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Peroxidases or peroxide reductases are a large group of enzymes which play a role in various biological processes. They are named after the fact that they commonly break up peroxides.
Lignin is a class of complex organic polymers that form key structural materials in the support tissues of most plants. Lignins are particularly important in the formation of cell walls, especially in wood and bark, because they lend rigidity and do not rot easily. Chemically, lignins are polymers made by cross-linking phenolic precursors.
Cellulase is any of several enzymes produced chiefly by fungi, bacteria, and protozoans that catalyze cellulolysis, the decomposition of cellulose and of some related polysaccharides. The name is also used for any naturally occurring mixture or complex of various such enzymes, that act serially or synergistically to decompose cellulosic material.
An exoenzyme, or extracellular enzyme, is an enzyme that is secreted by a cell and functions outside that cell. Exoenzymes are produced by both prokaryotic and eukaryotic cells and have been shown to be a crucial component of many biological processes. Most often these enzymes are involved in the breakdown of larger macromolecules. The breakdown of these larger macromolecules is critical for allowing their constituents to pass through the cell membrane and enter into the cell. For humans and other complex organisms, this process is best characterized by the digestive system which breaks down solid food via exoenzymes. The small molecules, generated by the exoenzyme activity, enter into cells and are utilized for various cellular functions. Bacteria and fungi also produce exoenzymes to digest nutrients in their environment, and these organisms can be used to conduct laboratory assays to identify the presence and function of such exoenzymes. Some pathogenic species also use exoenzymes as virulence factors to assist in the spread of these disease-causing microorganisms. In addition to the integral roles in biological systems, different classes of microbial exoenzymes have been used by humans since pre-historic times for such diverse purposes as food production, biofuels, textile production and in the paper industry. Another important role that microbial exoenzymes serve is in the natural ecology and bioremediation of terrestrial and marine environments.
Industrial fermentation is the intentional use of fermentation by microorganisms such as bacteria and fungi as well as eukaryotic cells like CHO cells and insect cells, to make products useful to humans. Fermented products have applications as food as well as in general industry. Some commodity chemicals, such as acetic acid, citric acid, and ethanol are made by fermentation. The rate of fermentation depends on the concentration of microorganisms, cells, cellular components, and enzymes as well as temperature, pH and for aerobic fermentation oxygen. Product recovery frequently involves the concentration of the dilute solution. Nearly all commercially produced enzymes, such as lipase, invertase and rennet, are made by fermentation with genetically modified microbes. In some cases, production of biomass itself is the objective, like Single-cell protein and as in the case of baker's yeast and lactic acid bacteria starter cultures for cheesemaking. In general, fermentations can be divided into four types:
Mycoremediation is a form of bioremediation in which fungi-based remediation methods are used to decontaminate the environment. Fungi have been proven to be a cheap, effective and environmentally sound way for removing a wide array of contaminants from damaged environments or wastewater. These contaminants include heavy metals, organic pollutants, textile dyes, leather tanning chemicals and wastewater, petroleum fuels, polycyclic aromatic hydrocarbons, pharmaceuticals and personal care products, pesticides and herbicides in land, fresh water, and marine environments. The byproducts of the remediation can be valuable materials themselves, such as enzymes, edible or medicinal mushrooms, making the remediation process even more profitable. Some fungi are useful in the biodegradation of contaminants in extremely cold or radioactive environments where traditional remediation methods prove too costly or are unusable due to the extreme conditions. Mycoremediation can even be used for fire management with the encapsulation method. This process consists of using fungal spores coated with agarose in a pellet form. This pellet is introduced to a substrate in the burnt forest, breaking down the toxins in the environment and stimulating growth.
Laccases are multicopper oxidases found in plants, fungi, and bacteria. Laccases oxidize a variety of phenolic substrates, performing one-electron oxidations, leading to crosslinking. For example, laccases play a role in the formation of lignin by promoting the oxidative coupling of monolignols, a family of naturally occurring phenols. Other laccases, such as those produced by the fungus Pleurotus ostreatus, play a role in the degradation of lignin, and can therefore be classed as lignin-modifying enzymes. Other laccases produced by fungi can facilitate the biosynthesis of melanin pigments. Laccases catalyze ring cleavage of aromatic compounds.
A wood-decay or xylophagous fungus is any species of fungus that digests moist wood, causing it to rot. Some species of wood-decay fungi attack dead wood, such as brown rot, and some, such as Armillaria, are parasitic and colonize living trees. Excessive moisture above the fibre saturation point in wood is required for fungal colonization and proliferation. Fungi that not only grow on wood but permeate its fibrous structure and actually cause decay, are called lignicolous fungi. In nature, this process causes the breakdown of complex molecules and leads to the return of nutrients to the soil. Various lignicolous fungi consume wood in various ways; for example, some attack the carbohydrates in wood and some others decay lignin. The rate of decay of wooden materials in various climates can be estimated by empirical models.
Coriolopsis gallica is a fungus found growing on decaying wood. It is not associated with any plant disease, therefore it is not considered pathogenic. For various Coriolopsis gallica strains isolated, it has been found, as a common feature of the division Basidiomycota, that they are able to degrade wood components, mainly lignin and to lesser extent cellulose, which results in a degradation area covered by the accumulating -white- cellulose powder. Therefore, C. gallica might generically be called, as with many other Basidiomycetes, a "white-rot" fungus.
In enzymology, a lignin peroxidase (EC 1.11.1.14) is an enzyme that catalyzes the chemical reaction
In enzymology, a manganese peroxidase (EC 1.11.1.13) is an enzyme that catalyzes the chemical reaction
Daedalea quercina is a species of mushroom in the order Polyporales, and the type species of the genus Daedalea. Commonly known as the oak mazegill or maze-gill fungus, the specific epithet refers to the oak genus Quercus, upon which it frequently grows, causing a brown rot. It is found in Europe, Asia, Northern Africa and Australasia. Though inedible, it can be used as a natural comb and has been the subject of chemical research.
Cyathus is a genus of fungi in the Nidulariaceae, a family collectively known as the bird's nest fungi. They are given this name since they resemble tiny bird's nests filled with "eggs", structures large enough to have been mistaken in the past for seeds. However, these are now known to be reproductive structures containing spores. The "eggs", or peridioles, are firmly attached to the inner surface of this fruit body by an elastic cord of mycelia known as a funiculus. The 45 species are widely distributed throughout the world and some are found in most countries, although a few exist in only one or two locales. Cyathus stercoreus is considered endangered in a number of European countries. Species of Cyathus are also known as splash cups, which refers to the fact that falling raindrops can knock the peridioles out of the open-cup fruit body. The internal and external surfaces of this cup may be ridged longitudinally ; this is one example of a taxonomic characteristic that has traditionally served to distinguish between species.
Cyathus stercoreus, commonly known as the dung-loving bird's nest, is a species of fungus in the genus Cyathus, family Nidulariaceae. Like other species in the Nidulariaceae, the fruiting bodies of C. stercoreus resemble tiny bird's nests filled with eggs. The fruiting bodies are referred to as splash cups, because they are developed to use the force of falling drops of water to dislodge and disperse their spores. The species has a worldwide distribution, and prefers growing on dung, or soil containing dung; the specific epithet is derived from the Latin word stercorarius, meaning "of dung".
Haem peroxidases (or heme peroxidases) are haem-containing enzymes that use hydrogen peroxide as the electron acceptor to catalyse a number of oxidative reactions. Most haem peroxidases follow the reaction scheme:
In molecular biology, the DyP-type peroxidase family is a family of haem peroxidase enzymes. Haem peroxidases were originally divided into two superfamilies, namely, the animal peroxidases and the plant peroxidases, which include fungal and bacterial peroxidases. The DyP family constitutes a novel class of haem peroxidase. Because these enzymes were derived from fungal sources, the DyP family was thought to be structurally related to the class II secretory fungal peroxidases. However, the DyP family exhibits only low sequence similarity to classical fungal peroxidases, such as LiP and MnP, and does not contain the conserved proximal and distal histidines and an essential arginine found in other plant peroxidase superfamily members.
Dye-decolorizing peroxidase (EC 1.11.1.19, DyP, DyP-type peroxidase) is an enzyme with systematic name Reactive-Blue-5:hydrogen-peroxide oxidoreductase. This enzyme catalyses the following chemical reaction
Myceliophthora thermophila is an ascomycete fungus that grows optimally at 45–50 °C (113–122 °F). It efficiently degrades cellulose and is of interest in the production of biofuels. The genome has recently been sequenced, revealing the full range of enzymes this organism uses for the degradation of plant cell wall material.
Extracellular enzymes or exoenzymes are synthesized inside the cell and then secreted outside the cell, where their function is to break down complex macromolecules into smaller units to be taken up by the cell for growth and assimilation. These enzymes degrade complex organic matter such as cellulose and hemicellulose into simple sugars that enzyme-producing organisms use as a source of carbon, energy, and nutrients. Grouped as hydrolases, lyases, oxidoreductases and transferases, these extracellular enzymes control soil enzyme activity through efficient degradation of biopolymers.
Hypsizygus ulmarius, also known as the elm oyster mushroom, and less commonly as the elm leech, elm Pleurotus, or blue oyster mushroom, is an edible fungus. It has often been confused with oyster mushrooms in the Pleurotus genus but can be differentiated easily as the gills are either not decurrent or not deeply decurrent. While not quite as common as true oyster mushrooms, they have a wide range globally in temperate forests. The mushrooms and vegetative hyphae of this species have been studied in recent years for their potential benefits to human health, and mycoremediation.
References
- 1 2 3 4 5 6 7 8 de Gonzalo, Gonzalo; Colpa, Dana I.; Habibi, Mohamed H. M.; Fraaije, Marco W. (16 August 2016). "Bacterial enzymes involved in lignin degradation". Journal of Biotechnology. 236: 110–119. doi: 10.1016/j.jbiotec.2016.08.011 . PMID 27544286.
- ↑ Gonçalves, Luisa (1996). "Use of Laccase for Bleaching of Pulps and Treatment of Effluents". Enzymes for Pulp and Paper Processing. ACS Symposium Series. 655. ACS Publications. pp. 197–206. doi:10.1021/bk-1996-0655.ch015. ISBN 978-0-8412-3478-9.
- ↑ Martani, F.; Lotti, M.; Porro, D. (2017). "The importance of fermentative conditions for the biotechnological production of lignin modifying enzymes from white-rot fungi". FEMS Microbiol Lett. 364 (13). doi: 10.1093/femsle/fnx134 . PMID 28655193.
- ↑ Richard, Chandra; Na, Zhong (2016). "The influence of lignin on steam pretreatment and mechanical pulping of poplar wood to achieve high sugar recovery and ease of enzymatic hydrolysis". Bioresource Technology. 199: 135–141. doi:10.1016/j.biortech.2015.09.019. PMID 26391968.
- ↑ Dana, Colpa; Gonzalo, Gonzalo (2016). "Bacterial enzymes involved in lignin degradation" (PDF). Journal of Biotechnology. 236: 110–119. doi: 10.1016/j.jbiotec.2016.08.011 . PMID 27544286.
- ↑ Raghukumar, C.; D’Souza, T. (1999). "Lignin-Modifying Enzymes of Flavodon flavus, a Basidiomycete Isolated from a Coastal Marine Environment". AEM Journal. 65 (5): 2103–11. PMC 91304 . PMID 10224007.
- 1 2 Bugg, Timothy D.H.; Ahmad, Mark; Hardiman, Elizabeth M.; Singh, Rahul (June 2011). "The emerging role for bacteria in lignin degradation and bio-product formation". Current Opinion in Biotechnology. 22 (3): 394–400. doi:10.1016/j.copbio.2010.10.009. PMID 21071202.
- 1 2 Chowdhary, Pankaj; Chandra, Ram (2015). "Properties of bacterial laccases and their application in bioremediation of industrial wastes". Environmental Science: Processes & Impacts. 17 (2): 326–342. doi:10.1039/C4EM00627E. PMID 25590782.