A Study on the Screening for Lactic Acid Bacteria from Fura Da Nono with Antibacterial and Bio Preservative Properties

Abstract

The study explores the isolation and screening of lactic acid bacteria (LAB) from the traditional Nigerian fermented beverage fura da nono with a focus on their antibacterial and biopreservative properties. A total of fifty LAB strains were isolated using selective MRS agar, and presumptive identification was achieved via phenotypic characterisation. Four isolates displaying prominent antibacterial activity were further identified through 16S rRNA gene sequencing, revealing Lactobacillus plantarum FJ390111, Lactobacillus casei CP14326, and Enterococcus lactis NR117562, with an additional isolate, Lysinibacillus fusiformis, identified as an environmental contaminant. Crude bacteriocin extracts, obtained via ammonium sulfate precipitation and dialysis, were evaluated against foodborne pathogens, including Staphylococcus aureus, Salmonella typhi, and Escherichia coli using agar diffusion assays. The LAB bacteriocins demonstrated optimal inhibitory activity at pH 6 and 35 °C, whereas significant declines in activity were noted at temperatures above 40 °C and during extended storage (96 hours at 37 °C). Graphical data and tables confirm that the bacteriocin extracts produced zones of inhibition ranging from approximately 11 to 15 mm under optimal conditions, with Enterococcus lactis showing particularly moderate to high activity. These results underscore the potential application of LAB-derived bacteriocins as natural bio-preservatives in the food industry. However, the heat sensitivity and degradation over time highlight the need for further formulation improvements. The study concludes that with enhanced stabilisation and rigorous quality control, bacteriocins from traditional LAB can serve as effective alternatives to chemical preservatives in ensuring food safety and extending product shelf life.