Analysis of 16S rRNA Gene of Lactic Acid Bacteria Isolated from Curd and Raw Milk

Raw milk and curd samples from various dairy outlets in the city were collected and putative lactic acid bacteria were isolated on MRS agar. These were first screened using preliminary criteria and then identified by analysing the 16S rRNA gene. For the molecular identification, extraction and quantification of bacterial DNA was first performed and the isolated DNA was amplified by PCR. This PCR product was then purified and sequenced using specific primers. The DNA sequences were then analysed using BLASTn and the results were used to generate a phylogenetic tree. From a total of four samples of curd and six samples of raw milk, the organisms identified were Lactobacillus fermentum in all the four samples of curd and one sample of raw milk. The rest of the five samples of raw milk showed two of the isolates to be Weisella confusa (basonym Lactobacillus confusus) and three to be Weisella cibaria.