Comparative Genome Analysis and Assessment of the Functional Properties of <i>Streptococcus thermophilus</i> Strains

Streptococcus thermophilus are commonly used as starter cultures. Search for new safe strains with desired industrial and probiotic properties is an important issue. Complete genome sequencing was carried out, and the main genome characteristics of two new strains, S. thermophilus 16t (Str16t) and 159 (Str159), were determined. In silico analysis of the genomes revealed the absence of transmissible antibiotic resistance genes, virulence genes associated with pathogenicity, and integrated plasmids; gene clusters encoding class I and class II bacteriocin were found. In vitro tests showed phosphatase, peptidase, β-galactosidase, and esterase activity of both strains, as well as their ability to ferment glucose, lactose, sucrose, and ribose. Strain Str16t metabolized mannose as well. Str16t and Str159 are promising strains for application as starter and probiotic cultures.