Water Kefir: Review of Microbial Diversity, Potential Health Benefits, and Fermentation Process

Abstract

Water kefir is a non-dairy fermented beverage that ferments water kefir grains in a sucrose solution. These grains harbor a diverse microbiota, including lactic acid bacteria, acetic acid bacteria, and yeast species. The composition of water kefir is primarily influenced by cultivation conditions and the microbiota profile of the grains, resulting in fermentation metabolites such as ethanol, lactic acid, mannitol, acetic acid, glycerol, and other organic acids. However, this microbial diversity can vary depending on the origin of the grains, the fermentation substrate, and environmental conditions. As it is a potentially beneficial product for health, interest in kefir consumption has increased in recent years. Specific legislation for water kefir is still scarce, and despite potentially probiotic microorganisms, water kefir is not classified as a probiotic, but it fits the definition of a potentially functional food due to its health benefits. Studies demonstrate the potential health benefits of water kefir in terms of anti-inflammatory, antimicrobial, antioxidant, antidiabetic, and intestinal health effects. However, industrial-scale production and starter cultures have not yet been developed. This study aims to comprehensively review water kefir, exploring its potential health benefits, fermentation process, microbial diversity, and regulatory aspects.

1. Introduction

In recent years, consumer demand for nutritionally rich foods that support health and enhance quality of life has significantly increased [1]. Due to the growing awareness of the health benefits of probiotics, there is a rising interest in foods containing microorganisms with probiotic properties, with fermented foods gaining particular attention [2].

Dairy-based fermented foods remain the most prevalent among fermented foods. However, plant-based alternatives have garnered significant interest, whether due to health issues, such as people with allergies related to protein in cow’s milk or lactose intolerance, or the growing number of vegans [1,3]. Thus, within the group of non-dairy fermented foods, we have water kefir [4].

Water kefir is obtained by fermenting water kefir grains inoculated in a sucrose solution, with brown sugar being the primary fermentation agent [4]. The fermented beverage obtained is carbonated, cloudy, mildly alcoholic, and sweet. Its composition is determined mainly by the cultivation conditions and the microbiological profile of the grains, with the main fermentation byproducts including ethanol, lactic acid, mannitol, acetic acid, glycerol, and other organic acids [5,6]. The great variability in the microbiological composition of this fermented beverage makes it difficult to include it as a probiotic beverage, creating an important area that needs to be explored [7].

The health benefits of water kefir consumption may stem from its beneficial microorganisms, fermentation metabolites (organic acids and oligosaccharides), or their synergistic effects. However, studies on water kefir are scarce, and further research is needed to fully understand its potential health benefits [8]. Associated with this, it is necessary to explore and identify the microorganisms found in water kefir so that we can understand its composition, favoring the formulation of specific legislation for this beverage and the complete understanding of the real benefits associated with health [9,10]. Additionally, studies are needed on alternatives for preserving the microorganisms present in this beverage, and other products need to be made available to the consumer that are practical without losing the benefits. Therefore, the major gaps that need to be filled are based on conducting clinical studies with humans to verify the real effect of water kefir on human metabolism, and the development of starter cultures, facilitating the standardized determination of the microbial diversity of water kefir, and legislation [8].

In this context, this study aims to conduct a review of water kefir, exploring the fermentation process that occurs in the production stage of this beverage, the microorganisms identified, the potential health benefits, and the current regulatory aspects. For this purpose, a search of the current literature was carried out using the following keywords: water kefir, sweet kefir, tibicos, tibi, and non-dairy kefir.

2. Origin, Composition, and Production Process

The origin of water kefir is mostly unknown, unlike that of milk kefir. There is no documented region of origin for water kefir. Still, the first scientific report was published in 1889, which related the use of kefir grains in beer made with ginger by soldiers in the Crimean War in 1855 [5,11]. In 1989 in Mexico, water kefir was described as a microbial community called “tibi”. Other reports relating the use of water kefir were made in Mexico, France, Italy, and Germany; however, they used different names for the grains, such as tibicos, tibi, sweet kefir, Piltz, and kefir di Frutti, among others [5,11,12]. The consumption of water kefir is more common in countries as Russia, South America, and Eastern Europe, where it is traditional [7,11]. Information on availability suggests that water kefir is produced and consumed across several continents. This indicates a widespread and growing interest in this fermented beverage. Future research and market analysis may provide more concrete production.

The structure of water kefir grains is formed by α-D-(1→6)-linked glucopyranosyl residues with (1→3) connected side chains. The grains range in size from 5 to 20 mm in diameter, are irregular in shape, translucent, have a fragile structure, and are insoluble in water. The color of water kefir grains ranges from whitish to gray. Still, it can be influenced by the fermentation material, for example, the color of the fruits or vegetables, or the type of sugar used [11,13,14,15,16].

The grains can be reused for multiple fermentations through back-slopping, or by transferring them from a previous batch to a fresh substrate for a new fermentation [11,12]. Several fruits and vegetables, including soy, ginger, carrot, apple, pineapple, grape, kiwi, pear, melon, strawberry, pomegranate, tomato, and coconut, have been used as fermentation substrates, offering options for diversification and nutritional enhancement [5,17,18,19].

The resulting fermented beverage is carbonated, slightly cloudy, mildly alcoholic, and sweet. The grain cultivation conditions and microbiological profile primarily influence its composition. The main fermentation byproducts include ethanol, lactic acid, mannitol, acetic acid, glycerol, and other organic acids [5,6]. Thus, the beverage obtained after the fermentation process is composed of microorganisms (a symbiotic community of bacteria and yeasts), 2% lactic acid, 1% acetic acid, small amounts of alcohol resulting from the fermentation process (1%), and carbon dioxide, and the initial sugar content is reduced by half. Studies show that the concentration of microorganisms in the beverage may vary due to previously mentioned factors. The proportion of lactic acid bacteria ranges from 2.8 × 10⁴ to 9 × 10⁷ CFU/mL, acetic acid bacteria from 7 × 10² to 3.2 × 10⁶ CFU/mL, and yeasts from 4.7 × 10⁵ to 4.8 × 10⁷ CFU/mL. The beverage resulting from the fermentation process contains various aromatic compounds, including isoamyl acetate, ethyl acetate, and ethyl octanoate, among others [11,20].

Fermentation is typically spontaneous, involving water kefir grains in a sucrose solution. Traditionally, water kefir fermentation occurs by incubating the mixture at 20–25 °C in a dark environment for 24–72 h, using 6–30% sugar and 6–20% water kefir grains [14,21]. Standardized starter cultures are uncommon, and water kefir is usually produced domestically, making it more challenging to standardize the beverage [11]. After separating the water kefir grain from the fermented liquid, the liquid can be consumed as is or used in a second fermentation to enhance flavor and naturally carbonate the drink [5,22]. Figure 1 and Figure 2 summarize the water kefir production process.

Water kefir has been growing in popularity due to its potential health benefits. For this reason, studies have been carried out to obtain new products that are easier to apply and meet the needs of the consumer market for more practical foods. Among these is the development of powdered water kefir. A study demonstrated that microorganisms were preserved in water kefir even after the freeze-drying process, maintaining the product’s characteristics and showing the versatility of water kefir [23]. Additionally, water kefir is a refreshing and carbonated beverage and can be an alternative to replacing the consumption of soft drinks, which are nutritionally poor products. Thus, kefir could be a beverage that appeals to consumers due to its organoleptic characteristics, while also offering added nutritional value. Furthermore, research has been conducted to use water kefir as an ingredient in the formulation of other products to enhance nutritional value by providing more potentially beneficial microorganisms [24].

3. Regulatory Aspects

Several studies have reported that fermented foods offer potential health benefits, as the International Scientific Association for Probiotic and Prebiotic (ISAPP) reported. Still, they cannot be classified as probiotic foods. Although kefir contains microorganisms in its composition, to be considered probiotic, the species responsible for the beneficial effects must be isolated and identified, and their action must be scientifically proven. Additionally, it is difficult to determine whether the beneficial effects of consuming fermented foods are related to microorganisms, the food matrix, or a combination of both, associated with the fact that changes in the microbial species may occur over the shelf life of fermented foods, making it difficult to determine the composition of microorganisms in fermented foods accurately. Therefore, traditional fermented foods must use the term “containing live and active bacterial cultures” [4,25].

Water kefir is regulated in some countries and is commonly marketed as a “traditional beverage”. In Brazil, legislation regarding fermented beverages does not include specific regulatory provisions for water kefir, and regulations focus exclusively on milk kefir, as established in the Technical Regulation for the Identity and Quality of Fermented Milk. There is no specific legislation for non-dairy fermented products. Still, it is determined that fermented products must maintain their activity and abundant viability in the product throughout their shelf life. Previous legislation determined that the total bacterial count must reach at least 10⁷ CFU/mL for LAB and at least 10⁴ CFU/mL for yeasts in vegetable beverages. However, the current legislation only determines the quantity of microorganisms that must be mentioned and effective [26]. In Japan, kefir can be marketed as a functional beverage, but it must meet the Foods for Specified Health Uses (FOSHU) criteria if it claims to confer health benefits [9].

Although not classified as a probiotic food, water kefir demonstrates notable health-benefiting activity, aligning with the definition of functional food. Functional foods are natural or processed foods that contain biologically active compounds that offer clinically proven health benefits in defined, effective, and non-toxic quantities. These benefits are supported by specific biomarkers for preventing, managing, or treating chronic diseases or their symptoms [27]. Thus, water kefir is a potentially functional food due to its characteristics and potential health benefits [4,21].

4. Fermentation Dynamics of Water Kefir

Water kefir presents a challenging environment, rich in sugar and low in nitrogen (amino acids), making cooperation among the microbial community crucial. During fermentation, the metabolic activities of yeast and bacteria produce various compounds that contribute to the aroma and functional properties of the final products. When microorganisms in water kefir grow under optimal conditions, dextran—the main structural component of kefir grains—is synthesized, increasing grain biomass [5,11,28].

The water kefir fermentation process starts aerobically and gradually becomes anaerobic as oxygen is consumed and/or eliminated by the carbon dioxide produced by the yeasts [11,28]. Sucrose is metabolized into ethanol, carbon dioxide, lactic acid, acetic acid, mannitol, vitamins (e.g., B vitamins), amino acids (e.g., arginine), glycerol, esters, and other organic acids. In this way, the sucrose concentration decreases by up to 98% in the first 24 h of fermentation [10,11,29].

In the common dynamics of water kefir fermentation, yeasts such as Saccharomyces, Zygotorulaspora and Dekkera hydrolyze sucrose through an extracellular β-D-fructofuranosidase (invertase), producing glucose and fructose. These monosaccharides are absorbed by the yeast cells through facilitated diffusion. Yeast uses these sugars for its metabolism and ethanol production, making them available to the bacteria. The ethanol concentration increases linearly until it exceeds 10% of the total volume. However, the ethanol level decreases as it is converted into acetic acid by acetic acid bacteria during fermentation [11,30].

Although lactic acid bacteria are more abundant in the grains, yeast-driven metabolic activity predominates during water kefir fermentation. Some studies suggest a potential relationship between the CO₂ released by the yeast and the stimulation of lactic acid bacteria. In the early stage of fermentation, small amounts of CO₂ may stimulate the growth of lactic acid bacteria, producing organic acids that acidify the medium and can be used by yeast as an energy source [14].

Other microbial interactions may occur during kefir fermentation. However, separate cultures of microbial kefir grains do not grow in sugar solution or have decreased biochemical activity, making studying the microbial interactions involved in kefir fermentation even more challenging [5].

5. Microbial Diversity of Water Kefir

The microbiota of water kefir grains includes various species of lactic acid bacteria (LAB), acetic acid bacteria (AAB), and yeast. Each gram of water kefir grain contains approximately 10⁸ colony-forming units (CFU) of LAB, 10⁶–10⁸ CFU of AAB, and 10⁶–10⁷ CFU of yeast [6,31]. LAB are primarily represented by the genus Lactobacillus, AAB by the Acetobacter genus, and yeasts by the Saccharomyces, Zygosaccharomyces, and Brettanomyces genera. The dominant species and their prevalence in studies can vary based on several factors, including the substrate used and fermentation conditions. Additionally, the origin of the grains and diversity of the samples studied can influence the species commonly isolated [6,29]. The composition and frequency of microbial species, and the concentration of bioproducts, depend on the carbon and energy sources available during fermentation, which also affects grain granulation and microbial growth [32].

Different species within water kefir exhibit symbiotic relationships, surviving and propagating by sharing their bioproducts as energy sources or growth-stimulating factors. It has been shown that the composition of the water kefir beverage differs in proportion to the grains from which it is obtained, depending on the type of fermentation substrate used [5]. The beverage’s composition can also vary during successive fermentations, even when the same grain is used on each substrate [33].

Since the discovery of these organisms and the subsequent development of molecular tools, significant steps have been taken to identify the variety of yeasts and bacteria involved in water kefir fermentation. Numerous studies on the microbiology of water kefir have been conducted across different countries [28]. Table 1 presents a microbiological diagnosis of the different species identified in water kefir from different countries.

A metagenomic study using the Shotgun technique in water kefir demonstrated Lactobacillus, Oenococcus, and Bifidobacterium as the main bacterial genera, and Saccharomyces and Dekkera as the main yeast genera. Additionally, it showed a possibly novel Lactobacillus species related to L. hordei and L. mali, and a novel Oenococcus sp., Candidatus O. aquikefiri [37].

A recent study using water kefir from Brazil demonstrated a greater abundance of Zymomonas mobilis, followed by Sporolactobacillus spathodeae and Liquorilactobacillus satsumensis. Regarding fungi, Lachances fermentati was the most present, followed by Wickerhamomyces anomalus [23].

Microorganisms with potential probiotic properties isolated from water kefir include Lactobacillus acidophilus LA15, Lactobacillus delbrueckii ssp. bulgaricus B-30892, Lactobacillus kefiranofaciens M1, L. kefiranofaciens DN1, L. lactis WH-C1, Lactobacillus mali APS1, Lacticaseibacillus paracasei CIDCA 8339, and Lactiplantibacillus plantarum MA2 [4,45,46].

Knowing the composition of microorganisms present in water kefir is extremely important. It helps in understanding the composition of this beverage, how these microorganisms can act, and their relationship with consumer benefits. It also helps standardize specific legislation for water kefir. Thus, a major gap that needs to be filled is the determination of starter cultures, which would favor greater standardization of the microbial diversity in water kefir.

6. Potential Health Benefits of Water Kefir

Fermented products, including water kefir, can provide beneficial effects (Figure 3) when consumed due to the content of beneficial microorganisms or compounds produced by these microorganisms [4]. Unlike milk kefir, few studies have evaluated the potential health benefits of water kefir, especially in humans. Despite this, studies demonstrate the benefits of water kefir, highlighting anti-inflammatory, antimicrobial, antioxidant, antidiabetic, and intestinal health-promoting effects [4,13].

Antidiabetic effects have been associated with water kefir, where administration to Wistar rats improved glucose levels and lipid profiles [47]. An in vitro study with cells demonstrated α-glucosidase inhibitory activity (50–80%) by water kefir [45]. Experiments with mice evaluating the administration of L. paracasei isolated from water kefir grains demonstrated that after 14 weeks, the experimental group presented less insulin intolerance and alteration of genes involved in glucose homeostasis [46].

Furthermore, administering water kefir for 2 weeks enhanced systemic antioxidant activity in mice, demonstrated by an increase in the activity of the enzymes superoxide dismutase and catalase. With this antioxidant activity, water kefir showed the ability to reduce gastric ulcers and improve protein oxidation in mice [48]. Water kefir also exhibits potential antimicrobial effects related to the compounds produced during fermentation, such as the production of organic acids, which reduce pH, inhibiting the growth of pathogenic microorganisms [28].

The potential beneficial effects of water kefir are linked to intestinal health. After administering water kefir to rats, it was found to have a protective effect against inflammation-induced intestinal barrier disruption. This effect was associated with an increased production of short-chain fatty acids (SCFAs) and Bifidobacterium species, and a reduction in excess proteolytic fermentation compounds [20]. SCFAs (propionate, butyrate, and acetate) are metabolites that the intestinal microbiota produces. They help maintain the integrity of the intestinal barrier, exert an anti-inflammatory effect, and promote the growth of beneficial bacteria [49].

Studies demonstrate the beneficial action of water kefir in improving intestinal microbiota composition. Microorganisms isolated from water kefir administered to rats increased the number of Firmicutes, Bacteroidetes, Lactobacillus, and Prevotella, and decreased that of Proteobacteria and Enterobacteriaceae. This selective alteration of the intestinal microbiota may be linked to the ability of probiotic strains to co-aggregate and form a protective barrier that prevents pathogenic bacteria from colonizing the epithelial surface. Additionally, these strains can produce antimicrobial substances, such as bacteriocins [50,51]. In animals supplemented with potentially probiotic microorganisms, improvements in the intestinal mucosal barrier were observed, which led to a decrease in translocation from the gastrointestinal tract to the bloodstream. This also reduced the production of Immunoglobulin E (IgE) associated with allergic reactions. The suppression of IgE occurred through the upregulation of Cd2, Stat4, and Ifnr expression, which induced a balanced Th1/Th2 response, increased the regulatory population of CD4(+) and CD25(+) T cells, and reduced the activity of CD19(+) B cells [52].

Despite the numerous benefits associated with the consumption of water kefir, it should be considered that in some situations, water kefir, as well as other fermented beverages, may not be recommended, such as for pregnant women, since the fermentation process results in the formation of alcohol [10,11,14]. Still, the beverage obtained has a considerable sugar content, which should be included in the diet of people with diabetes with caution. As discussed, water kefir is mainly produced in an artisanal manner, without rigorous industrial processes, which means that contamination can occur during the artisanal production process of water kefir [8].

Despite in vitro studies and animal model research demonstrating the potential benefits of consuming water kefir, clinical studies with humans are extremely important to establish its real effects on human metabolism. However, given the possible evidence of water kefir in relation to various pathological clinical conditions, water kefir may be classified as a probiotic food in the future. It could be utilized to prevent and treat various diseases [45].

7. Final Considerations and Future Perspectives

Water kefir is a potential functional food associated with health benefits and can meet the market demand for vegan foods. The fermented beverage obtained is principally composed of microorganisms, acetic acid, lactic acid, and ethanol. Microbiological diversity is influenced by the origin of the grains and the fermentation process, among other factors. Additionally, there is an urgent need to intensify research in starter cultures for water kefir production to enable the transition from artisanal to industrial production and allow for the standardized identification of microorganisms present in this beverage.

Author Contributions

All authors have contributed substantially to the work reported. All authors have read and agreed to the published version of the manuscript.

Data Availability Statement

The data are contained within this article.

Acknowledgments

The authors are grateful to the Postgraduate Program in Food Science and Technology, Center of Agricultural Sciences and Engineering, Federal University of Espírito Santo, and to the Department of Food Science and Technology, Federal University of Santa Catarina, Florianópolis 88034-001, Santa Catarina, Brazil, for their partnership and support in our research on water kefir.

Conflicts of Interest

The authors declare no conflict of interest.

Footnotes

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Figures and Table

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Figure 1. Stages of water kefir production: first fermentation process.

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Figure 2. Stages of water kefir production: second fermentation process.

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Figure 3. Health benefits of water kefir based on in vivo and in vitro studies.

Table 1

Microorganisms identified in water kefir.

Origin of Grains	Region Analyzed	Primers	Bacteria Species	Yeast Species	Reference
Brazil	16S rRNA	338fgc and 518r/NS3 and YM951r	Lentilactobacillus parabuchneri, Lentilactobacillus kefiri, Lactobacillus lactis, Lacticaseibacillus casei, Leuconostoc citreum, Lacticaseibacillus paracasei subsp. paracasei subsp. tolerans, Lentilactobacillus buchneri, Acetobacter lovaniensis.	Saccharomyces cerevisiae, Kluyveromyces lactis, Lachancea meyersii, Kazachstania aerobia.	[34]
China	16S rRNA/18S rDNA and ITS	27F and 1492R/NS1F and ITS4R	Leuconostoc pseudomesenteroides, Serratia liquefaciens, Pseudomonas fragi, Ochrobactrum lupini, Zymomonas mobilis, Lentilactobacillus hilgardii, Lactococcus raffinolactis, Leuconostoc mesenteroides.	Saccharomyces cerevisiae, Guehomyces pullulans.	[35]
Argentina	16/26S rDNA	7F and 1510R/LSU-D2F and LSU-D2R	Acetobacter indonesiensis, Acetobacter lovaniensis, Acetobacter tropicalis, Gluconobacter oxydans, Lacticaseibacillus casei/paracasei, Lentilactobacillus diolivorans, Lentilactobacillus farraginis, Lactobacillus harbinensis, Lentilactobacillus hilgardii, Lactobacillus nagelii, Liquorilactobacillus satsumensis, Oenococcus kitaharae.	Pichia membranifaciens, Pichia occidentalis, Saccharomyces cerevisiae.	[36]
Belgium	16S rRNA/ITS1 and ITS2	ND	Lactobacillus harbinensis, Lentilactobacillus hilgardii, Lactobacillus nagelii, Lacticaseibacillus paracasei subsp. paracasei, Liquorilactobacillus hordei, Bifidobacterium aquikefiri, Candidatus Oenococcus aquikefiri.	Saccharomyces cerevisiae, Dekkera bruxellensis.	[37]
China	16S rRNA/ITS	ND	Genus: Acetobacter, Lactobacillus, Ameyamaea, Nguyenibacter, Corynebacterium, Tanticharoenia, Acidomonas, Tetragenococcus, Ruminococcus, Bifidobacterium, Neokomagataea.	Saccharomyces cerevisiae, Candida kruisii, Candida ethanolica, Kazachstania humilis, Candida sake, Mortierella alpina, Candida elateridarum, Mortierella sarnyensis, Plectosphaerella cucumerina, Scytalidium cuboideum, Metarhizium anisopliae.	[38]
China	16S rRNA/ITS	PRK341F and PRK806R/ITS1	Genus: Acetobacter, Lactobacillus, Gluconobacter, Ameyamaea, Luteimonas, Atopobacter, Tanticharoenia, Swaminathania, Bifidobacteria, Nguyenibacter, Asticcacaulis, Swingsia.	Saccharomyces cerevisiae, Candida kruisii, Candida ethanolica, Dekkera bruxellensis, Kazachstania barnettii, Kazachstania humilis, Mortierella alpina, Rhizopus arrhizus, Saitozyma podzolica, Candida tetrigidarum, Dipodascus geotrichum, Clonostachys miodochialis, Ramularia pratensis, Bullera alba, Zopfiella marina, Chaetospermum chaetosporum.	[39]
Germany	16S rRNA	M13V and BOXA1R	Bifidobacterium tibiigranuli sp. nov.	ND	[40]
Brazil	16S rRNA/ITS	341F and 806R	Gluconobacter morbifer, Gluconobacter frateurii, Gluconobacter cerinus, Gluconobacter albidus, Gluconacetobacter liquefaciens, Leuconostoc mesenteroides, Leuconostoc carnosum, Liquorilactobacillus uvarum, Lactobacillus sakei, Liquorilactobacillus oeni, Liquorilactobacillus mali, Latilactobacillus curvatus, Acetobacter persici, Acetobacter peroxydans, Acetobacter pasteurianus, Acetobacter orientalis, Acetobacter lambici, Acetobacter indonesiensis.	Lasiodiplodia brasiliensis, Debaryomyces hansenii, Cladosporium herbarum, Cladosporium delicatulum, Lachancea fermentati, Pichia fermentans, Saccharomyces cerevisiae, Candida etchellsii.	[41]
Brazil	16S rRNA/ITS	ND	Liquorilactobacillus satsumensis, Oenococcus kitaharae, Oenococcus oeni, Gluconobacter oxydans, Acetobacter sp., Lactobacillus sp., Liquorilactobacillus oenit, Liquorilactobacillus nagelii, Komagataeibacter intermediust, Komagataeibacter saccharivorans, Gluconobacter cerinus.	Brettanomyces bruxellensis, Saccharomyces cerevisiae, Lachancea fermentati.	[22]
Argentina	16S rRNA	341F and 806R	Rothia mucilaginosa, Lawsonella clevelandensis, Gluconobacter oxydans, Enterobacteriaceae, Rahnella aquatilis, Staphylococcus gallinarum, Ligilactobacillus pobuzihii, Schleiferilactobacillus harbinensis, Liquorilactobacillus nagelii, Lactobacillus kefiranofaciens, Latilactobacillus sakei, Corynebacterium pyruviciproducens, Propionibacterium acnes, Pseudomonas migulae, Acetobacter lovaniensis, Fenollaria massiliensis, Liquorilactobacillus satsumensis, Oenococcus kitaharae, Lentilactobacillus hilgardii, Lacticaseibacillus casei/paracasei, Lactiplantibacillus plantarum, Lactococcus lactis.	ND	[33]
Switzerland	16S rDNA	ND	Zymomonas mobilis, Bifidobacterium aquikefiri, Liquorilactobacillus hordei, Liquorilactobacillus satsumensis, Liquorilactobacillus nagelii, Leuconostoc suionicum.	Brettanomyces bruxellensis, Saccharomyces cerevisiae, Saccharomyces eubayanus, Torulaspora delbrueckii.	[42]
Türkiye	16S rRNA	341F805R	Ligilactobacillus ruminis, Bacillus methanolicus, Acetobacter percisi, Amylolactobacillus amylophilus, Lactococcus sp., Achromobacterx ylosoxidans, Lentilactobacillus buchneri, Pediococcus pentosaceus, Melissococcus plutonio, Komagataeibacters accharivorans, Staphylococcus aureus, Marinilactibacillus sp., Lactobacillus sakei, Pseudomonas synxantha, Enterococcus faecium, Bacillus thuringiensis, Loigolactobacillus backii, Streptococcus sobrinus, Acetobacter persici, Bacillus amyloliquefaciens, Limosilactobacillus reuteri, LimosiLimosilactobacillus fermentum.	Pichia kudriavzevii, Saccharomyces cerevisiae, Eremothecium cymbalariae, Candida glabrata, Ogataea parapolymorpha, Thermothielavioides terrestris, Tetrapisispora phaffii, Fusarium oxysporum, Sugiyamaella lignohabitans, Aspergillus oryzae.	[43]
Türkiye	16S rRNA and 18S rRNA	341F and 806R/2024F and 2409R/528F and 706R	Lactobacillus nagelii, Lactobacillus harbinensis, Liquorilactobacillus ghanensis, Pseudomonas geniculate.	Geotrichum silvicola, Dekkera bruxellensis, Dekkera anomala, Lachancea fermentati.	[28]
Argentina	16S rRNA and 18S	P0 and P6/ITS1F and ITS4	Lentilactobacillus hilgardii, Lentilactobacillus buchneri.	Saccharomyces cerevisiae.	[44]
Brazil	16S rRNA	ITS1 and ITS2	Zymomonas mobilis, Sporolactobacillus spathodeae, Liquorilactobacillus satsumensis, Lactobacillus sp., Lentilactobacillus hilgardii, Oenococcus kitaharae, Acetobacter peroxydans, Gluconobacter frateurii, Leuconostoc mesenteroides.	Lachancea fermentati, Wickerhmomyces anomalus, Saccharomycetes sp., Saccharomyces cerevisiae, Torulaspora delbrueckii, Candida californica.	[23]

ND: Not Determined.

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