Objective: To develop a PCR method for identifying the 16S rRNA of Lactobacillus and Streptococcus thermophilus at the species level.
Methods: Optimizing the method for DNA extraction and the conditions for PCR amplification. Joining the PCR amplification products from 16S rRNA to plasmid puc18-T and detecting the sequence.
Results: All 50 isolates recovered from yoghourt products were characterized by 16S rRNA sequence analysis and 7 groups were identified as L. bulgaricus (24 strains), S. thermophilus (12 strains), L. acidophilus (7 strains), L. casei (3 strains), L. delbrueckii (2 strains), L. fermentum (1 strain) and S. lutetiensis (1 strain).
Conclusion: 16S rRNA PCR method developed in this research is a sensitive and reliable method for the identification of both Lactobacillus and Streptococcus thermophilus.