The specific objectives of this research were (i) to develop broad-scale bioinformatics data from three lactic acid bacteria (LAB) strains - S. thermophilus KLDS 3.1003, SMQ-301, and LMD-9 genomes, (ii) to mine the relevant genes that confer probiotic and industrial properties to the strains, and (iii) show a more precise correlation between reported in vitro and in vivo properties of these strains and their genome characteristics. These LAB strains have an array of genes for antioxidant properties, which endows them with the capacity to mitigate incidences of oxidative stress. However, the gene for peroxidase coding is conspicuously absent in S. thermophilus KLDS 3.1003 but present in LMD-9 and SMQ-301, respectively (STER_RS05050, SMQ301_RS05030). All three strains have an F0F1-ATPase system, consisting of genes assigned for the F0F1-ATPase synthase cluster (4 assigned genes each) and urease cluster (15 assigned genes each). Furthermore, S. thermophilus LMD-9 is the only confirmed PrtS+ strain (STER_RS04165). Interestingly, it was shown for the first time that the S. thermophilus KLDS 3.1003 genome harbors the PepX hydrolase (BEN15_RS01405), also believed to have similar functions with the PrtS enzyme. These findings demonstrate that NGS is a powerful tool in demonstrating the industrial and therapeutic potentials of the studied S. thermophilus strains. It also gives further insights into the properties of these strains that have not been previously reported, such as the bacteriocin configuration in SMQ-301 and KLDS 3.1003.

Keywords: S. thermophilus, bioinformatics, foodborne diseases, oxidative stress, bacteriocin