Isolation and Characterisation of Lactic Acid Bacteria Isolated from Artisanal Cheese (Tchoukou) from the Niger Republic

Lactic Acid Bacteria (LAB) are industrially essential microorganisms widely used as starter cultures in the production of dairy, meat, cereal, vegetable, and alcoholic beverages. Beyond their technological role, LAB contribute to human health by enhancing gastrointestinal function, producing antioxidant metabolites, inhibiting pathogenic bacteria, and supporting immune activity. Isolation and characterisation are essential steps in evaluating their functional properties. In this study, LAB were isolated from artisanal cow milk cheese, known locally as Tchoukou, using selective media. Identification relied on phenotypic, biochemical, and genotypic traits. 16S rDNA analysis of isolates from Maradi, Tahoua, and Zinder regions of Niger revealed clustering with Lactobacillus plantarum (76.48%) and Lactococcus garvieae. Phenotypic and biochemical tests confirmed Lactobacillus as rod-shaped, Gram-positive, and Lactococcus as coccoid, Gram-positive. All isolates were catalase-negative and sugar-fermenting, supporting their taxonomic classification. Functional assays showed tolerance to acidic conditions (pH 3.0-3.5) and optimal growth at 37-40 °C. Antibiotic susceptibility testing indicated sensitivity to gentamicin, sulphamethoxazole, chloramphenicol, ampicillin, tetracycline, and co-trimoxazole. Findings highlight the dominance of Lactobacillus in Tchoukou cheese and suggest probiotic potential due to acid tolerance. However, antibiotic sensitivity patterns warrant further functional evaluation for industrial applications.