Streptococcus thermophilus is a traditional starter. Nowadays, key aspects of S. thermophilus physiology have been revealed concerning the phenotypic traits relevant for industrial applications, including sugar metabolism, protein hydrolysis, and the production of important metabolites that affect the sensory properties of fermented foods as well as the original cooperation with Lactobacillus delbrueckii subsp. bulgaricus. Moreover, significant advances have been made in the synthetic biology toolbox of S. thermophilus based on technological advances in the genome and its sequencing and synthesis. In this review, we discuss the recently developed toolbox for S. thermophilus, including gene expression toolsets (promoters, terminators, plasmids, etc.) and genome editing tools. It can be used for both functionalized foods and therapeutic molecules for consumers. The availability of new molecular tools, including the genome editing toolbox, has facilitated the engineering of physiological studies of S. thermophilus and the generation of strains with improved technical and functional characteristics.
