Bacteriocin can be used as a natural non-toxic antibacterial agent in foods because of its resistance to foodborne pathogens and spoilage bacteria. Bioinformatics is a subject based on computer science and applied mathematics, which aims to locate the functional genes by searching for and comparing the biological information measured in the field of life science and analyzing the related nucleic acid information and structural protein genes. Transcriptomics aims to analyze all RNA transcribed by different cells or tissues under specific conditions at the overall transcriptional level, providing insights into biological pathways and molecular regulatory mechanisms. By comparing mass transcriptome sequencing data with the reference genome, the genetic information of transcripts can be quantitatively analyzed at the level of gene expression. Gene ontology (GO) annotation and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway enrichment analysis can be used to speculate the functional characteristics of differentially expressed genes selected by differential expression folds and further understand the mechanism of the synthesis of bacteriocin and other metabolites. Transcriptome sequencing is a safe and economical technology that is expected to provide a new approach for the large-scale production of bacteriocins.

Lactobacillus delbrueckii subsp. bulgaricus and Streptococcus thermophilus strains were isolated from commercial yogurts using selective media, and physiological and biochemical tests, sugar fermentation experiments and 16S rDNA homology analysis were used to identify the isolated strains. Genotyping of the strains was performed by pulsed field gel electrophoresis (PFGE). It was found that both Lactobacillus delbrueckii subsp. bulgaricus and Streptococcus thermophilus were detected in all yogurt samples. Streptococcus thermophilus had the same genotyping only in two yogurts, while other Lactobacillus delbrueckii subsp. bulgaricus and Streptococcus thermophilus strains were different in different yoghurts. The results showed that PFGE was an effective method for genotyping of different strains of Lactobacillus delbrueckii subsp. bulgaricus and Streptococcus thermophilus.