Assessment and Characterization of Lactic Acid Bacteria Isolated from Fermented African oil Bean Seed (Pentaclethra macrophylla) for Probiotic Application

Abstract

Among the bacteria in fermented foods, lactic acid bacteria play a pivotal role and its main function is to convert carbohydrates and other related raw materials into lactic acid (organic acid). Therefore, the aim of this research was to assess and use lactic acid bacteria isolates obtained from fermented African oil bean seeds as probiotics. Lactic acid bacteria were isolated using MRS agar and screened for organic acid production and the ability to tolerate some environmental conditions such as temperature, pH, and osmotic pressure. The use of the isolates as probiotics was investigated by screening and determining the antimicrobial inhibitory zone diameter of the isolates obtained against the indicator microorganisms such as Staphylococcus aureus, Bacillus cereus, Escherichia coli and Listeria monocytogenes. Results show that isolate2, isolate3, isolate5, isolate6, isolate7 and isolate8 were able to produce organic acid. Out of the six bacterial isolates tested for antimicrobial activities against the indicator microorganisms, isolate2, isolate3, isolate6 and isolate8 were able to show antimicrobial activities against Staphylococcus aureus, Bacillus cereus, Escherichia coli and Listeria monocytogenes using different dilutions (10- 1 to 10- 3) of the isolates. The isolates were able to grow at temperatures of 37oCand 45oC; pH of 2.5, 3.0, 3.5 and 4.0; finally the osmotic pressure of 1.0, 1.5, 2.5 and 5.0 % w/v NaCl. The isolates were identified as Lactobacillus species and can be used as probiotics.