Isolation and identification of lactic acid bacteria with probiotic potential from fermented flour of selected banana varieties grown in Sri Lanka

This study aimed at isolating and identifying lactic acid bacteria (LAB) with probiotic potential from fermented flour of selected banana varieties grown in Sri Lanka and evaluating their probiotic and safety attributes in vitro. Ten lactic acid bacteria were isolated from six varieties of fermented banana flour, kolikuttu, seeni parakum, ambul nadee, ambum, seeni and anamalu. The isolates were screened for phenotypical and biochemical characteristics. The selected isolates were identified by 16 S rRNA sequencing as Enterococcus durans (two strains), E. gallinarum, E. hirae, E. faecium (two strains), Lactobacillus plantarum, L. curieae, Weissella cibaria and Pediococcus acidilactici and their partial sequences were deposited in NCBI. Among them, six isolates were selected based on the results of in vitro safety attributes and evaluated for their probiotic attributes. Three isolates, namely, E. durans MF405179.1, E. faecium MF574466.1 and L. curieae MF405178.1 isolated from kolikuttu, seeni parakum and ambul nadee, respectively demonstrated tolerance to acid, gastric juice, bile, salt, phenol and temperature under gastric conditions, and also showed susceptibility to tested antibiotics. Among the selected isolates, E. durans MF405179.1 demonstrated the highest hydrophobicity and auto-aggregation of 69.91 % and 76.53 %, respectively. Further, it exhibited highest adhesion to both HCT116 and HT29 cell lines demonstrating 72.5 % and 74.16 % adhesion, respectively. This is the first report of isolation and characterisation of LAB strains with probiotic potential from flour of banana varieties kolikuttu, seeni parakum, ambul nadee, ambum, seeni and anamalu grown in Sri Lanka.