Yeasts refer to the fungi of the department of what? Yeast: structure, species

The fact that yeasts are fungi is probably known to many. And what about the further classification of the representatives of the kingdom? It is known that yeast belongs to the fungi of the Ascomycetes and Basidiomycetes. What does this mean? Let's try to figure it out together.

Yeast - mushrooms

And the fungi are unicellular. They lost mycelium as a result of evolutionary processes, as they believe, in connection with the transition to habitation in liquid substrates that are rich in organic matter and very favorable for the life activity of these organisms. Total yeast is up to 1,500 species. All yeasts are unicellular mushrooms.

Dimensions

Single isolated cells of these fungi reach up to 7 μm in diameter, but some grow to 40 μm. However, some yeast-like ones still form a mycelium at the stages of their life cycle , and in some cases also a fruiting body. At present, for example, baker's yeast are the first eukaryotes whose genome has been identified and deciphered.

A bit of history

Yeasts are mushrooms, "domesticated" by man, and already long ago. They have long been used for millennia for culinary purposes: baking, creating conditions for fermentation. Already in ancient Egypt, there were bakeries and, obviously, the use of yeast. And in some countries in the extreme antiquity, along with baking fresh (for example, matzah or lavash), the production of yeast bread has also gained popularity. Brewer's yeast was known to the Egyptians already more than six thousand years ago, and with the help of these organisms people cooked this foamy drink.

Interestingly, for the new leaven in many farms from olden times used the remains of the old. So, according to scientists, there was a selection of yeast, there were species that do not occur in the wild. And many consider some species of yeast as a product exclusively of human activities (for example, cultivars: wheat, rye and others).

Zymology

This is the name of science that describes and studies the life and activity of these organisms. Yeasts refer to fungi, their pure culture was first isolated in 1881 in Denmark, and in 1883 it was already used for beer production. At the end of the 19th century a classification of yeast was created, and in the 20th century collections and determinants of known cultures appeared. Yeast refers to the fungi of the Ascomycete department until the middle of the last century. Scientists observed their sexual cycle, generalizing as a taxonomic group (marsupial mushrooms). But in Japan, one of the scientists induced reproduction and yeast-basidiomycetes. Thus, experts came to the conclusion that yeast fungi (photo below) were formed during the evolution independently of these two divisions of the kingdom (ascomycetes and basidiomycetes). The data has also been confirmed by molecular biological studies of organisms. They are not a taxon, but, most likely, a special life form.

Ascomycetes and Basidiomycetes

So, yeast refers to the fungi of the Ascomycete and Basidiomycetes (more precisely, to two different departments). All of them are a sub-kingdom of higher mushrooms. You can distinguish them according to the characteristics of life cycles and some other signs: param pairs in DNA, the presence of urease. Ascomycetes, or marsupials - a fairly extensive department, which includes up to thirty thousand species (by the way, all known truffles belong to this department, as well as morels and stitches). Among all - and yeast, which are considered scientists once again unicellular organisms.

Habitat

Usually these organisms live in places that are rich in sugars - substrates on the surface of fruits and berries, leaves. They can eat the products of plant life: nectar, secretions, wound juices. Do not disdain and dead phytomass. They can also live in soil litter from organic matter, and in natural water masses. Some yeasts are present in the intestines of insects that feed on wood. A lot of yeast and on the leaves that are affected by aphids.

Application

Some types of yeast cultures have long been in demand in cooking, making bakery and forcing alcohol. Kvass, bread, beer, wine can not do without these small helpers. All these yeasts, known to mankind for a long time, belong to the fungi of the Ascomycete department. For the production of strong alcohol they are involved in distillation at the fermentation stage. Nowadays some yeast cultures are used in a wide range of biotechnologies: the production of fuel and food additives and enzymes. And in science they are used as experimental cultures for the research of geneticists.

Saccharomyces cerevisiae

• Baking uses the culture of Saccharomyces cerevisiae, known as baker's yeast. They produce alcoholic fermentation , which enhances the taste and aroma of the bread product (alcohol after, during the baking, evaporates). In addition, carbon dioxide, which forms in the mass, causes the dough to rise, giving the test porosity and softness.
• In nature, yeast cultures develop naturally on grape berries, which can be seen as whitish plaque. But the true wine yeast is considered to be Saccharomyces cerevisiae, which are rare on clusters. It is this variety that is used for the most part for making wine material. As a result of yeast processing of sugars contained in grape juice, ethanol is produced, and yeast with increasing degree degenerates. And to produce champagne, the finished wine is fermented repeatedly, adding a yeast culture.
• In brewing, a sprouted grain of barley (malt) and yeast of lower and higher fermentation are used. Malt is grinded, boiled, mixed with water and fermented, using Saccharomyces cerevisiae or some other yeast. Kvass is produced in approximately the same way, but in addition to yeast, lactobacilli are also used.
• The aforementioned yeasts, widely used in the national economy, belong to the detachment of Ascomycete mushrooms. And still popular for the preparation of drinks are yeast and bacteria associations: for example, a tea fungus or a Tibetan mushroom. They have many useful properties for the human body, and regular use of these drinks prevents all kinds of diseases of the gastrointestinal tract and other internal organs.