Diversity and dynamics of lactic acid bacteria during Nonnonkoumou (artisanal curdled milk) production in Daloa, Côte d’Ivoire

Defined as an artisanal curdled milk, Nonnonkoumou is a commodity appreciated by the Ivorian population, particularly that of the city of Daloa. In this food, there are a diversity of lactic acid bacteria (LAB) which play a very important role in fermented products. The objective of this work was therefore to identify the LAB isolated during the Nonnonkoumou production in order to get to know them better and use them for biotechnological purposes. LAB were isolated from fermenting raw milk used for Nonnonkoumou production at different fermentation times (T₀, T_6H, T_12H, T_18H and T_24H). These LAB were characterized after Rep-PCR followed by partial sequencing of the 16S rRNA gene. The loads of LAB from Nonnonkoumou samples increase of 1.27 ± 0.12 log CFU / mL at 7.11 ± 0.43 log CFU / mL between 0 and 12 hours of fermentation. The maximum value (8.56 ± 0.18 log CFU / mL) is reached at 18 h of fermentation. The results of the Rep-PCR profile of 179 isolates revealed 8 distinct groups of LAB in Nonnonkoumou. After amplification and partial sequencing of the 16S rRNA gene of LAB strains, the 179 LAB isolates were classified into 8 species: Lactococcus lactis subsp cremoris (0.56%), Lactococcus Taiwanensis (16.20%), Weissella fabalis (12.29%), Wessiella confuse (3.35%), Lactiplantibacillus (10.06%), Weissella Hellenica (18.43%), Weissella paramesenteroides (1.68%) and Levilactobacillus brevis (37.43%). Thus, the study of this dynamics has made it possible to observe the natural variations in the composition of the LAB communities.