''Zygosaccharomyces rouxii'' is a species of yeast in the genus Zygosaccharomyces. Initially described as ''Saccharomyces rouxii'' by Boutroux in 1883, it was then moved to the genus ''Zygosaccharomyces'' in the work of Barnett ''et al''. It is remarkably tolerant of high concentrations of sugar or salt, making it a spoilage agent of otherwise stable foods, but also present in fermentation of products such as

soy sauce Soy sauce (sometimes called soya sauce in British English) is a liquid condiment of China, Chinese origin, traditionally made from a fermentation (food), fermented paste of soybeans, roasted cereal, grain, brine, and ''Aspergillus oryzae'' or ''A ...

balsamic vinegar Balsamic vinegar () is a dark, concentrated, intensely flavoured vinegar made wholly or partially from Must, grape must: freshly crushed grape juice with all the skins, seeds, and stems. Etymology The Italian language, Italian word (from Lat ...

Description

It is a

diploid Ploidy () is the number of complete sets of chromosomes in a cell, and hence the number of possible alleles for autosomal and pseudoautosomal genes. Here ''sets of chromosomes'' refers to the number of maternal and paternal chromosome copies, ...

, homothallic, and osmophilic (capable of withstanding high osmotic pressures, such as high concentrations of sugar) yeast. It produces ethanol by alcoholic fermentation. It is found on grapes, in urine, fermented foods, syrups (maple), honey, grape juice concentrate, marzipan, candied fruit, miso,

marmalade Marmalade (from the Portuguese ''marmelada'') is a fruit preserves, fruit preserve made from the juice and peel of citrus fruits boiled with sugar and water. The well-known version is made from bitter orange. It also has been made from lemons ...

, and wine. It is capable of fermenting

dextrose Glucose is a sugar with the molecular formula , which is often abbreviated as Glc. It is overall the most abundant monosaccharide, a subcategory of carbohydrates. It is mainly made by plants and most algae during photosynthesis from water an ...

(D-glucose) and

maltose } Maltose ( or ), also known as maltobiose or malt sugar, is a disaccharide formed from two units of glucose joined with an α(1→4) bond. In the isomer isomaltose, the two glucose molecules are joined with an α(1→6) bond. Maltose is the tw ...

but has no fermentation activity on

sucrose Sucrose, a disaccharide, is a sugar composed of glucose and fructose subunits. It is produced naturally in plants and is the main constituent of white sugar. It has the molecular formula . For human consumption, sucrose is extracted and refined ...

and

lactose Lactose is a disaccharide composed of galactose and glucose and has the molecular formula C12H22O11. Lactose makes up around 2–8% of milk (by mass). The name comes from (Genitive case, gen. ), the Latin word for milk, plus the suffix ''-o ...

. Cells are small, round or oval and linked together in chains. It is particularly tolerant of a wide range of acidity and sugar and salt concentration but is sensitive to temperatures above 35°C unless protected by a small amount of sugar in the medium. In lab, is grown on malt extract agar. After 3 days at 25°C, cells are spheroidal to cylindrical, either singly or in pairs or sometimes in small clumps.

History

Two collaborators of

Louis Pasteur Louis Pasteur (, ; 27 December 1822 – 28 September 1895) was a French chemist, pharmacist, and microbiologist renowned for his discoveries of the principles of vaccination, Fermentation, microbial fermentation, and pasteurization, the la ...

are the origin of the discovery of this new yeast: it was isolated by Émile Roux from fermenting fruit juice and was described as ''Saccharomyces rouxi'' by Léon Boutroux in 1883. It has been described multiple times under different names. See the Catalogue of Lif
checklist
It has been genetically sequenced in 2009.

Usage

In food, this yeast is used in the fermentation of soybeans during the manufacture of

and miso where it plays an important role in the development of aromas. It is also present in the fermentation of traditional Italian

.''Zygosaccharomyces rouxii'' together with '' Zygosaccharomyces bailii, Z. pseudorouxii, Z. mellis, Z. bisporus, Z. lentus,

Hanseniaspora valbyensis ''Hanseniaspora'' is a genus of yeasts. The name ''Kloeckera'' is applied to its anamorph form. They are typically apiculate (lemon-shaped) in shape and often found in grape musts pre-fermentation. The genus name ''Hanseniaspora'' honours Emil ...

, Hanseniaspora osmophila, Candida lactis-condensi, Candida stellata, Saccharomycodes ludwigii,

Saccharomyces cerevisiae ''Saccharomyces cerevisiae'' () (brewer's yeast or baker's yeast) is a species of yeast (single-celled fungal microorganisms). The species has been instrumental in winemaking, baking, and brewing since ancient times. It is believed to have be ...

'' In the manufacture of soy sauce, soybeans and grain are inoculated with mold cultures such as '' Aspergillus oryzae'' to make what is called koji, then it is put in brine and seeded with the lactic acid bacteria '' Tetragenococcus halophilus'' (=''Pediococcus halophilus'') which produces lactic acid then with ''Zygosaccharomyces rouxii'' which ferments alcohol. Miso is obtained from a cereal koji seeded with a mold (''Aspergillus oryzae'') which is then salted and fermented by lactic acid bacteria. (''Enterococcus'', ''Pediococcus''...) and yeasts like ''Z. rouxii''. ''Z. rouxii'' produces alcoholic fermentation and hydrolyzes various amino acids into their respective alcohols. It synthesises aromatic components HEMF and HDMF.4-hydroxy-2(or5)ethyl-5(or2)-methyl-3(2H)-furanone (HEMF) and 4-hydroxy-2,5dimethyl-3(2H)-furanone (HDMF) ''Z. rouxii'' can cause spoilage of certain high-sugar and high-salt foods such as condensed milk, fruit juices, jam, pastries and salad dressings. It causes alcoholic fermentation: the alteration of the product is manifested by an alcoholic taste and especially by an intense gas release which makes the drink fizzy and which can cause the packaging to swell.

Notes

References

External links

* {{Taxonbar, from=Q10725467 Osmophiles Saccharomycetaceae Yeasts Fungi described in 1883 Fungus species