Probiotic Activities of Lactic Acid Bacteria Isolated from Different Types of Pap Against Selected Bacterial Strains

Abstract

Probiotics are different kinds of living organisms that have beneficial health effects on humans. Their first origin was from dairy products, but today most probiotic organisms are sources from fermenting fruits and other agricultural products. Lactic acid bacteria (LAB) majorly used as probiotics are groups of Gram-positive, non-sporulating, anaerobic or facultative aerobic cocci or rods, which produce lactic acid as one of the main fermentation products of metabolism from carbohydrates sources. This study investigated the probiotic potential of lactic acid bacteria (LAB) isolated from different types of ogi (pap), a traditional fermented cereal porridge made from maize (Zea mays), millet (Pennisetum typhoideum), and guinea corn (Sorghum bicolor). A total of fifteen ogi samples were collected from Eke Awka market, Nigeria. Using pour-plate method, total bacterial count was done using nutrient agar while total LAB count was done using deMan Rogosa and Sharpe (MRS) agar. Isolates that developed on the plates were characterized and identified using standard biochemical methods. Molecular identification of the isolates were also done using 16s rRNA sequencing. The isolates were evaluated for probiotic properties, including tolerance to NaCl (2–8%), bile salts (0.3%), and phenol (0.1–0.4%). The antimicrobial activity of crude bacteriocins from the LAB isolates was tested against multidrug-resistant clinical specimen namely; Staphylococcus aureus, Enterococcus faecalis, Bacillus cereus, Escherichia coli, Salmonella enterica, and Pseudomonas aeruginosa. Results indicated that the total bacterial counts ranged from 3.50 × 104 to 2.30 × 105 CFU/ml, while LAB counts ranged from 1.80 × 104 to 8.90 × 104 CFU/ml in seven of the samples. Five LAB isolates were phenotypically identified as Pediococcus acidilactici, Lactobacillus delbrueckii, Lactobacillus plantarum, Lactobacillus fermentum, and Leuconostoc mesenteroides. Molecular identification via 16S rRNA sequencing confirmed the isolates to be Lactiplantibacillus plantarum and Lacticaseibacillus rhamnosus. All LAB isolates exhibited inhibitory effects against at least three pathogens, with Lactiplantibacillus plantarum (J3) showing broad-spectrum activity against all test organisms. The findings showed that traditionally fermented ogi is a valuable source of probiotic LAB which can be harnessed and purified and used against some multidrug resistant organisms to achieve healthy conditions.