was represented by only one genus, Lactobacillus, which accounted
for 99.7, 93.9, and 99.6% of the reads for grains AR, AV and AD
respectively (Fig. 4). In the family Streptococcaceae, the genus
Streptococcus comprised only 0.01% and 0.04% of all sequences
identified in grains AV and AD respectively, whereas the genus
Lactococcus was detected only in kefir grain AV (4.87% of the reads).
The genus Leuconostoc also occurred at a low level in samples AV
(0.12%) and AD (0.23%). Few sequences were assigned to the
phylum Proteobacteria, which accounted for 0.3% of the total
assigned sequences for grain AR, 1% for AV and 0.04% for AD. The
sequences of this phylum belonged to the genus Acetobacter in
sample AR (0.26%) and AD (0.04%), and to the genus Pseudomonas
(0.99%) in sample AV. Phylum Actinobacteria was represented by
reads belonging to the genus Solirubrobacter in grain AR (0.04%)
and the genus Bifidobacterium in grain AV (0.02%).
Because of the low diversity found, unique representative
sequences from each OTU were selected and used to construct
a phylogenetic tree (Fig. 5). The different sequences were manually
compared against the RDP database and further aligned with up to
three of their nearest sequences in the database. The majority of the
OTUs represented close phylogenetic lineages of Lactobacillus spp.