DNA EXTRACTION OF LACTOBACILLUS BULGARICUS AND STREPTOCOCCUS THERMOPHILUS OBTAINED FROM SELECTED YOGHURTS, YOGOURMET AND SOY WARA BOUGHT FROM VARIOUS MARKETS IN SOUTH WESTERN NIGERIA

Abstract

– Streptococcus thermophilus and Lactobacillus bulgaricus are important members of Lactic acid bacteria, because of their enormous technological and commercial importance in the production of various dairy products, and because they are generally recognized as safe (GRAS) microorganisms. The aim of the study was to optimize the molecular detection and quantification of DNA of various Streptococcus thermophilus and Lactobacillus bulgaricus obtained from selected Yoghurts, Yogourmet as well as Soy wara using Zymo genomic kits. The result confirmed that Zymo genomic kits are superior to use of other methods. Streptococcus thermophilus and Lactobacillus bulgaricus strain B 37 , B 35 , B 36 and B 38 had a DNA purity ranging from 1.78 and 2.1 , while Lactobacillus bulgaricu s strain B 39 , B 40 and B 41 had a DNA Purity ranging from 1.93 and 1.97. The result justifies that higher purity and yield is characteristic of the method. The Agarose Gel Electrophoresis confirmed the DNA of Streptococcus thermophilus and Lactobacillus bulgaricus at 1500 bp are obtained from Commercial yoghurts and Yogourmet, while the starter cultures obtained from Soy wara did not show any amplification bands.