Metagenomic analysis of the microbial community in kefir grains

Nalbantoğlu, Ufuk; Cakar, Atilla; Dogan, Haluk; Abacı, Neslihan; Ustek, Duran; Sayood, Khalid; Can, Handan

doi:10.1016/j.fm.2014.01.014

Cited by 137 publications

(120 citation statements)

References 39 publications

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“…tolerans. Nalbantoglu et al (2014) reported on a metagenomic analysis of the microbial community in kefir grains, finding Lb. kefiranofaciens to be the predominant species.…”

Section: Microbiological Characteristicsmentioning

confidence: 99%

A review: chemical, microbiological and nutritional characteristics of kefir

Arslan

2014

CyTA - Journal of Food

117

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Kefir, a mildly acidic fermented milk, is produced by the addition of lactic acid bacteria and yeasts to milk. The composition of kefir varies according to factors such as milk type and the microbiological composition of culture types (kefir grain and commercial starter culture). Kefir's distinctive flavour is a blend of lactic acid, ethanol, carbon dioxide and flavouring products, such as acetaldehyde and acetoin. The microorganisms in kefir produce vitamins, degrade protein and hydrolyse lactose, resulting in a highly nutritious and digestible foodstuff. The microbiological composition of kefir has been investigated using a wide range of microbiological and molecular approaches. The microbiological and chemical composition of kefir indicates that it is a very complex probiotic, with Lactobacillus species, generally the predominant microorganisms. Kefir is now increasingly being consumed in certain areas of the world, such as southwestern Asia, Europe, North America and Japan.Keywords: kefir; composition; nutrition; fermented milk product; microbiological properties El kéfir, una leche fermentada ligeramente agria se produce añadiendo bacterias ácido-lácticas (BAL) y levadura a la leche. La composición del kéfir cambia según los diferentes factores como: el tipo de leche, la composición microbiológica de los gránulos de kéfir y su cultivo. El kéfir posee un sabor distintivo gracias a la combinación de ácidos lácticos, etanol, dióxido de carbono y otros aditivos, como el acetaldehído y la acetoína. Los microorganismos en el kéfir producen vitaminas, crean degradación proteínica y provocan hidrólisis de lactosa. Por ese motivo, el kéfir se ha convertido en un alimento muy nutritivo y digestivo. La composición microbiológica del kéfir ha sido investigada utilizando varios enfoques microbiológicos y moleculares. La composición microbiológica y química del kéfir indica que se trata de un alimento probiótico muy complejo. Los Lactobacillus generalmente son conocidos como microorganismos dominantes en el kéfir. El consumo de kéfir está creciendo en algunas partes del mundo como en Asia, Europa, Norteamérica y Japón.

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“…tolerans. Nalbantoglu et al (2014) reported on a metagenomic analysis of the microbial community in kefir grains, finding Lb. kefiranofaciens to be the predominant species.…”

Section: Microbiological Characteristicsmentioning

confidence: 99%

A review: chemical, microbiological and nutritional characteristics of kefir

Arslan

2014

CyTA - Journal of Food

117

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“…Its fermentation pattern is homofermentative: it produces d-lactic acid, has a G+C content of 35 mol%, and does not grow at temperatures below 15°C. By comparing whole genome sequencing and 16S pyrosequencing on 2 Turkish kefir grains, Nalbantoglu et al (2014) also established that this bacterium constitutes the majority of the kefir microbiota. In kefir E, we isolated mainly Lc.…”

mentioning

confidence: 93%

“…lactis. Other authors have rarely isolated this bacterium in kefir grains or kefir; however, by using PCR-denaturing gradient gel electrophoresis (DGGE), Chen et al (2008) recovered it in 2 grains out of the 3 samples they analyzed, whereas Nalbantoglu et al (2014) showed that its relative abundance was below 0.01%. This contradicts Kesmen and Kacmaz (2011), who found that Lc.…”

mentioning

confidence: 99%

Short communication: Evaluation of the microbiota of kefir samples using metagenetic analysis targeting the 16S and 26S ribosomal DNA fragments

Korsak

Taminiau

Leclercq

et al. 2015

Journal of Dairy Science

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Milk kefir is produced by fermenting milk in the presence of kefir grains. This beverage has several benefits for human health. The aim of this experiment was to analyze 5 kefir grains (and their products) using a targeted metagenetic approach. Of the 5 kefir grains analyzed, 1 was purchased in a supermarket, 2 were provided by the Ministry of Agriculture (Namur, Belgium), and 2 were provided by individuals. The metagenetic approach targeted the V1-V3 fragment of the 16S ribosomal (r)DNA for the grains and the resulting beverages at 2 levels of grain incorporation (5 and 10%) to identify the bacterial species population. In contrast, the 26S rDNA pyrosequencing was performed only on kefir grains with the aim of assessing the yeast populations. In parallel, pH measurements were performed on the kefir obtained from the kefir grains using 2 incorporation rates. Regarding the bacterial population, 16S pyrosequencing revealed the presence of 20 main bacterial species, with a dominance of the following: Lactobacillus kefiranofaciens, Lactococcus lactis ssp. cremoris, Gluconobacter frateurii, Lactobacillus kefiri, Acetobacter orientalis, and Acetobacter lovaniensis. An important difference was noticed between the kefir samples: kefir grain purchased from a supermarket (sample E) harbored a much higher proportion of several operational taxonomic units of Lactococcus lactis and Leuconostoc mesenteroides. This sample of grain was macroscopically different from the others in terms of size, apparent cohesion of the grains, structure, and texture, probably associated with a lower level of Lactobacillus kefiranofaciens. The kefir (at an incorporation rate of 5%) produced from this sample of grain was characterized by a lower pH value (4.5) than the others. The other 4 samples of kefir (5%) had pH values above 5. Comparing the kefir grain and the kefir, an increase in the population of Gluconobacter in grain sample B was observed. This was also the case for Acetobacter orientalis in sample D. In relation to 26S pyrosequencing, our study revealed the presence of 3 main yeast species: Naumovozyma spp., Kluyveromyces marxianus, and Kazachastania khefir. For Naumovozyma, further studies are needed to assess the isolation of new species. In conclusion, this study has proved that it is possible to establish the patterns of bacterial and yeast composition of kefir and kefir grain. This was only achieved with the use of high-throughput sequencing techniques. Key words: kefir, microbiota, metagenetics, 16S rRNA sequencing, 26S rRNA sequencing Short CommunicationOriginally from the Caucasus Mountains (Otles and Cagindi, 2003), kefir is widely consumed in Eastern Europe but now encountered all over the world. The word "kefir" means "good feeling" in Turkish, due to the cooling nature of this beverage. The kefir beverage is produced by mixing milk, water, or fruit juice with kefir grains, which have the appearance of small cauliflowers (Lopitz-Otsoa et al., 2006). These grains are a symbiotic combination of bacteria (mainly lactob...

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“…Kefir grains has also been used for fermentation of milk and fruits (Magalhães et al, 2010;Nalbantoglu et al, 2014). Kefir is a beverage prepared by kefir grains fermentation in different substrates and is a combination of yeasts and bacteria's in a symbiotic polysaccharide matrix (Puerari et al, 2012 Guedes et al, 2014).…”

Section: Introductionmentioning

confidence: 99%

“…Kefir is a beverage prepared by kefir grains fermentation in different substrates and is a combination of yeasts and bacteria's in a symbiotic polysaccharide matrix (Puerari et al, 2012 Guedes et al, 2014). The microorganisms present in kefir grains are non-pathogenic bacteria and yeasts (Magalhães et al, 2010;Nalbantoglu et al, 2014). In general, fermentation process has been shown to preserve food with modification of physicochemical properties of foods but also provide impact on the raw material functional quality (Ahmed et al, 2013;Altay et al, 2013).…”

Section: Introductionmentioning

confidence: 99%

Microorganisms in functional food supplementation: A review

Magalhães-Guedes¹,

Ferreira²,

Magalhães³

et al. 2017

Afr. J. Microbiol. Res.

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Use of microbial systems for functional foods supplementation can be defined into fermentative process by starter cultures, use of probiotics microorganisms and use of microbial biomass. Scientific and technical aspects as related to use of microorganisms in functional foods supplementation are highly diverse and complex, since they have to deal with the viability of probiotic strains as well as with the safe production, nutritional composition and acceptability of the new product. However, limited information is available on the microorganisms which can be used in functional food supplements, as well as how to use these microorganisms and generation of products. This review reports details of this information. The data from this review can be useful to support the development of new functional products, with microbial supplementation, for the market.

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Metagenomic analysis of the microbial community in kefir grains

Cited by 137 publications

References 39 publications

A review: chemical, microbiological and nutritional characteristics of kefir

A review: chemical, microbiological and nutritional characteristics of kefir

Short communication: Evaluation of the microbiota of kefir samples using metagenetic analysis targeting the 16S and 26S ribosomal DNA fragments

Microorganisms in functional food supplementation: A review

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