Molecular identification and species diversity of the microbiota associated with Soumbara, a traditional fermented food commonly consumed in Cote d’Ivoire

The aim of this study was to investigate the species diversity of microbiota isolated from soumbara, a traditional alkaline-fermented food and the microbial distribution in six major producing regions in Côte d'Ivoire. Ribosomal gene sequencing revealed that the Ivorian soumbara is associated with a wide microbial diversity essentially composed of 10 Bacillus species representing more than 90% of total microbial isolates, 3 species of lactic acid bacteria (2.48%), 2 species of Staphylococcus (1.42%), 8 fungal species (4.61%) and 1.06% of other microorganisms. However, the PCR-RFLP revealed a very weak intraspecific diversity as strains belonging to the same species showed a single restriction profile. Moreover, the microbiota associated with Ivorian soumbara consisted in a core and autochthonous microbiota namely B. subtilis and B. velezensis that were consistently present in samples from all regions studied and an incidental microbiota that was variable through the regions. Among the variable microorganisms, the presence of potential pathogen opportunistic such as Staphylococcus pasteuri, Staphylococcus sciuri and toxinogen species such as B. cytotoxicus and Aspergellus flavus were particularly found. The core microbiota is believed to be involved in the normal process of African locust beans into soumbara and can serve as potential starter whereas the incidental and variable microbiota rather undesirable may be involved in the spoilage or food-born disease. In this study, many species were described for the first time in soumbara, and revealed a new biodiversity of microbiota associated with soumbara in Côte d’Ivoire.