K. Kuti1, I.M. Hussaini1*, A. Usman2, A. Isa1
1Department of Microbiology, Faculty of Life Sciences, Ahmadu Bello University, Zaria, Nigeria
2Department of Microbiology, Faculty of Science, Kaduna State University, Kaduna, Nigeria
(Manuscript received 24 December 2020; accepted for publication 10 May 2021)
Abstract. Food fermentation has been a tradition for decades due to its immense benefits. Lactic acid bacteria are known to possess probiotic potential due to various chemical antimicrobial substances they produce. This research was aimed at isolating Lactobacillus spp. from locally fermented locust beans and screening the isolates for their probiotic potential. A total of 20 samples of fermented locust beans (P. biglobosa) were collected and processed. The samples were inoculated onto de-Mann Rogosa Sharpe (MRS) media and incubated anaerobically. The isolates with characteristic colonial morphology of Lactobacillus sp. were characterized using Gram staining and biochemical tests. Lactobacillus spp. isolates were screened in-vitro for probiotic potential using the following parameters, tolerance of low pH, bile tolerance and antimicrobial activity. Four isolates of Lactobacillus species consisting of Lactobacillus fermentum and Lactobacillus plantarum were isolated from different fermented locust beans. All isolates showed tolerance to low pH and bile concentration of 3.04 and 0.3%, respectively. The Lactobacillus species isolates showed varying antibacterial activity against all test bacteria with isolate S06 (L. plantarum) showing the highest degree of antibacterial activity. In conclusion, the Lactobacillus species isolated from fermented locust beans can serve as probiotic candidate.