Bacterial community dynamics of back-slopped laboratory
rye sourdough samples analyzed through culture-dependent
and culture-independent approaches
Identification of 203 isolates (Table 3) as well as 16S rRNAPCR-
DGGE analysis of DNA extracted from rye sourdough samples
(Fig. 2) revealed the evolution of slightly different LAB communities
during all rye sourdough fermentations, although a similar species
composition was seen in the stabilized (240 h) rye sourdough
samples (Fig. 2). Indeed, the major changes occurred from day 0 to
day 4. During the first two days, mainly species belonging to the
genera Lactococcus, Leuconostoc, and Weissella were found, such as
Lactococcus lactis, Leuconostoc citreum, and Weissella confusa,
respectively. Lactobacillus curvatus and Pediococcus pentosaceus
were found after the second day of fermentation, dominating the
sourdough ecosystem on day 3. L. fermentum and L. plantarum were
found from day 3 on. Indeed, in three out of four stabilized rye
sourdoughs, a same composition of the LAB community, consisting
of L. plantarum and L. fermentum, was seen. Alternatively, culturedependent
analysis of the stable rye B sourdough revealed the
presence of P. pentosaceus and L. brevis in addition to L. plantarum
and L. fermentum. Further, a common band was found in all DGGE
patterns, which after extraction and sequencing appeared to
correspond with mitochondrial cereal DNA (Fig. 2).