Characterisation of Lactiplantibacillus plantarum Isolated from Soumbara (Korhogo, Côte d’Ivoire)

Abstract

Soumbara, a traditional condiment obtained from fermented Parkia biglobosa seeds, contributes to the dietary practices of populations in northern Côte d’Ivoire. This study characterised lactic acid bacterial isolates recovered at the early stage of Soumbara fermentation in Tioroniaradougou, Korhogo Department. Samples were collected from three traditional producers, and lactic acid bacteria were isolated and enumerated on MRS agar according to the AFNOR standard. Presumptive isolates were examined using morphological, phenotypic, biochemical and molecular approaches. Lactic acid bacterial counts were higher at the start of fermentation in samples from P1 and P2 (5.67 ± 0.7 and 5.65 ± 0.7 Log₁₀ CFU/g, respectively) than in P3 (3.03 ± 0.5 Log₁₀ CFU/g), and declined markedly by the end of fermentation to 1.05 ± 0.5, 0.63 ± 0.6 and 0.46 ± 0.4 Log₁₀ CFU/g, respectively. Three representative isolates, designated S1, S2 and S3, were Gram-positive, catalase-negative, oxidase-negative rods with homofermentative metabolism and no gas production from glucose. The isolates fermented L-arabinose, lactose, mannitol, melibiose and raffinose, but not D-xylose, and grew at 15 °C and 45 °C. Molecular identification based on partial 16S rRNA gene sequencing assigned all isolates to Lactiplantibacillus plantarum, with sequence homology values ranging from 98.73% to 99.82%. These findings provide preliminary evidence for the involvement of indigenous L. plantarum strains during the early phase of Soumbara fermentation and support further functional and safety evaluation.