Diversity of yeast strains isolated from the <i>“magnan’’</i> a traditional ferment used for the production of <i>“attiéké”</i> a cassava food in Côte d'Ivoire

Abstract

Objective: This study aimed to identify the yeasts in the traditional fermented cassava root called ''magnan'', used for fermentation of cassava dough for “attiéké: a fermented cassava food product’’ production in Côte d'Ivoire. Methodology and results: ‘magnan'' is a fermented cassava root used as a traditional starter and “attiéké’’ is a fermented cassava food product. This study involved 99 samples of ''magnan'' taken from different production areas in eleven (11) communes in the District of Abidjan (Abobo, Adjamé, Anyama, Attécoubé, Bingerville, Cocody, Koumassi, Marcory, Port-Bouët, Songon and Yopougon). Samples of ‘’magnan’’ were collected and carried to the Biotechnology Laboratory of the Félix Houphouët-Boigny University, during sixmonth (May - November 2017) and treated separately on MYPG medium (malt extract, yeast extract, peptone, glucose, and chloramphenicol). One hundred and six (106) pure yeast cultures were identified at genus and species level by MALDI-TOF mass spectrometry at the bio-bank laboratory of the Pasteur Institute of Côte d’Ivoire. A total of 83 yeast isolates were clearly identified (78.30 %) and showed five genus: Candida, Saccharomyces, Trichosporon, Kloeckera, and Millerozyma. The major species included C. krusei (30.12 %), C. tropicalis (28.92 %), and S. cerevisiae (20.50 %) followed by a low proportion of C. kefyr (6.02 %), C. guilliermondii (3.61 %), T. asahii (3.61 %), K. apis (2.41 %), C. pararugosa (1.20 %), M. farinosa (1.20 %) and C. albicans (1.20 %). Conclusion and application of the results: This study showed the traditional cassava ferment ''magnan'' used for the fermentation of cassava dough for the production of “attiéké ’’ on the sampled sites was colonized by several yeasts genera including Candida, Saccharomyces, Trichosporon, Kloeckera and Millerozyma in varying proportions. The frequently isolated species were composed by C. krusei, C. tropicalis and S. cerevisiae. The results obtained will constitute a database on the diversity of yeasts for the selection of starter strains for producing of “attiéké ’’. In perspective, the techno-functional properties (enzyme production: amylase, cellulase, pectinase, phytase, tannase and β-glucosidase) of each strain will be determined for their impact on the fermenting process of the cassava dough. And the starter strains will be used by producers to optimize and standardize the quality of “attiéké ’’.

Keywords: yeast strains, traditional ferment, “attiéké ’’, ‘’magnan’’