Comparative Genome Analysis and Assessment of the Functional Properties of Streptococcus thermophilus Strains.

Many different strains of Streptococcus thermophilus are commonly used as starter cultures, and search for new safe strains with desired industrial and probiotic properties is an important issue. In this article, genomes of two new S. thermophilus strains—Str16t and Str159—were sequenced, and the main genome characteristics were determined. In silico analysis of the sequenced 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 bacteriocins were found. In vitro tests showed phosphatase, peptidase, β-galactosidase, and esterase activity of both strains. Both strains were capable of fermenting glucose, lactose, sucrose, and ribose; in addition, Str16t fermented mannose. In conclusion, it was demonstrated that both Str16t and Str159 are promising strains for application as starter and probiotic cultures. [ABSTRACT FROM AUTHOR]