Pyrosequencing Analysis of the Microbial Diversity of Airag, Khoormog and Tarag, Traditional Fermented Dairy Products of Mongolia

Abstract

Here, we used pyrosequencing to obtain a detailed analysis of the microbial diversities of traditional fermented dairy products of Mongolia. From 22 Airag (fermented mare’s milk), 5 Khoormog (fermented camel’s milk) and 26 Tarag (fermented milk of cows, goats and yaks) samples collected in the Mongolian provinces of Arhangai, Bulgan, Dundgobi, Tov, Uburhangai and Umnugobi, we obtained a total of 81 operational taxonomic units, which were assigned to 15 families, 21 genera and 41 species in 3 phyla. The genus Lactobacillus is a core bacterial component of Mongolian fermented milks, and Lactobacillus helveticus, Lactobacillus kefiranofaciens and Lactobacillus delbrueckii were the predominant species of lactic acid bacteria (LAB) in the Airag, Khoormog and Tarag samples, respectively. By using this pyrosequencing approach, we successfully detected most LAB species that have been isolated as well as seven LAB species that have not been found in our previous culture-based study. A subsequent analysis of the principal components of the samples revealed that L. delbrueckii, L. helveticus, L. kefiranofaciens and Streptococcus thermophilus were the main factors influencing the microbial diversity of these Mongolian traditional fermented dairy products and that this diversity correlated with the animal species from which the milk was sourced.

Electrical Conductivity, pH, Minerals, and Sensory Evaluation of Airag (Fermented Mare’s Milk)

“…It is known that not only lactic acid bacteria but also many microorganisms, such as yeasts, are involved in airag [10][11][12][13][14][15], and both lactic acid bacteria and yeast have stimulatory and inhibitory effects on each other [16]. A change of EC was also observed in yeast cultures [17], and it was used to analyze the metabolic activity of lactic acid bacteria and yeasts during the lactic-acid-alcohol fermentation of goat's milk and mixtures of goat's milk and mare's milk [18].…”

Culture-independent bacterial community analysis of the salty-fermented fish paste products of Thailand and Laos

“…For example, product improvement could be achieved by monitoring the initial salinity, or possibly using the representative lactic acid bacteria as a fermentation starter so that the characteristic lactic acid bacteria communities develop steadily, leading to the creation of tastes and flavors that can meet the differing consumer preferences of various regions. Further microbial profiling of various pla-ra/pa-daek products in Thailand and Laos, using a combination of culture-independent analysis and a statistical approach, could reveal the regional characteristics and their link to product quality as in the cases of the production of traditional water-buffalo mozzarella cheese [ 21 ], and the fermented dairy products of Mongolia [ 22 ].…”

Review: Diversity of Microorganisms in Global Fermented Foods and Beverages

“…“Functionally relevant phylotypes” in an ecosystem may be specifically detected by, e.g., weighted UniFrac principal coordinate analysis based on 454 pyrosequencing of 16S rRNA genes, as applied in studies on gut microbiota (Wang et al, 2015 ). The 16S rRNA gene sequence based pyrosequencing method enables a comprehensive and high-throughput analysis of microbial ecology (Sakamoto et al, 2011 ), and this method has been applied to various traditionally fermented foods (Oki et al, 2014 ).…”