhibition against the tested fungi under the assay conditions. Overall, the findings demonstrate differential in vitro antifungal activity among the LAB–fungus combinations. Selected isolates may therefore have potential as natural food-grade biopreservative candidates, although their effectiveness requires confirmation in relevant food matrices under appropriate processing and storage conditions before practical application.
Keywords: Lactic acid bacteria, antifungal activity, biopreservation, fermented foods, Pentaclethra macrophylla, Ricinus communis, Zea mays, fungal spoilage