93-433: See text Septoria are ascomycete pycnidia -producing fungi that cause numerous leaf spot diseases on field crops , forages and many vegetables including tomatoes which are known to contract Septoria musiva from nearby cottonwood trees , and is responsible for yield losses. The genus is widespread, and estimated to contain 1072 species. Pycnidia produce needle-like pycnidiospores . Septoria apiicola
186-1196: A thallus usually referred to as the mycelium , which—when visible to the naked eye (macroscopic)—is commonly called mold . During sexual reproduction, many Ascomycota typically produce large numbers of asci . The ascus is often contained in a multicellular, occasionally readily visible fruiting structure, the ascocarp (also called an ascoma ). Ascocarps come in a very large variety of shapes: cup-shaped, club-shaped, potato-like, spongy, seed-like, oozing and pimple-like, coral-like, nit-like, golf-ball-shaped, perforated tennis ball-like, cushion-shaped, plated and feathered in miniature ( Laboulbeniales ), microscopic classic Greek shield-shaped, stalked or sessile. They can appear solitary or clustered. Their texture can likewise be very variable, including fleshy, like charcoal (carbonaceous), leathery, rubbery, gelatinous, slimy, powdery, or cob-web-like. Ascocarps come in multiple colors such as red, orange, yellow, brown, black, or, more rarely, green or blue. Some ascomyceous fungi, such as Saccharomyces cerevisiae , grow as single-celled yeasts, which—during sexual reproduction—develop into an ascus, and do not form fruiting bodies. In lichenized species,
279-472: A bottle shaped cell called a phialide , from which the spores are produced. Not all of these asexual structures are a single hypha. In some groups, the conidiophores (the structures that bear the conidia) are aggregated to form a thick structure. E.g. In the order Moniliales, all of them are single hyphae with the exception of the aggregations, termed as coremia or synnema. These produce structures rather like corn-stokes, with many conidia being produced in
372-506: A double-dividing wall with a central lamella (layer) forms between the cells; the central layer then breaks down thereby releasing the spores. In rhexolytic dehiscence, the cell wall that joins the spores on the outside degenerates and releases the conidia. Several Ascomycota species are not known to have a sexual cycle. Such asexual species may be able to undergo genetic recombination between individuals by processes involving heterokaryosis and parasexual events. Parasexuality refers to
465-433: A form of pneumonia . Asci of Ascosphaera fill honey bee larvae and pupae causing mummification with a chalk-like appearance, hence the name "chalkbrood". Yeasts for small colonies in vitro and in vivo , and excessive growth of Candida species in the mouth or vagina causes "thrush", a form of candidiasis . The cell walls of the ascomycetes almost always contain chitin and β-glucans , and divisions within
558-476: A further mitotic division that results in eight nuclei in each ascus. The nuclei along with some cytoplasma become enclosed within membranes and a cell wall to give rise to ascospores that are aligned inside the ascus like peas in a pod. Upon opening of the ascus, ascospores may be dispersed by the wind, while in some cases the spores are forcibly ejected form the ascus; certain species have evolved spore cannons, which can eject ascospores up to 30 cm. away. When
651-737: A hypha. Vegetative hyphae of most ascomycetes contain only one nucleus per cell ( uninucleate hyphae), but multinucleate cells—especially in the apical regions of growing hyphae—can also be present. In common with other fungal phyla, the Ascomycota are heterotrophic organisms that require organic compounds as energy sources. These are obtained by feeding on a variety of organic substrates including dead matter, foodstuffs, or as symbionts in or on other living organisms. To obtain these nutrients from their surroundings, ascomycetous fungi secrete powerful digestive enzymes that break down organic substances into smaller molecules, which are then taken up into
744-400: A large scale in the 1980s and 1990s as a fuel additive to gasoline, due to government regulations. Today, ethanol continues to be explored as a sustainable and renewable fuel source, with researchers developing new technologies and biomass sources for its production. Homolactic fermentation (producing only lactic acid) is the simplest type of fermentation. Pyruvate from glycolysis undergoes
837-529: A large-scale specialized structure that helps to spread them. These two basic types can be further classified as follows: Sometimes the conidia are produced in structures visible to the naked eye, which help to distribute the spores. These structures are called "conidiomata" (singular: conidioma ), and may take the form of pycnidia (which are flask-shaped and arise in the fungal tissue) or acervuli (which are cushion-shaped and arise in host tissue). Dehiscence happens in two ways. In schizolytic dehiscence,
930-433: A mass from the aggregated conidiophores. The diverse conidia and conidiophores sometimes develop in asexual sporocarps with different characteristics (e.g. acervulus, pycnidium, sporodochium). Some species of ascomycetes form their structures within plant tissue, either as parasite or saprophytes. These fungi have evolved more complex asexual sporing structures, probably influenced by the cultural conditions of plant tissue as
1023-431: A microscopic sexual structure in which nonmotile spores , called ascospores , are formed. However, some species of Ascomycota are asexual and thus do not form asci or ascospores. Familiar examples of sac fungi include morels , truffles , brewers' and bakers' yeast , dead man's fingers , and cup fungi . The fungal symbionts in the majority of lichens (loosely termed "ascolichens") such as Cladonia belong to
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#17328919027991116-662: A process formerly thought to be merely a chemical change. His work in identifying the role of microorganisms in food spoilage led to the process of pasteurization . In 1877, working to improve the French brewing industry , Pasteur published his famous paper on fermentation, " Etudes sur la Bière ", which was translated into English in 1879 as "Studies on fermentation". He defined fermentation (incorrectly) as "Life without air", yet he correctly showed how specific types of microorganisms cause specific types of fermentations and specific end-products. Although showing fermentation resulted from
1209-585: A redox cofactor , which in turn transfers them to an organic compound. ATP is generated in the process, and it can be formed by substrate-level phosphorylation or by ATP synthase. When glucose is fermented, it enters glycolysis or the pentose phosphate pathway and is converted to pyruvate. From pyruvate, pathways branch out to form a number of end products (e.g. lactate). At several points, electrons are released and accepted by redox cofactors ( NAD and ferredoxin ). At later points, these cofactors donate electrons to their final acceptor and become oxidized. ATP
1302-469: A religious significance in Judaism and Christianity . The Baltic god Rugutis was worshiped as the agent of fermentation. In alchemy , fermentation ("putrefaction") was symbolized by Capricorn [REDACTED] ♑︎ . In 1837, Charles Cagniard de la Tour , Theodor Schwann and Friedrich Traugott Kützing independently published papers concluding, as a result of microscopic investigations, that yeast
1395-545: A separate artificial phylum , the Deuteromycota (or "Fungi Imperfecti"). Where recent molecular analyses have identified close relationships with ascus-bearing taxa, anamorphic species have been grouped into the Ascomycota, despite the absence of the defining ascus. Sexual and asexual isolates of the same species commonly carry different binomial species names, as, for example, Aspergillus nidulans and Emericella nidulans , for asexual and sexual isolates, respectively, of
1488-530: A simple redox reaction, forming lactic acid . Overall, one molecule of glucose (or any six-carbon sugar) is converted to two molecules of lactic acid: It occurs in the muscles of animals when they need energy faster than the blood can supply oxygen. It also occurs in some kinds of bacteria (such as lactobacilli ) and some fungi . It is the type of bacteria that convert lactose into lactic acid in yogurt , giving it its sour taste. These lactic acid bacteria can carry out either homolactic fermentation , where
1581-532: A stationary phase after most of the nutrients have been consumed, and then the cells die. Fed-batch fermentation is a variation of batch fermentation where some of the ingredients are added during the fermentation. This allows greater control over the stages of the process. In particular, production of secondary metabolites can be increased by adding a limited quantity of nutrients during the non-exponential growth phase. Fed-batch operations are often sandwiched between batch operations. The high cost of sterilizing
1674-850: A steady state and avoid contamination, and the design tends to be complex. Typically the fermentor must run for over 500 hours to be more economical than batch processors. The use of fermentation, particularly for beverages , has existed since the Neolithic and has been documented dating from 7000 to 6600 BCE in Jiahu , China , 5000 BCE in India , Ayurveda mentions many Medicated Wines, 6000 BCE in Georgia, 3150 BCE in ancient Egypt , 3000 BCE in Babylon , 2000 BCE in pre-Hispanic Mexico, and 1500 BC in Sudan . Fermented foods have
1767-408: A substrate. These structures are called the sporodochium . This is a cushion of conidiophores created from a pseudoparenchymatous stroma in plant tissue. The pycnidium is a globose to flask-shaped parenchymatous structure, lined on its inner wall with conidiophores. The acervulus is a flat saucer shaped bed of conidiophores produced under a plant cuticle, which eventually erupt through
1860-580: A sugar solution, forming carbon dioxide and alcohol much like living yeasts. Buechner's results are considered to mark the birth of biochemistry. The "unorganized ferments" behaved just like the organized ones. From that time on, the term enzyme came to be applied to all ferments. It was then understood fermentation is caused by enzymes produced by microorganisms. In 1907, Buechner won the Nobel Prize in chemistry for his work. Advances in microbiology and fermentation technology have continued steadily up until
1953-594: A temperature of 70 °C. This is just below its boiling point (78 °C), making it easy to extract. Halophilic bacteria can produce bioplastics in hypersaline conditions. Solid-state fermentation adds a small amount of water to a solid substrate; it is widely used in the food industry to produce flavors, enzymes and organic acids. In continuous fermentation, substrates are added and final products removed continuously. There are three varieties: chemostats , which hold nutrient levels constant; turbidostats , which keep cell mass constant; and plug flow reactors in which
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#17328919027992046-551: A tetraploid nucleus which divided into four diploid nuclei by meiosis and then into eight haploid nuclei by a supposed process called brachymeiosis , but this hypothesis was disproven in the 1950s. From the fertilized ascogonium, dinucleate hyphae emerge in which each cell contains two nuclei. These hyphae are called ascogenous or fertile hyphae. They are supported by the vegetative mycelium containing uni– (or mono–) nucleate hyphae, which are sterile. The mycelium containing both sterile and fertile hyphae may grow into fruiting body,
2139-423: A variety of stresses such as nutrient limitation. The sexual part of the life cycle commences when two hyphal structures mate . In the case of homothallic species, mating is enabled between hyphae of the same fungal clone , whereas in heterothallic species, the two hyphae must originate from fungal clones that differ genetically, i.e., those that are of a different mating type . Mating types are typical of
2232-798: A vat instead of meat. Industrial fermentation can be used for enzyme production, where proteins with catalytic activity are produced and secreted by microorganisms. The development of fermentation processes, microbial strain engineering and recombinant gene technologies has enabled the commercialization of a wide range of enzymes. Enzymes are used in all kinds of industrial segments, such as food (lactose removal, cheese flavor), beverage (juice treatment), baking (bread softness, dough conditioning), animal feed, detergents (protein, starch and lipid stain removal), textile, personal care and pulp and paper industries. Most industrial fermentation uses batch or fed-batch procedures, although continuous fermentation can be more economical if various challenges, particularly
2325-418: A wide range of consumer goods, from food and drink to industrial chemicals and pharmaceuticals. Since its early beginnings in ancient civilizations, the use of fermentation has continued to evolve and expand, with new techniques and technologies driving advances in product quality, yield, and efficiency. The period from the 1930s onward saw a number of significant advancements in fermentation technology, including
2418-439: A wide range of uses. The definition of fermentation has evolved over the years. The most modern definition is catabolism where organic compounds are both the electron donor and acceptor. A common electron donor is glucose , and pyruvate is a common electron acceptor. This definition distinguishes fermentation from aerobic respiration , where oxygen is the acceptor, and types of anaerobic respiration where inorganic compound
2511-417: Is a dictyospore . In staurospores ray-like arms radiate from a central body; in others ( helicospores ) the entire spore is wound up in a spiral like a spring. Very long worm-like spores with a length-to-diameter ratio of more than 15:1, are called scolecospores . Important characteristics of the anamorphs of the Ascomycota are conidiogenesis , which includes spore formation and dehiscence (separation from
2604-525: Is a stub . You can help Misplaced Pages by expanding it . Ascomycete Ascomycota is a phylum of the kingdom Fungi that, together with the Basidiomycota , forms the subkingdom Dikarya . Its members are commonly known as the sac fungi or ascomycetes . It is the largest phylum of Fungi, with over 64,000 species . The defining feature of this fungal group is the " ascus " (from Ancient Greek ἀσκός ( askós ) 'sac, wineskin'),
2697-439: Is a substrate for methanogens and sulfate reducers , which keep the concentration of hydrogen low and favor the production of such an energy-rich compound, but hydrogen gas at a fairly high concentration can nevertheless be formed, as in flatus . For example, Clostridium pasteurianum ferments glucose to butyrate , acetate , carbon dioxide, and hydrogen gas: The reaction leading to acetate is: Glyoxylate fermentation
2790-400: Is a living organism that reproduces by budding . Schwann boiled grape juice to kill the yeast and found that no fermentation would occur until new yeast was added. However, a lot of chemists, including Antoine Lavoisier , continued to view fermentation as a simple chemical reaction and rejected the notion that living organisms could be involved. This was seen as a reversion to vitalism and
2883-484: Is a tube-shaped vessel, a meiosporangium , which contains the sexual spores produced by meiosis and which are called ascospores . Apart from a few exceptions, such as Candida albicans , most ascomycetes are haploid , i.e., they contain one set of chromosomes per nucleus. During sexual reproduction there is a diploid phase, which commonly is very short, and meiosis restores the haploid state. The sexual cycle of one well-studied representative species of Ascomycota
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2976-465: Is a type of fermentation used by microbes that are able to utilize glyoxylate as a nitrogen source. Other types of fermentation include mixed acid fermentation , butanediol fermentation , butyrate fermentation , caproate fermentation , and acetone–butanol–ethanol fermentation . In food and industrial contexts, any chemical modification performed by a living being in a controlled container can be termed "fermentation". The following do not fall into
3069-458: Is also formed at several points in the pathway. While fermentation is simple in overview, its details are more complex. Across organisms, fermentation of glucose involves over 120 different biochemical reactions. Further, multiple pathways can be responsible for forming the same product. For forming acetate from its immediate precursor (pyruvate or acetyl-CoA), six separate pathways have been found. In ethanol fermentation, one glucose molecule
3162-501: Is converted into two ethanol molecules and two carbon dioxide (CO 2 ) molecules. It is used to make bread dough rise: the carbon dioxide forms bubbles, expanding the dough into a foam. The ethanol is the intoxicating agent in alcoholic beverages such as wine, beer and liquor. Fermentation of feedstocks, including sugarcane , maize , and sugar beets , produces ethanol that is added to gasoline . In some species of fish, including goldfish and carp , it provides energy when oxygen
3255-451: Is described in greater detail in Neurospora crassa . Also, the adaptive basis for the maintenance of sexual reproduction in the Ascomycota fungi was reviewed by Wallen and Perlin. They concluded that the most plausible reason for the maintenance of this capability is the benefit of repairing DNA damage by using recombination that occurs during meiosis . DNA damage can be caused by
3348-436: Is important in several areas of human society. Humans have used fermentation in production of food for 13,000 years. Humans and their livestock have microbes in the gut that carry out fermentation, releasing products used by the host for energy. Fermentation is used at an industrial level to produce commodity chemicals, such as ethanol and lactate. In total, fermentation forms more than 50 metabolic end products with
3441-403: Is in a sense intermediate between lactic acid fermentation and other types, e.g. alcoholic fermentation . Reasons to go further and convert lactic acid into something else include: Hydrogen gas is produced in many types of fermentation as a way to regenerate NAD from NADH. Electrons are transferred to ferredoxin , which in turn is oxidized by hydrogenase , producing H 2 . Hydrogen gas
3534-461: Is known to survive without oxygen. Fermentation uses a range of substrates and forms a variety of metabolic end products. Of the 55 end products formed, the most common are acetate and lactate. Of the 46 chemically-defined substrates that have been reported, the most common are glucose and other sugars. When an organic compound is fermented, it is broken down to a simpler molecule and releases electrons. The electrons are transferred to
3627-498: Is most common in the phylum Bacillota , and it is least common in Actinomycetota . Their most common habitat is host-associated ones, such as the gut. Animals, including humans, also carry out fermentation. The product of fermentation in humans is lactate, and it is formed during anaerobic exercise or in cancerous cells . No animal is known to survive on fermentation alone, even as one parasitic animal ( Henneguya zschokkei )
3720-489: Is often addition of small quantities of chemicals to control the pH or suppress foaming. Batch fermentation goes through a series of phases. There is a lag phase in which cells adjust to their environment; then a phase in which exponential growth occurs. Once many of the nutrients have been consumed, the growth slows and becomes non-exponential, but production of secondary metabolites (including commercially important antibiotics and enzymes) accelerates. This continues through
3813-522: Is only found on Nothofagus (Southern Beech) in the Southern Hemisphere . Asexual reproduction is the dominant form of propagation in the Ascomycota, and is responsible for the rapid spread of these fungi into new areas. It occurs through vegetative reproductive spores, the conidia . The conidiospores commonly contain one nucleus and are products of mitotic cell divisions and thus are sometimes called mitospores, which are genetically identical to
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3906-491: Is reduced into ethanol using the energy and hydrogen from NADH, and the NADH is oxidized into NAD so that the cycle may repeat. The reaction is catalyzed by the enzymes pyruvate decarboxylase and alcohol dehydrogenase. The history of ethanol as a fuel spans several centuries and is marked by a series of significant milestones. Samuel Morey , an American inventor, was the first to produce ethanol by fermenting corn in 1826. However, it
3999-426: Is scarce (along with lactic acid fermentation). Before fermentation, a glucose molecule breaks down into two pyruvate molecules ( glycolysis ). The energy from this exothermic reaction is used to bind inorganic phosphates to ADP, which converts it to ATP, and convert NAD to NADH. The pyruvates break down into two acetaldehyde molecules and give off two carbon dioxide molecules as waste products. The acetaldehyde
4092-621: Is the acceptor. Fermentation had been defined differently in the past. In 1876, Louis Pasteur defined it as "la vie sans air" (life without air). This definition came before the discovery of anaerobic respiration. Later, it had been defined as catabolism that forms ATP through only substrate-level phosphorylation . However, several pathways of fermentation have been discovered to form ATP through an electron transport chain and ATP synthase , also. Some sources define fermentation loosely as any large-scale biological manufacturing process. See Industrial fermentation . This definition focuses on
4185-449: Is the cause of late blight of celery . It is characterized by the production of conidia within pycnidia . The symptoms include chlorotic spots that turn brown and necrotic. Septoria apiicola can survive on seeds. Several species of passion flower are infected by several species of Septoria , and a fungus, which has been going by the name Septoria passiflorae but which is probably an undescribed species, has been used to control
4278-463: Is usually inconspicuous because it is commonly embedded in the substrate, such as soil, or grows on or inside a living host, and only the ascoma may be seen when fruiting. Pigmentation , such as melanin in hyphal walls, along with prolific growth on surfaces can result in visible mold colonies; examples include Cladosporium species, which form black spots on bathroom caulking and other moist areas. Many ascomycetes cause food spoilage, and, therefore,
4371-416: The ascocarp , which may contain millions of fertile hyphae. An ascocarp is the fruiting body of the sexual phase in Ascomycota. There are five morphologically different types of ascocarp, namely: The sexual structures are formed in the fruiting layer of the ascocarp, the hymenium . At one end of ascogenous hyphae, characteristic U-shaped hooks develop, which curve back opposite to the growth direction of
4464-402: The ascogonium , and merges with a gametangium (the antheridium ) of the other fungal isolate. The nuclei in the antheridium then migrate into the ascogonium, and plasmogamy —the mixing of the cytoplasm —occurs. Unlike in animals and plants, plasmogamy is not immediately followed by the merging of the nuclei (called karyogamy ). Instead, the nuclei from the two hyphae form pairs, initiating
4557-452: The conidia . The asexual, non-motile haploid spores of a fungus, which are named after the Greek word for dust (conia), are hence also known as conidiospores . The conidiospores commonly contain one nucleus and are products of mitotic cell divisions and thus are sometimes called mitospores , which are genetically identical to the mycelium from which they originate. They are typically formed at
4650-627: The detritivores (animals that feed on decomposing material) to obtain their nutrients. Ascomycetes, along with other fungi, can break down large molecules such as cellulose or lignin , and thus have important roles in nutrient cycling such as the carbon cycle . The fruiting bodies of the Ascomycota provide food for many animals ranging from insects and slugs and snails ( Gastropoda ) to rodents and larger mammals such as deer and wild boars . Many ascomycetes also form symbiotic relationships with other organisms, including plants and animals. Probably since early in their evolutionary history,
4743-401: The dikaryophase of the sexual cycle, during which time the pairs of nuclei synchronously divide. Fusion of the paired nuclei leads to mixing of the genetic material and recombination and is followed by meiosis . A similar sexual cycle is present in the red algae (Rhodophyta). A discarded hypothesis held that a second karyogamy event occurred in the ascogonium prior to ascogeny, resulting in
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#17328919027994836-685: The ergot fungi, black knot , and the powdery mildews . The members of the genus Cordyceps are entomopathogenic fungi , meaning that they parasitise and kill insects. Other entomopathogenic ascomycetes have been used successfully in biological pest control , such as Beauveria . Several species of ascomycetes are biological model organisms in laboratory research. Most famously, Neurospora crassa , several species of yeasts , and Aspergillus species are used in many genetics and cell biology studies. Ascomycetes are 'spore shooters'. They are fungi which produce microscopic spores inside special, elongated cells or sacs, known as 'asci', which give
4929-650: The invasive Passiflora tarminiana in Hawai'i. In 2013, two large volumes (about 80 pages a piece) on Septoria and septoria-like fungi were published in the open access journal Studies in Mycology . In these papers by Quaedvlieg et al. and Verkley et al., the genus Septoria is clearly defined and identification techniques are discussed in detail. Besides going into detail about the genus Septoria s. str. , many septoria-like genera are discussed and clearly illustrated. Species include: This Capnodiales -related article
5022-406: The photoautotrophic algal partner generates metabolic energy through photosynthesis, the fungus offers a stable, supportive matrix and protects cells from radiation and dehydration. Around 42% of the Ascomycota (about 18,000 species) form lichens, and almost all the fungal partners of lichens belong to the Ascomycota. Fermenting Fermentation is a type of redox metabolism carried out in
5115-533: The Ascomycota have formed symbiotic associations with green algae ( Chlorophyta ), and other types of algae and cyanobacteria . These mutualistic associations are commonly known as lichens , and can grow and persist in terrestrial regions of the earth that are inhospitable to other organisms and characterized by extremes in temperature and humidity, including the Arctic , the Antarctic , deserts , and mountaintops. While
5208-1071: The Ascomycota. Ascomycota is a monophyletic group (containing all of the descendants of a common ancestor). Previously placed in the Basidiomycota along with asexual species from other fungal taxa, asexual (or anamorphic ) ascomycetes are now identified and classified based on morphological or physiological similarities to ascus-bearing taxa , and by phylogenetic analyses of DNA sequences. Ascomycetes are of particular use to humans as sources of medicinally important compounds such as antibiotics , as well as for fermenting bread, alcoholic beverages, and cheese. Examples of ascomycetes include Penicillium species on cheeses and those producing antibiotics for treating bacterial infectious diseases . Many ascomycetes are pathogens , both of animals, including humans, and of plants. Examples of ascomycetes that can cause infections in humans include Candida albicans , Aspergillus niger and several tens of species that cause skin infections . The many plant-pathogenic ascomycetes include apple scab , rice blast ,
5301-410: The Ascomycota. The most frequent types are the single-celled spores, which are designated amerospores . If the spore is divided into two by a cross-wall ( septum ), it is called a didymospore . When there are two or more cross-walls, the classification depends on spore shape. If the septae are transversal , like the rungs of a ladder, it is a phragmospore , and if they possess a net-like structure it
5394-629: The Ascomycota. These include the following sexual ( teleomorphic ) groups, defined by the structures of their sexual fruiting bodies : the Discomycetes , which included all species forming apothecia ; the Pyrenomycetes , which included all sac fungi that formed perithecia or pseudothecia , or any structure resembling these morphological structures; and the Plectomycetes, which included those species that form cleistothecia . Hemiascomycetes included
5487-537: The absence of oxygen . During fermentation, organic molecules (e.g., glucose ) are catabolized and donate electrons to other organic molecules. In the process, ATP and organic end products (e.g., lactate ) are formed. Because oxygen is not required, it is an alternative to aerobic respiration . Over 25% of bacteria and archaea carry out fermentation. They live in the gut , sediments , food , and other environments. Eukaryotes, including humans and other animals, also carry out fermentation. Fermentation
5580-527: The action of living microorganisms was a breakthrough, it did not explain the basic nature of fermentation; nor did it prove it is caused by microorganisms which appear to be always present. Many scientists, including Pasteur, had unsuccessfully attempted to extract the fermentation enzyme from yeast . Success came in 1897 when the German chemist Eduard Buechner ground up yeast, extracted a juice from them, then found to his amazement this "dead" liquid would ferment
5673-449: The atmosphere and freshwater environments, as well as ocean beaches and tidal zones. The distribution of species is variable; while some are found on all continents, others, as for example the white truffle Tuber magnatum , only occur in isolated locations in Italy and Eastern Europe. The distribution of plant-parasitic species is often restricted by host distributions; for example, Cyttaria
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#17328919027995766-692: The biochemical sense, but are called fermentation in the larger sense: Fermentation can be used to make alternative protein sources. It is commonly used to modify existing protein foods, including plant-based ones such as soy, into more flavorful forms such as tempeh and fermented tofu . More modern "fermentation" makes recombinant protein to help produce meat analogue , milk substitute , cheese analogues , and egg substitutes . Some examples are: Heme proteins such as myoglobin and hemoglobin give meat its characteristic texture, flavor, color, and aroma. The myoglobin and leghemoglobin ingredients can be used to replicate this property, despite them coming from
5859-755: The cell. Many species live on dead plant material such as leaves, twigs, or logs. Several species colonize plants, animals, or other fungi as parasites or mutualistic symbionts and derive all their metabolic energy in form of nutrients from the tissues of their hosts. Owing to their long evolutionary history, the Ascomycota have evolved the capacity to break down almost every organic substance. Unlike most organisms, they are able to use their own enzymes to digest plant biopolymers such as cellulose or lignin . Collagen , an abundant structural protein in animals, and keratin —a protein that forms hair and nails—, can also serve as food sources. Unusual examples include Aureobasidium pullulans , which feeds on wall paint, and
5952-405: The culture medium flows steadily through a tube while the cells are recycled from the outlet to the inlet. If the process works well, there is a steady flow of feed and effluent and the costs of repeatedly setting up a batch are avoided. Also, it can prolong the exponential growth phase and avoid byproducts that inhibit the reactions by continuously removing them. However, it is difficult to maintain
6045-417: The cuticle for dispersal. Asexual reproduction process in ascomycetes also involves the budding which we clearly observe in yeast. This is termed a "blastic process". It involves the blowing out or blebbing of the hyphal tip wall. The blastic process can involve all wall layers, or there can be a new cell wall synthesized which is extruded from within the old wall. The initial events of budding can be seen as
6138-605: The development of a ring of chitin around the point where the bud is about to appear. This reinforces and stabilizes the cell wall. Enzymatic activity and turgor pressure act to weaken and extrude the cell wall. New cell wall material is incorporated during this phase. Cell contents are forced into the progeny cell, and as the final phase of mitosis ends a cell plate, the point at which a new cell wall will grow inwards from, forms. There are three subphyla that are described and accepted: Several outdated taxon names—based on morphological features—are still occasionally used for species of
6231-494: The development of new processes for producing high-value products like antibiotics and enzymes, the increasing importance of fermentation in the production of bulk chemicals, and a growing interest in the use of fermentation for the production of functional foods and nutraceuticals. The 1950s and 1960s saw the development of new fermentation technologies, such as the use of immobilized cells and enzymes, which allowed for more precise control over fermentation processes and increased
6324-473: The difficulty of maintaining sterility, can be met. In a batch process, all the ingredients are combined and the reactions proceed without any further input. Batch fermentation has been used for millennia to make bread and alcoholic beverages, and it is still a common method, especially when the process is not well understood. However, it can be expensive because the fermentor must be sterilized using high pressure steam between batches. Strictly speaking, there
6417-411: The end-product is mostly lactic acid, or heterolactic fermentation , where some lactate is further metabolized to ethanol and carbon dioxide (via the phosphoketolase pathway), acetate, or other metabolic products, e.g.: If lactose is fermented (as in yogurts and cheeses), it is first converted into glucose and galactose (both six-carbon sugars with the same atomic formula): Heterolactic fermentation
6510-407: The ends of specialized hyphae, the conidiophores. Depending on the species they may be dispersed by wind or water, or by animals. Conidiophores may simply branch off from the mycelia or they may be formed in fruiting bodies. The hypha that creates the sporing (conidiating) tip can be very similar to the normal hyphal tip, or it can be differentiated. The most common differentiation is the formation of
6603-462: The fermentor between batches can be avoided using various open fermentation approaches that are able to resist contamination. One is to use a naturally evolved mixed culture. This is particularly favored in wastewater treatment, since mixed populations can adapt to a wide variety of wastes. Thermophilic bacteria can produce lactic acid at temperatures of around 50 °Celsius, sufficient to discourage microbial contamination; and ethanol has been produced at
6696-663: The fungal symbiont directly obtains products of photosynthesis . In common with many basidiomycetes and Glomeromycota , some ascomycetes form symbioses with plants by colonizing the roots to form mycorrhizal associations. The Ascomycota also represents several carnivorous fungi , which have developed hyphal traps to capture small protists such as amoebae , as well as roundworms ( Nematoda ), rotifers , tardigrades , and small arthropods such as springtails ( Collembola ). The Ascomycota are represented in all land ecosystems worldwide, occurring on all continents including Antarctica . Spores and hyphal fragments are dispersed through
6789-428: The fungi and correspond roughly to the sexes in plants and animals; however one species may have more than two mating types, resulting in sometimes complex vegetative incompatibility systems. The adaptive function of mating type is discussed in Neurospora crassa . Gametangia are sexual structures formed from hyphae, and are the generative cells. A very fine hypha, called trichogyne emerges from one gametangium,
6882-517: The group its name. Asexual reproduction is the dominant form of propagation in the Ascomycota, and is responsible for the rapid spread of these fungi into new areas. Asexual reproduction of ascomycetes is very diverse from both structural and functional points of view. The most important and general is production of conidia, but chlamydospores are also frequently produced. Furthermore, Ascomycota also reproduce asexually through budding. Asexual reproduction may occur through vegetative reproductive spores,
6975-518: The hook with one nucleus, one at the basal of the original hypha that contains one nucleus, and one that separates the U-shaped part, which contains the other two nuclei. Fusion of the nuclei (karyogamy) takes place in the U-shaped cells in the hymenium, and results in the formation of a diploid zygote . The zygote grows into the ascus , an elongated tube-shaped or cylinder-shaped capsule. Meiosis then gives rise to four haploid nuclei, usually followed by
7068-446: The hyphae, called " septa ", are the internal boundaries of individual cells (or compartments). The cell wall and septa give stability and rigidity to the hyphae and may prevent loss of cytoplasm in case of local damage to cell wall and cell membrane . The septa commonly have a small opening in the center, which functions as a cytoplasmic connection between adjacent cells, also sometimes allowing cell-to-cell movement of nuclei within
7161-416: The hyphae. The two nuclei contained in the apical part of each hypha divide in such a way that the threads of their mitotic spindles run parallel, creating two pairs of genetically different nuclei. One daughter nucleus migrates close to the hook, while the other daughter nucleus locates to the basal part of the hypha. The formation of two parallel cross-walls then divides the hypha into three sections: one at
7254-612: The kerosene fungus Amorphotheca resinae , which feeds on aircraft fuel (causing occasional problems for the airline industry), and may sometimes block fuel pipes. Other species can resist high osmotic stress and grow, for example, on salted fish, and a few ascomycetes are aquatic. The Ascomycota is characterized by a high degree of specialization; for instance, certain species of Laboulbeniales attack only one particular leg of one particular insect species. Many Ascomycota engage in symbiotic relationships such as in lichens—symbiotic associations with green algae or cyanobacteria —in which
7347-402: The mycelium from which they originate. They are typically formed at the ends of specialized hyphae , the conidiophores . Depending on the species they may be dispersed by wind or water, or by animals. Different types of asexual spores can be identified by colour, shape, and how they are released as individual spores. Spore types can be used as taxonomic characters in the classification within
7440-436: The original parent nuclei. Alternatively, nuclei may lose some chromosomes, resulting in aneuploid cells. Candida albicans (class Saccharomycetes) is an example of a fungus that has a parasexual cycle (see Candida albicans and Parasexual cycle ). Sexual reproduction in the Ascomycota leads to the formation of the ascus , the structure that defines this fungal group and distinguishes it from other fungal phyla. The ascus
7533-413: The parent structure). Conidiogenesis corresponds to Embryology in animals and plants and can be divided into two fundamental forms of development: blastic conidiogenesis, where the spore is already evident before it separates from the conidiogenic hypha, and thallic conidiogenesis, during which a cross-wall forms and the newly created cell develops into a spore. The spores may or may not be generated in
7626-472: The pellicles or moldy layers that develop on jams, juices, and other foods are the mycelia of these species or occasionally Mucoromycotina and almost never Basidiomycota . Sooty molds that develop on plants, especially in the tropics are the thalli of many species. Large masses of yeast cells, asci or ascus-like cells, or conidia can also form macroscopic structures. For example. Pneumocystis species can colonize lung cavities (visible in x-rays), causing
7719-407: The present. For example, in the 1930s, it was discovered microorganisms could be mutated with physical and chemical treatments to be higher-yielding, faster-growing, tolerant of less oxygen, and able to use a more concentrated medium. Strain selection and hybridization developed as well, affecting most modern food fermentations. The field of fermentation has been critical to the production of
7812-656: The process of heterokaryosis, caused by merging of two hyphae belonging to different individuals, by a process called anastomosis , followed by a series of events resulting in genetically different cell nuclei in the mycelium . The merging of nuclei is not followed by meiotic events , such as gamete formation and results in an increased number of chromosomes per nuclei. Mitotic crossover may enable recombination , i.e., an exchange of genetic material between homologous chromosomes . The chromosome number may then be restored to its haploid state by nuclear division , with each daughter nuclei being genetically different from
7905-519: The process of manufacturing rather than metabolic details. Fermentation is used by organisms to generate ATP energy for metabolism. One advantage is that it requires no oxygen or other external electron acceptors, and thus it can be carried when those electron acceptors are absent. A disadvantage is that it produces relatively little ATP, yielding only between 2 and 4.5 per glucose compared to 32 for aerobic respiration. Over 25% of bacteria and archaea carry out fermentation. This type of metabolism
7998-403: The production of high-value products like antibiotics and enzymes. In the 1970s and 1980s, fermentation became increasingly important in the production of bulk chemicals like ethanol, lactic acid, and citric acid. This led to the development of new fermentation techniques and the use of genetically engineered microorganisms to improve yields and reduce production costs. In the 1990s and 2000s, there
8091-759: The same species. Species of the Deuteromycota were classified as Coelomycetes if they produced their conidia in minute flask- or saucer-shaped conidiomata, known technically as pycnidia and acervuli . The Hyphomycetes were those species where the conidiophores ( i.e. , the hyphal structures that carry conidia-forming cells at the end) are free or loosely organized. They are mostly isolated but sometimes also appear as bundles of cells aligned in parallel (described as synnematal ) or as cushion-shaped masses (described as sporodochial ). Most species grow as filamentous, microscopic structures called hyphae or as budding single cells (yeasts). Many interconnected hyphae form
8184-514: The spores reach a suitable substrate, they germinate, form new hyphae, which restarts the fungal life cycle. The form of the ascus is important for classification and is divided into four basic types: unitunicate-operculate, unitunicate-inoperculate, bitunicate, or prototunicate. See the article on asci for further details. The Ascomycota fulfil a central role in most land-based ecosystems . They are important decomposers , breaking down organic materials, such as dead leaves and animals, and helping
8277-409: The thallus of the fungus defines the shape of the symbiotic colony. Some dimorphic species, such as Candida albicans , can switch between growth as single cells and as filamentous, multicellular hyphae. Other species are pleomorphic , exhibiting asexual (anamorphic) as well as a sexual (teleomorphic) growth forms. Except for lichens, the non-reproductive (vegetative) mycelium of most ascomycetes
8370-822: The yeasts and yeast-like fungi that have now been placed into the Saccharomycotina or Taphrinomycotina , while the Euascomycetes included the remaining species of the Ascomycota, which are now in the Pezizomycotina , and the Neolecta , which are in the Taphrinomycotina. Some ascomycetes do not reproduce sexually or are not known to produce asci and are therefore anamorphic species. Those anamorphs that produce conidia (mitospores) were previously described as mitosporic Ascomycota . Some taxonomists placed this group into
8463-419: Was a growing interest in the use of fermentation for the production of functional foods and nutraceuticals, which have potential health benefits beyond basic nutrition. This led to the development of new fermentation processes and the use of probiotics and other functional ingredients. Overall, the period from 1930 onward saw significant advancements in the use of fermentation for industrial purposes, leading to
8556-443: Was lampooned in an anonymous publication by Justus von Liebig and Friedrich Wöhler . The turning point came when Louis Pasteur (1822–1895), during the 1850s and 1860s, repeated Schwann's experiments and showed fermentation is initiated by living organisms in a series of investigations. In 1857, Pasteur showed lactic acid fermentation is caused by living organisms. In 1860, he demonstrated how bacteria cause souring in milk,
8649-585: Was not until the California Gold Rush in the 1850s that ethanol was first used as a fuel in the United States. Rudolf Diesel demonstrated his engine, which could run on vegetable oils and ethanol, in 1895, but the widespread use of petroleum-based diesel engines made ethanol less popular as a fuel. In the 1970s, the oil crisis reignited interest in ethanol, and Brazil became a leader in ethanol production and use. The United States began producing ethanol on
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