The results of species-specific PCR and16S rRNA gene sequencing
were consistent with those of the reference S. thermophilus strain.
PFGE analysis helped to differentiate 61 isolated strains into 22
homology groups (Table 2). Carbohydrate utilization tests provided
useful information on the phenotypic diversity and revealed 22
different profiles. Most of the profiles were atypical for
S. thermophilus strains, and only 7 of the strains were found to be
very similar to S. thermophilus type-strain. Comparison of PFGE
homology groups with carbohydrate utilization profiles didn’t give
any overlap and revealed the presence of further phenotypic heterogeneity
within PFGE homology groups. Furthermore isolates
were further tested for their technological performance to be used
as yoghurt starter culture. Majority of the isolates were determined
to be protease positive and had fast acidification in milk.