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Yeasts are eukaryotic, single-celled microorganisms classified as members of the fungus kingdom. The first yeast originated hundreds of millions of years ago, and at least 1,500 species are currently recognized. They are estimated to constitute 1% of all described fungal species.
Lactobacillus is a genus of Gram-positive, aerotolerant anaerobes or microaerophilic, rod-shaped, non-spore-forming bacteria. Until March 2020, the genus Lactobacillus comprised over 260 phylogenetically, ecologically, and metabolically diverse species; a taxonomic revision of the genus in 2020 assigned lactobacilli to 25 genera.
Proteus is a genus of Gram-negative Proteobacteria. Proteus bacilli are widely distributed in nature as saprophytes, being found in decomposing animal matter, sewage, manure soil, the mammalian intestine, and human and animal feces. They are opportunistic pathogens, commonly responsible for urinary and septic infections, often nosocomial.
Malolactic fermentation is a process in winemaking in which tart-tasting malic acid, naturally present in grape must, is converted to softer-tasting lactic acid. Malolactic fermentation is most often performed as a secondary fermentation shortly after the end of the primary fermentation, but can sometimes run concurrently with it. The process is standard for most red wine production and common for some white grape varieties such as Chardonnay, where it can impart a "buttery" flavor from diacetyl, a byproduct of the reaction.
Saccharomyces is a genus of fungi that includes many species of yeasts. Saccharomyces is from Greek σάκχαρον (sugar) and μύκης (fungus) and means sugar fungus. Many members of this genus are considered very important in food production. It is known as the brewer's yeast or baker's yeast. They are unicellular and saprotrophic fungi. One example is Saccharomyces cerevisiae, which is used in making bread, wine, and beer, and for human and animal health. Other members of this genus include the wild yeast Saccharomyces paradoxus that is the closest relative to S. cerevisiae, Saccharomyces bayanus, used in making wine, and Saccharomyces cerevisiaevar boulardii, used in medicine.
Pediococcus is a genus of gram-positive lactic acid bacteria, placed within the family of Lactobacillaceae. They usually occur in pairs or tetrads, and divide along two planes of symmetry, as do the other lactic acid cocci genera Aerococcus and Tetragenococcus. They are purely homofermentative. Pediococcus dextrinicus has recently been reassigned to the genus Lactobacillus.
Lactobacillales are an order of gram-positive, low-GC, acid-tolerant, generally nonsporulating, nonrespiring, either rod-shaped (bacilli) or spherical (cocci) bacteria that share common metabolic and physiological characteristics. These bacteria, usually found in decomposing plants and milk products, produce lactic acid as the major metabolic end product of carbohydrate fermentation, giving them the common name lactic acid bacteria (LAB).
Alcaligenes is a genus of Gram-negative, aerobic, rod-shaped bacteria. The species are motile with amphitrichous flagella and rarely nonmotile. It is a genus of non-fermenting bacteria. Additionally, some strains of Alcaligenes are capable of anaerobic respiration, but they must be in the presence of nitrate or nitrite; otherwise, their metabolism is respiratory and never fermentative; The genus does not use carbohydrates. Strains of Alcaligenes are found mostly in the intestinal tracts of vertebrates, decaying materials, dairy products, water, and soil; they can be isolated from human respiratory and gastrointestinal tracts and wounds in hospitalized patients with compromised immune systems. They are occasionally the cause of opportunistic infections, including nosocomial sepsis.
The Lactobacillaceae are a family of lactic acid bacteria. It is the only family in the Lactic acid bacteria which includes homofermentative and heterofermentative organisms; in the Lactobacillaceae, the pathway used for hexose fermentation is a genus-specific trait. Lactobacillaceae include the homofermentative lactobacilli Lactobacillus, Holzapfelia, Amylolactobacillus, Bombilactobacillus, Companilactobacillus, Lapidilactobacillus, Agrilactobacillus, Schleiferilactobacillus, Loigolactobacillus, Lacticaseibacillus, Latilactobacillus, Dellaglioa, Liquorilactobacillus, Ligilactobacillus and Lactiplantibacillus, the heterofermentative lactobacilli Furfurilactobacillus, Paucilactobacillus, Limosilactobacillus, Fructilactobacillus, Acetilactobacillus, Apilactobacillus, Levilactobacillus, Secundilactobacillus and Lentilactobacillus, which were previously classified in the genus Lactobacillus and the heterofermentative genera Convivina, Frucctobacillus, Leuconosto, Oenococcus and Weissella which were previously classified in the Leuconostocaceae.
Dadiah (Minangkabau) or dadih (Indonesian) a traditional fermented milk popular among people of West Sumatra, Indonesia, is made by pouring fresh, raw, unheated, buffalo milk into a bamboo tube capped with a banana leaf and allowing it to ferment spontaneously at room temperature for two days.
Food microbiology is the study of the microorganisms that inhibit, create, or contaminate food. This includes the study of microorganisms causing food spoilage; pathogens that may cause disease ; microbes used to produce fermented foods such as cheese, yogurt, bread, beer, and wine; and microbes with other useful roles, such as producing probiotics.
Pediococcus acidilactici is a species of Gram-positive cocci that is often found in pairs or tetrads. P. acidilactici is a homofermentative bacterium that can grow in a wide range of pH, temperature, and osmotic pressure, therefore being able to colonize the digestive tract. It has emerged as a potential probiotic that has shown promising results in animal and human experiments, though some of the results are limited. They are commonly found in fermented vegetables, fermented dairy products, and meat.
Sour beer is beer which has an intentionally acidic, tart, or sour taste. Traditional sour beer styles include Belgian lambics, gueuze and Flanders red ale, and German gose.
Aspergillus sojae is a species of fungus in the genus Aspergillus.
Pediococcus damnosus is a species of Gram-positive bacteria. The genus Pediococcus is a spherical cocci shaped bacteria with nonmotile, non spore-forming and homofermentative properties. P. damnosus is a chemo-organotrophic, catalase negative, facultative anaerobe. Strains of this species frequently grow in wine and beer, where they overproduce glucan and spoil products by increasing their viscosity. P. damnosus is a lactic acid bacteria (LAB), that can tolerate the low pH and higher ethanol levels that are found in beer. The ability to grow in beer is a strain specific characteristic of the species P. damnosus. Pediococcus damnosus LMG 28219 is a lactic acid bacterium that has proved to be capable of growing in beer.
The role of yeast in winemaking is the most important element that distinguishes wine from grape juice. In the absence of oxygen, yeast converts the sugars of wine grapes into alcohol and carbon dioxide through the process of fermentation. The more sugars in the grapes, the higher the potential alcohol level of the wine if the yeast are allowed to carry out fermentation to dryness. Sometimes winemakers will stop fermentation early in order to leave some residual sugars and sweetness in the wine such as with dessert wines. This can be achieved by dropping fermentation temperatures to the point where the yeast are inactive, sterile filtering the wine to remove the yeast or fortification with brandy or neutral spirits to kill off the yeast cells. If fermentation is unintentionally stopped, such as when the yeasts become exhausted of available nutrients and the wine has not yet reached dryness, this is considered a stuck fermentation.
Lactobacillus fabifermentans is a member of the genus Lactobacillus, the most diverse genus among lactic acid bacteria (LAB), a group of Gram-positive bacteria that produce lactic acid as their major fermented end product and that are often involved in food fermentation. L. fabifermentans was proposed in 2009 as a new species, after the type strain LMG 24284T has been isolated from Ghanaian cocoa fermentation. Analysis of the 16S rRNA gene sequence demonstrated that this species is a member of the Lactobacillus plantarum species group but further analysis demonstrated that it is possible to differentiate it from the nearest neighbors by means of DNA-DNA hybridization experiments, pheS sequence analysis, whole-cell protein electrophoresis, fluorescent amplified fragment length polymorphism analysis and biochemical characterization.
Bifidobacterium asteroides is a gram-positive, rod-shaped species of bacteria. Various strains of this species have been isolated from the hindguts of honey bees. Prior to 1969, this species was referred to as strains of Bacillus constellatus.
Pediococcus claussenii is a species of Gram-positive bacteria. Like other Pediococcus species, P. claussenii is implicated in the spoilage of fermented beverages due to its production of diacetyl. Strains of this species were originally isolated from spoiled beer.
Tetragenococcus is a gram-positive, facultatively aerobic, moderately halophilic and nonmotile bacterial genus from the family of Enterococcaceae.
References
- ↑ Zhang, B.; Tong, H.; Dong, X. (1 September 2005). "Pediococcus cellicola sp. nov., a novel lactic acid coccus isolated from a distilled-spirit-fermenting cellar". International Journal of Systematic and Evolutionary Microbiology. 55 (5): 2167–2170. doi: 10.1099/ijs.0.63778-0 . PMID 16166726.
