Saccharomyces exiguus

Saccharomyces exiguus (Kazachstania exigua): An Encyclopedic Reference

1. Identity, Nomenclature, and Taxonomy

Saccharomyces exiguus is a wild, ascomycetous yeast whose taxonomic history spans more than a century of reclassification. The species was formally described by Saccharomyces exiguus Reess ex E.C. Hansen, published in Comptes-Rendus des Travaux du Laboratoire Carlsberg in 1888. In 2003, following phylogenetic analysis based on multigene sequencing, taxonomist C.P. Kurtzman transferred the species to a newly circumscribed genus: the species became Kazachstania exigua (Reess ex E.C. Hansen) Kurtzman comb. nov., with Saccharomyces exiguus Reess ex E.C. Hansen as its basionym. This reclassification was published in FEMS Yeast Research 4(3): 233–245 (2003).

The genus Kazachstania was validly described by Zubkova in 1971 and therefore has taxonomic priority over Arxiozyma van der Walt & Yarrow (1984) and Pachytichospora van der Walt (1978), two closely related monotypic genera. Species of this clade that were previously assigned to Saccharomyces or Kluyveromyces were transferred to Kazachstania because they are not members of either genus as now defined by molecular phylogeny.

As a result of this history, Saccharomyces exiguus carries numerous accepted synonyms. Its confirmed synonyms include Candida holmii (A.Jörg.) S.A.Mey. & Yarrow; Cryptococcus holmii (A.Jörg.) C.E.Skinner; Saccharomyces exiguus Reess; Saccharomyces exiguus Reess ex E.C. Hansen; Torula holmii A.Jörg.; Torulaspora exigua Kock.-Krat.; and Torulopsis holmii (A.Jörg.) Lodder. In older literature, especially in studies of sourdough fermentation, the anamorph (asexual form) name Candida holmii appears frequently alongside the teleomorph S. exiguus.

At the most current level of classification, the NCBI Taxonomy Browser additionally places this organism within the genus Maudiozyma, listing Kazachstania exigua Kurtzman, 2003 as a synonym, under the family Saccharomycetaceae within Saccharomycetales. The full classification is: Kingdom Fungi; Phylum Ascomycota; Class Saccharomycetes; Order Saccharomycetales; Family Saccharomycetaceae.

A notable taxonomic complication is that isolates formerly grouped under the name S. exiguus are genetically heterogeneous. Isolates previously described as S. exiguus showed a high degree of polymorphism; only one (CBS 1514) of ten studied isolates had a sequence identical to that of the type strain NRRL Y-12640. This heterogeneity reflects decades of phenotype-based classification in which minor physiological differences were accepted as sufficient grounds for species-level distinction.

2. Natural Sources and Ecology

Ecologically, S. exiguus / K. exigua is a wild yeast found on plants, fruits, and grains. It is commonly found in diverse environments including grapes, strawberries, soil, sewage, and sourdough, and is believed to have been originally isolated from wheat sourdough in Umbria, Italy.

Kazachstania exigua is a GRAS (Generally Recognized As Safe) yeast isolated from different food sources, including sourdough, kefir grains, and mezcal. It has been reported in wine, although its occurrence there is rare. Its presence in mezcal fermentation has also been documented: in a study on mezcal fermentations of Agave salmiana, Saccharomyces exiguus was detected alongside S. cerevisiae, K. marxianus, Pichia kluyveri, Zygosaccharomyces bailii, and other yeasts.

In kefir, Saccharomyces exiguus is listed among the non-lactose-fermenting yeasts of kefir grains, alongside Saccharomyces unisporus and Saccharomyces cerevisiae.

3. Traditional and Historical Use

3.1 Sourdough Bread Fermentation

The most historically significant context for S. exiguus is sourdough bread production, which represents one of humanity's oldest biotechnological processes. The use of the sourdough process is one of the oldest spontaneous biotechnological processes in cereal food production. Although ancient bakers had no knowledge of the specific yeast species driving fermentation, they continuously maintained and propagated living cultures that, we now know, frequently harbored this organism.

The most common yeast species in sourdough are Kazachstania exigua (syn. Saccharomyces exiguus), Saccharomyces cerevisiae, K. exiguus, and K. humilis (previously Candida milleri or Candida humilis). Among sourdough fermentations, the most representative species of lactic acid bacteria and yeasts are, respectively, Lactobacillus sanfranciscensis and Saccharomyces exiguus.

Traditional sourdoughs used as the sole leavening agent are referred to as Type I sourdough; examples include those used for San Francisco Sourdough Bread, Panettone, and rye bread. Type I sourdoughs are generally firm doughs, have a pH range of 3.8 to 4.5, and are fermented in a temperature range of 20 to 30°C (68 to 86°F). The yeast Saccharomyces exiguus / Kazachstania humilis / Candida holmii usually populates sourdough cultures symbiotically with Fructilactobacillus sanfranciscensis.

Leavened bread was traditionally made with flour, water, and a fermenting agent, which was either a fermenting beverage or a fermenting dough, termed sourdough. This sourdough was generally initiated from a mixture of flour and water, naturally colonized by lactic acid bacteria and yeasts. Sourdough was either maintained from one bread-making process to the other or initiated again.

Geographically, the use of sourdough cultures harboring S. exiguus spans multiple continents and traditions. In northern Europe, sourdough is employed mainly in the baking process of rye flour. In the Mediterranean area, sourdough bread is mainly produced in artisanal bakeries producing traditional breads, such as PDO breads including Pane di Altamura and Pagnotta del Dittaino. Durum wheat flour is used in southern Italy, the Middle East, and Arab countries to produce sourdough for loaf breads and leavened flat breads.

3.2 Kefir and Other Fermented Foods

Beyond bread, S. exiguus has been documented in traditional fermented dairy beverages. In kefir grains, it coexists within a consortium of lactic acid bacteria and other yeasts. The typical sourdough yeasts are Saccharomyces exiguus (current name: Kazachstania exigua) and Candida humilis. The presence of S. exiguus in mezcal production, as described in studies of Oaxacan fermentations, reflects a broader role in traditional alcoholic beverage production from plant materials.

3.3 Wine

Kazachstania exigua is a GRAS yeast isolated from different food sources including sourdough, kefir grains, and mezcal. Its potential use in wine production has been explored: strains were tested in monoculture and in multistarter fermentation with Saccharomyces cerevisiae. Results showed interesting properties, including higher production of glycerol, changes in aromatic profile, and reduction of ethanol content in wines obtained.

4. Morphological and Physiological Characteristics

Colonies of K. exigua are smooth and round; their color varies from white to cream and they tend to have a butyrous texture. The organism reproduces by multipolar budding, characteristic of the broader Saccharomyces complex. Multipolar budding, production of ascospores, and fermentation profile aid in identification of Saccharomyces and related genera.

Metabolically, S. exiguus / K. exigua produces acid and uses (NH₄)₂SO₄ as a primary source of nitrogen. It can assimilate galactose, sucrose, and trehalose (variable: raffinose, lactate, succinate, ethanol); it shows no assimilation of nitrate or nitrite, no use of ethylamine, lysine, or cadaverine as sole nitrogen sources, and requires biotin and/or thiamin and/or pantothenate as vitamins. In liquid growth, it is non-flocculent, with no pellicle formation and no ring growth.

K. exigua is specifically known for fermenting D-glucose, D-galactose, and sucrose. Critically for its sourdough ecology, it appears unable to ferment maltose — a property it shares with related Kazachstania species. K. exigua is valuable because it is an acid-tolerant yeast, unlike many commercial yeasts, which are threatened in the acidic environment created by lactic acid bacteria during fermentation. Worldwide, a diversity of yeast species is encountered in sourdough, with Saccharomyces cerevisiae, Candida humilis, Kazachstania exigua, Pichia kudriavzevii, Wickerhamomyces anomalus, and Torulaspora delbrueckii among the most common ones. Sourdough-adapted yeasts are able to withstand stress conditions including nutrient starvation, acidic conditions, oxidative stress, thermal stress, and osmotic stress.

5. Key Constituents and Mechanisms of Action

5.1 Fermentation Products: CO₂ and Ethanol

The overall fermentation process involving K. exigua calls for the metabolizing of sugars with the production of carbon dioxide and alcohol as byproducts. Yeast cells ferment the carbohydrates present in the dough and generate carbon dioxide, which is responsible for dough leavening during the fermentation phase and the oven rise. These yeast species all ferment hexoses in the absence and presence of oxygen and thus convert carbohydrates into ethanol, carbon dioxide, and acetic acid.

5.2 Phytase Activity and Mineral Bioavailability

K. exigua produces phytase enzymes, which degrade phytic acid — a key antinutritional factor in cereal grains. Studies isolating phytase-active yeasts from Danish and Lithuanian sourdoughs identified Kazachstania exigua among the active species; tests were carried out under conditions optimal for bread leavening (pH 5.5, 30°C), and all isolates exhibited phytase activities. Phytic acid-degrading enzymes (phytases) break phosphomonoester bonds; phytase is endogenously found in cereals, legumes, and microorganisms including lactic acid bacteria. Phytase degrades phytic acid to lower inositol phosphate esters and inorganic phosphate.

Phytates negatively impact the bioavailability of divalent and trivalent mineral ions such as Zn²⁺, Mg²⁺, Ca²⁺, Mn²⁺, Cu²⁺, Fe²⁺, and Fe³⁺ due to their strong negative charge across a wide pH range. By degrading phytic acid during sourdough fermentation, yeasts including K. exigua thereby increase the dietary bioavailability of these minerals. The acidification process in sourdough indirectly stimulates both the innate phytases in the flour and microbial enzyme activity, resulting in a significant increase in mineral bioavailability.

5.3 FODMAP Reduction

FODMAPs (fermentable oligo-, di- and monosaccharides and polyols) are susceptible to fermentation by baker's yeast and lactic acid bacteria from sourdough. Fructans — the primary FODMAPs in wheat — are not degraded in simulated sourdoughs without microbial activity, but invertase activity of S. cerevisiae and related Kazachstania species results in partial hydrolysis of flour fructans. This mechanism is relevant to individuals sensitive to FODMAPs, such as those with irritable bowel syndrome. Sourdough fermentations partially or completely degrade FODMAPs in wheat and provide more time and more suitable conditions for wheat aspartic proteases, which are optimally active at low pH, to degrade wheat proteins.

5.4 Gluten Modification and Proteolysis

Sourdough fermentation alters the composition and activity of wheat proteins, reducing pH to the optimum of endogenous cereal proteases and thus stimulating proteolysis. Sourdough fermentation has emerged as a promising biotechnological approach to reducing gluten content and modifying gluten proteins in wheat-based products; the scientific literature specifically focuses on enzymatic degradation and hydrolysis of gluten during lactic acid bacteria (LAB) sourdough fermentation. The role of sourdough yeasts such as K. exigua in this process is indirect: their acid production lowers dough pH, creating conditions favorable for protease activity and gluten structure modification.

5.5 Microbial Mutualism in Sourdough Consortia

San Francisco sourdough harbors a microbial consortium of Fructilactobacillus sanfranciscensis and Kazachstania humilis that results from nutritional mutualism and mutual stress responses. A similar mutualistic dynamic characterizes K. exigua-containing consortia: the yeast's inability to ferment maltose is a key ecological advantage, as it means K. exigua does not compete with maltose-positive heterofermentative lactic acid bacteria for carbon sources. A higher maltose depletion was shown in maltose-negative Kazachstania and maltose-positive obligately heterofermentative LAB cocultures compared to monocultures.

Natural sourdough is made from flour and water and maintained by recurrent addition of flour and water (a process called backslopping). Sourdough contains a microbial community consisting of lactic acid bacteria and yeasts with a ratio of approximately 100:1 on average.

6. Common Forms and Preparations

S. exiguus / K. exigua is not sold as a standalone dietary supplement in isolated form. It is encountered and consumed almost exclusively as a component of traditional fermented foods and beverages. The principal preparations in which it is present include:

• Type I sourdough starter cultures: Type I sourdoughs, which are used as the sole leavening agent, include those used for San Francisco Sourdough Bread, Panettone, and rye bread. These are maintained as live, active cultures of mixed bacteria and yeasts, propagated by backslopping.
• Commercial starter preparations: Together with acidifying lactic acid bacteria, yeasts including K. exigua play a key role in sourdough production, where they are either naturally present or added as a starter culture.
• Kefir grains: Kefir grains exhibit an irregular, multilobular, and gelatinous structure, consisting of a symbiotic consortium of lactic acid bacteria, acetic acid bacteria, and yeasts. S. exiguus is one of the non-lactose-fermenting yeasts documented in some kefir grain preparations.
• Traditional alcoholic beverages: Mezcal and, rarely, wine. In wine, its occurrence is rare.
• Sourdough bread (baked product): While much of the yeast is inactivated during baking, the metabolic products (organic acids, modified proteins, reduced antinutrients) persist in the finished bread.

7. Scientific Evidence by Area of Use

Important framing note: The scientific literature on S. exiguus / K. exigua addresses it almost entirely as a component of sourdough fermentation systems — not as an isolated ingredient. Most health-relevant evidence relates to sourdough as a food matrix, and it is not possible to attribute effects specifically and solely to this yeast species. It is invariably studied in mixed-culture environments alongside lactic acid bacteria and other yeasts.

7.1 Glycemic Response and Carbohydrate Metabolism

The most extensively studied health-related outcome of sourdough consumption — the matrix in which K. exigua is among the key yeasts — is its effect on postprandial blood glucose. A systematic review investigated the clinical evidence on the effects of sourdough bread consumption on various health measurements relative to other sources of bread. The review included 25 interventional clinical trials, mostly on healthy subjects, using commercial sourdough breads or laboratory-made sourdough. The main health parameters assessed were glycemic response, satiety, and gastrointestinal and cardiovascular health.

In weighing the evidence, it is currently not possible to conclude that using sourdough instead of baker's yeast for fermentation during bread making would be sufficient to produce significant benefits on health in a clinical setting. More than 50% of the studies comparing sourdough bread with white wheat bread did not find significant differences in the glycemic response of healthy individuals.

Overall, it is currently difficult to establish a clear consensus with regard to the beneficial effects of sourdough on health compared with other types of bread because a variety of factors — including the microbial composition of sourdough, fermentation parameters, cereals, and flour types — potentially influence the nutritional properties of bread. Nonetheless, in studies using specific strains and fermentation conditions, significant improvements were observed in parameters related to glycemic response, satiety, or gastrointestinal comfort after bread ingestion.

Effects of sourdough bread when measured in vivo may be too small to result in significant changes. A recent meta-analysis of studies investigating the effect of sourdough fermentation on the glycemic index of bread provided no convincing evidence of positive effects. A health claim related to the reduction of post-prandial glycemic responses by high-fiber rye sourdough bread was not approved by EFSA because the supporting studies demonstrated a reduced glycemic response relative to glucose solutions but not to comparable bread produced without sourdough.

Sourdough fermentation significantly improves bread quality in various ways: it slows down starch digestion, leading to a reduced glycemic response, enhances protein digestion, and boosts the absorption of minerals.

Evidence strength: Weak to moderate for glycemic response in healthy individuals; no consistent benefit demonstrated in well-controlled clinical trials for the sourdough process per se.

7.2 Mineral Bioavailability and Nutritional Benefit

Research has indicated that phytic acid degradation in sourdough bread increases the bioavailability of minerals, free amino acids, and protein. The fermentation process reduces anti-nutrients such as phytates and increases beneficial phytochemicals. Some research indicates that sourdough bread has more phenols, carotenoids, folates, and other beneficial compounds than unfermented bread.

The mechanistic basis for these findings is well-established at laboratory level: the optimal pH range for achieving over 70% phytic acid degradation is usually between 4.3 and 4.6, and in the acidic environment created during sourdough fermentation, phytase activity is usually rapid. While the optimal pH for wheat phytase is 5.0, yeast phytase functions optimally at pH 3.5. K. exigua has been directly identified as a phytase-active organism in sourdough, as noted in the isolation studies above.

Evidence strength: Mechanistic evidence is strong; direct clinical evidence specifically attributable to K. exigua is not available. Phytic acid reduction by sourdough fermentation as a whole is well-supported at the food chemistry level.

7.3 Digestive Health and FODMAP Reduction

The implications of sourdough fermentation for individuals with gluten-related disorders, including celiac disease, non-celiac gluten sensitivity and intolerance, as well as irritable bowel syndrome (IBS), have been investigated in the scientific literature.

Sourdough fermentation does not eliminate gluten proteins that trigger celiac disease, but the use of sourdough processes in bread making can be an alternative to gluten-free diets to reduce symptoms associated with non-celiac wheat sensitivity. Mixed cultures of lactic acid bacteria degrade gluten peptides more effectively than monocultures. However, LAB sourdough fermentation is not sufficient to remove toxic peptides to the minimal level of less than 20 ppm required for a food to be considered safe for celiac disease patients under EU and international standards.

Regarding FODMAPs specifically, sourdough fermentation — through yeast invertase activity — partially degrades wheat fructans, the main FODMAP fraction. FODMAPs are susceptible to baker's yeast and LAB from sourdough fermentation. The contribution of K. exigua versus other sourdough yeasts to this process has not been individually quantified in clinical literature.

Evidence strength: Preliminary. Sourdough fermentation's effects on FODMAPs and gluten are mechanistically plausible and supported by in vitro and food chemistry studies; clinical evidence attributable specifically to K. exigua is absent.

7.4 Wine and Food Aroma / Quality

In the context of wine and fermented food production, K. exigua has been explored as a non-conventional yeast starter. Strains of K. exigua were tested in monoculture and multistarter fermentation with S. cerevisiae. The results showed interesting properties when used in multistarter inoculation, including production of higher amounts of glycerol, changes in aromatic profile, and reduction of ethanol content in the wines obtained. These preliminary results represent food technology research rather than human health evidence.

Evidence strength: Preliminary food-technology evidence only; no clinical health evidence in this domain.

7.5 Sourdough and Cardiovascular Health

Among the 25 clinical trials included in the systematic review on sourdough (total of 542 individuals), the main outcomes investigated were glucose response (N = 15), appetite (N = 3), gastrointestinal markers (N = 5), and cardiovascular markers (N = 2). The very small number of cardiovascular studies, and the fact that none are specifically attributable to K. exigua, makes it impossible to draw specific conclusions about cardiovascular benefits of this yeast.

Evidence strength: Insufficient; cardiovascular outcomes were assessed in only two of the retrieved sourdough clinical trials and no trial specifically evaluated K. exigua.

8. Body Systems and Health Areas of Association

Based on its established role in sourdough fermentation and the documented biological effects of sourdough fermentation as a food process, S. exiguus / K. exigua is associated — as a contributor to a fermentation consortium — with the following body systems and health areas:

• Digestive/Gastrointestinal System: Through production of organic acids, reduction of antinutrients, and partial FODMAP degradation, sourdough yeasts including K. exigua modify the nutritional composition of fermented grain products. In studies using specific strains and fermentation conditions, significant improvements were observed in parameters related to glycemic response, satiety, or gastrointestinal comfort after bread ingestion. Sourdough has great potential to produce a variety of functional foods; however, its complex and dynamic ecosystem requires further standardization.
• Endocrine/Metabolic System (Blood Glucose): The acidification of dough and reduction of rapidly digestible starch by sourdough fermentation is associated with a modulated postprandial glycemic response, though clinical results are inconsistent across trials.
• Mineral Absorption / Skeletal Health: Through phytase-mediated degradation of phytic acid, sourdough fermentation involving K. exigua is associated with increased bioavailability of iron, zinc, magnesium, calcium, and other divalent and trivalent ions. Phytic acid's strong negative charge across a wide pH range negatively impacts the bioavailability of divalent and trivalent mineral ions such as Zn²⁺, Mg²⁺, Ca²⁺, Mn²⁺, Cu²⁺, Fe²⁺, and Fe³⁺.
• Immune/Inflammatory System: Sourdough fermentation stimulates proteolysis that alters the composition and activity of wheat proteins including amylase-trypsin inhibitors (ATIs), which have known pro-inflammatory properties.

9. Dosage Forms and Reported Dosages

S. exiguus / K. exigua is not marketed in standardized dosage forms as an isolated dietary supplement, and no pharmacopoeial monograph establishes dosing guidelines for this organism independently. The scientific literature treats it exclusively as a fermentation microorganism rather than as a supplemental product. Therefore, no specific dosages from clinical studies can be reported for this organism in isolation.

In the context of sourdough bread as a food vehicle, a total of 573 articles were retrieved and investigated, of which 25 clinical trials met inclusion criteria, and those 25 trials included a total of 542 individuals. Doses of sourdough bread tested in clinical trials vary widely between studies and are not standardized in a way that can be attributed to K. exigua specifically. The microbial content of baked sourdough bread is largely non-viable following thermal processing at baking temperatures.

In fermentation applications, studies exploring K. exigua in wine production have tested strains in monoculture and multistarter fermentation with S. cerevisiae, but these are fermentation-technology experiments rather than human dosing studies.

10. Safety Considerations

10.1 GRAS Status and History of Safe Use

Kazachstania exigua is classified as GRAS (Generally Recognized As Safe) by virtue of its long history of use in food fermentation. It has been a component of human food — specifically sourdough bread — across many cultures and for thousands of years. The sourdough process is one of the oldest spontaneous biotechnological processes in cereal food production.

10.2 Genetic Heterogeneity Among Named Isolates

A relevant safety-adjacent consideration is the genetic heterogeneity of organisms named S. exiguus. Isolates previously described as S. exiguus showed a high degree of polymorphism; only one (CBS 1514) of ten studied isolates had a sequence identical to the type strain NRRL Y-12640. This means that historical safety data attributed to S. exiguus in the literature may encompass multiple genetically distinct strains, and properties established for one strain cannot necessarily be extrapolated to all.

10.3 Non-Pathogenicity

Recognition of the genus Kazachstania from phenotype alone is difficult because the species assigned have little definitive group-specific morphology and their restricted responses on standard taxonomic tests do not reliably separate them from certain species in other genera. Lack of phenotypic identity is not peculiar to Kazachstania species, but is characteristic of many species in the "Saccharomyces complex." Nonetheless, K. exigua has no established record of pathogenicity in immunocompetent individuals. It is distinct from opportunistic pathogens within the broader fungal kingdom.

10.4 Absence of Standalone Adverse Event Data

There are no published clinical adverse event reports specifically attributable to S. exiguus / K. exigua as an isolated ingredient. Its context of exposure is almost entirely through traditionally fermented foods, in which it is one component of a complex microbial and chemical matrix. No drug-interaction data specific to this organism appear in the peer-reviewed literature.

10.5 Potential Consideration for Immunocompromised Individuals

As a member of the broader Saccharomyces complex, K. exigua shares the general caveat applicable to live yeasts: immunocompromised individuals may face theoretical increased risk from consumption of live fermented foods containing viable yeast cells, consistent with general food-safety principles applicable to probiotic and fermented food use in clinical populations. No adverse events for K. exigua specifically are documented in the retrieved literature.

11. Limitations of the Evidence Base

It is currently difficult to establish a clear consensus with regard to the beneficial effects of sourdough on health compared with other types of bread because a variety of factors, such as the microbial composition of sourdough, fermentation parameters, cereals, and flour types, potentially influence the nutritional properties of bread.

Much of the data presented in dossiers submitted to EFSA for approval of sourdough health claims are based on the study of isolated factors in vitro, ex vivo, and in animals rather than properly powered human clinical trials. No clinical trials have been performed using S. exiguus / K. exigua as an isolated, defined intervention in human subjects. The organism's health relevance is therefore inferential — derived from its role as a fermentation agent in foods whose nutritional properties have been studied in humans — rather than directly demonstrated.

The reviewed data suggest that sourdough has great potential to produce a variety of functional foods; however, its complex and dynamic ecosystem requires further standardization to conclude its clinical health benefits.

References

• UC Davis Viticulture and Enology — Saccharomyces exiguous species profile
• Kurtzman CP (2003). Phylogenetic circumscription of Saccharomyces, Kluyveromyces and other members of the Saccharomycetaceae. FEMS Yeast Research 4(3):233–245
• Biota of New Zealand — Saccharomyces exiguus Reess ex E.C. Hansen 1888 (nomenclatural record)
• GBIF Backbone Taxonomy — Kazachstania exigua species page
• NCBI Taxonomy Browser — Maudiozyma exigua (syn. Kazachstania exigua)
• Casaregola et al. (2003). High-rate evolution of Saccharomyces sensu lato chromosomes. FEMS Yeast Research 3(4):363–379
• Wikipedia — Sourdough (microbiology section)
• ScienceDirect Topics — Sourdough Bread overview
• ScienceDirect Topics — Candida humilis / Kazachstania exigua overview
• De Vuyst L et al. (2016). Yeast diversity of sourdoughs and associated metabolic properties and functionalities. International Journal of Food Microbiology
• Nuobariene L et al. (2012). Isolation and identification of phytase-active yeasts from sourdoughs. LWT – Food Science and Technology
• Nionelli L & Rizzello CG (2019). Isolation and identification of lactic acid bacteria with phytase activity from sourdough. Journal of Food Science and Technology (PMC6848837)
• Dimov I et al. (2023). Nutritional benefits of sourdoughs: A systematic review. Advances in Nutrition (PMC10103004)
• Dimov I et al. (2022). Nutritional benefits of sourdoughs: A systematic review. Advances in Nutrition (ScienceDirect)
• Gänzle MG & Ripari V (2023). Does sourdough bread provide clinically relevant health benefits? Frontiers in Nutrition (PMC10399781)
• Gänzle MG & Ripari V (2023). Does sourdough bread provide clinically relevant health benefits? Frontiers in Nutrition
• Harth H et al. (2020). Interactions between Kazachstania humilis yeast species and lactic acid bacteria in sourdough. PMC7074792
• De Vuyst L et al. (2020). Diverse microbial composition of sourdoughs from different origins. Frontiers in Microbiology
• Pepe O et al. (2021). Physiological performance of Kazachstania unispora in sourdough environments. PMC8060213
• Lau SW et al. (2021). Sourdough microbiome comparison and benefits. PMC8306212
• Abedinzadeh Z et al. (2024). Exploring the nutritional impact of sourdough fermentation: its mechanisms and functional potential. PMC11172170
• Ziegler JU et al. (2018). Use of sourdough in low FODMAP baking. PMC6068548
• Zevallos VF et al. (2020). Sourdough fermentation degrades wheat alpha-amylase/trypsin inhibitor (ATI) and reduces pro-inflammatory activity. PMC7404469
• Sourdough Fermentation and Gluten Reduction: A Biotechnological Approach for Gluten-Related Disorders (ResearchGate)
• Sourdough Fermentation and Gluten Reduction: A Biotechnological Approach for Gluten-Related Disorders. Fermentation 2025, 16(7), 161
• Rizzello CG et al. (2007). Highly efficient gluten degradation by lactobacilli and fungal proteases during food processing: new perspectives for celiac disease. PubMed 17513580
• Vaudano E et al. (2014). Exploring the possibility of using Kazachstania exigua (ex. Saccharomyces exiguus) in wine production. ResearchGate
• Díaz-Montaño DM et al. (2017). Impact of environmental conditions on microbial diversity during mezcal fermentation in Oaxaca. LWT – Food Science and Technology
• Sourdough Bread Quality: Facts and Factors. PMC11241011
• Bourrie BCT et al. (2016). The microbiota and health promoting characteristics of the fermented beverage kefir. PMC4854945
• Gallone B et al. (2020). History and domestication of Saccharomyces cerevisiae in bread baking. Frontiers in Genetics