Isolation and biochemical and molecular identification of Lactobacillus bacteria with probiotic potential from traditional cow milk and yogurt of Khoi city

Narimani, Tahereh; Tari Nejad, Ali Reza; Hejazi, Mohammad Amin

Isolation and biochemical and molecular identification of Lactobacillus bacteria with probiotic potential from traditional cow milk and yogurt of Khoi city

Authors

Tahereh Narimani

Ali Reza Tari Nejad

Mohammad Amin Hejazi

Abstract

Probiotics are live microorganisms which when consumed in adequate amounts, can have a beneficial effect on the host. Lactic acid bacteria are the most common type that have been introduced as probiotics and are present in dairy products. The aim of this study was to isolate and identify the probiotics from microbial flora of cow milk and its traditional yogurt in Khoi area. To achieve this goal, the lactic acid bacteria were isolated by phenotypic methods (cellular morphology, colony pigmentation, Gram staining, catalase test, biochemical tests including growth in different temperatures 10°C, 15 °C and 45 °C, various concentrations 4 % and 6.5 % of salts and fermentation of 17 types of sugar) and their probiotic potential (resistant to stomach acid and bile salts) were evaluated. Then, to identify more accurately, the 16S rRNA gene of Lactobacilli were replicated with pairs of specific primers and then the purified PCR product was sent for gene sequencing. At the end, 14 strains of Lactobacilli were reported as the natural microbial flora with probiotic potential in Khoi area. These bacteria provide the good quality of the dairy products in those areas and can be used as the starter culture in industrial manufacture of dairy products.

Keywords

Probiotic

Lactobacillus

16S rRNA gene