بررسی تنوع باکتری های اسید لاکتیک جدا شده از کشک زرد زابلی (سیستانی) با استفاده از روش تکثیر ژن 16S rRNA

Fermentation is used for centuries to protect quality improvements or flavor modifications of cereals, fruits, vegetables, milk and meat. Yellow Zabol kashk (Sistani) is a grain-dairy fermented product, which is highly consumed in Sistan-Baluchistan province. The aim of this study was to isolate and identify the Lactic Acid Bacteria involved in spontaneous fermentation of this product to introduce the native strains. These strains could be used in industry or some of them may be considered as probiotic strains. The cell morphology of each strain was investigated. Then gram-positive and catalase-negative isolates were selected. In order to classify 83 selected isolates that seemed Lactic Acid Bacteria according to preliminary experiments, physiological and biochemical tests, including growth at 10°C and 45°C, 6.5% NaCl, pH=4.4 and pH=9.6, carbon dioxide production from Glucose and carbohydrates fermentation were performed. Twenty eight selected isolate identified genotypically based on 16S rRNA gene sequencing. The results showed that the isolates belong to: Lactobacillus plantarum (24.09 %), Lactobacillus helveticus (13.25 %), Lactobacillus brevis (963 %), Lactobacillus delbrueckii (18.07 %), Lactococcus lactis (13.25 %), Leuconostoc mesenteroides (9.63 %), Leuconostoc citreum (2.40 %) and Pediococcus pentosaceus (9.63 %). To identify the bacteria, especially lactic acid bacteria it is suggested using both culture and molecular-based method.