Probiotic potential of lactic acid bacteria isolated from a maize-based fermented beverage (kwete) consumed by ethnic communities in Northern Uganda

Lactic acid bacteria (LAB) from traditionally fermented beverages are widely recognized for their health-promoting effects and probiotic potential. This study compared LAB isolates from kwete in two sub-regions of Northern Uganda (Acholi: seven isolates; Lango: nine isolates) with the reference strain Lacticaseibacillus rhamnosus ATCC 7469. The isolates were evaluated for tolerance to gastrointestinal stress, functional properties, and antimicrobial activity. A one-way analysis of variance was conducted to compare the performance of isolates from the two sub-regions and the reference strain across probiotic parameters, with a significance level set at p < 0.05. Tukey’s HSD test was used for mean separation analysis. Results revealed distinct differences in probiotic performance between the isolates from the two sub-regions and the reference strain. Principal Component Analysis and Hierarchical Cluster Analysis were used to identify the most promising isolates. Notably, several isolates exhibited significantly higher values than Lb . rhamnosus ATCC 7469 for specific probiotic characteristics, including phenol (isolates 114,45,51); cell surface hydrophobicity (isolates 147, 104, & 99), survival under simulated gastric conditions (isolates 104 and 105) and survival under simulated pancreatin conditions (isolates 89 and 115) for 2 and 3 h. According to multivariate analyses (PCA and HCA), isolate 51 and 147 from Acholi sub-region and isolate 111 and 115 from the Lango sub-region showed the strongest overall associations with multiple probiotic attributes and were therefore identified as the most promising probiotic candidates. These results highlight that LAB from traditional fermented beverages in Northern Uganda are a valuable source of novel probiotic candidates for potential applications in health and nutritional interventions. The LAB isolates demonstrated several promising in vitro probiotic characteristics and one ex vivo characteristic; however, in vivo studies are required to validate their efficacy, safety, and functional performance before their application as probiotic candidates.