Brief Summary

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Aspergillus niger is a member of the genus Aspergillus which includes a set of fungi that are generally considered asexual, although perfect forms (forms that reproduce sexually) have been found. Aspergilli are ubiquitous in nature. They are geographically widely distributed, and have been observed in a broad range of habitats because they can colonize a wide variety of substrates. A. niger is commonly found as a saprophyte growing on dead leaves, stored grain, compost piles, and other decaying vegetation. The spores are widespread, and are often associated with organic materials and soil. The primary uses of A. niger are for the production of enzymes and organic acids by fermentation. A. niger is also used to produce organic acids such as citric acid and gluconic acid.

Morphology

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While morphology provides a reasonable means of classification and assignment within the A. niger group, it is not a reliable means for identifying a given isolate from the field. The major distinction currently separating A. niger from the other species of Aspergillus is the production of carbon black or very dark brown spores from biseriate phialides (Raper and Fennell, 1965). Other features include the smooth and generally colorless conidiophores and spores that are ó5 æm, globose, and have conspicuous ridges or spines not arranged in rows. A. niger isolates grow slowly on Czapek agar (Raper and Fennell, 1965). These physical characters such as spore color and rate of growth on a defined media are subject to change, especially under extended pure culture or selection and mutation. Though A. niger is relatively stable to spontaneous mutation compared to other aspergilli, variation in morphology may still be a problem with some strains (Raper and Fennell, 1965). Thus this species may be misidentified with other Aspergillus spp.

Risks

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Aspergillus niger is worldwide in distribution and has been isolated from numerous habitats. Humans are continually exposed to A. niger spores and vegetative forms on foodstuffs and in the air. The vast majority of strains of A. niger, especially those used in industrial fermentation, have a history of safe use. While there are sporadic reports to the contrary, most isolates have not been documented to be serious pathogens of humans, animals or plants. Specific strains may produce certain mycotoxins or may elicit allergic responses among workers. Those limited instances of adverse effects seem to be associated with a limited number of strains. With proper characterization of industrial strains, use of those with potential for such effects can be avoided.

Diagnostic Description

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Distinguishing the organism from other species of Aspergillus can be done macroscopically, by identifying the white felt like colony turning black with conidia formation. Microscopically one can confirm this identification by the presence of black, globose conidia with very dark to black spores.

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Distribution

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Since A. niger is so ubiquitous, you can expect to find this fungus almost anywhere. A. niger has been found to be thermotolerant and have shown a tolerance to freezing, further indicating that this fungus can be found nearly anywhere.

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General Description

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Aspergillus niger can be classified as a member of the “deuteromycetes,” a “class” reserved for organisms with no known sexual state. Although they are considered a deuteromycete, modern taxonomy puts them in the phlyum of Ascomycota. Further taxonomy takes A. niger to the class of Eurotiomycetes, order of Eurotiales, family of Trichocomaceae, and genus Aspergillus.

A. niger is a ubiquitous fungus that grows very quickly. Strains can be isolated from many different ecological habitats such as soil, plant debris, rotting fruit, and even indoor air environments.

Macroscopically, this fungus can be identified growing on substrates producing colonies of felt like yellow to white hyphae, turning black with the formation of conidia.

Microscopically, A. niger can be identified by its hyaline, septate hyphae. Asexual conidiophores can be identified by being long and globose at the tip, with what appears to be a hymenial layer of structures, each “ejecting” its own spore.

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Habitat

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As previously stated, A. niger is very ubiquitous and lives in nearly all environments. Common environments include soil, plant debri, indoor environments. It has been found on rotting fruit and vegetables as well.

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Look Alikes

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Other species of Aspergillus have been confused with A. niger but the black conidia and spores confirm the species to be A. niger. Also, some people confuse some species of Penicillium with Aspergillus. This confusion can be easily settled by looking at the organisms microscopically. Penicillium has a paint brush looking conidium, while a Aspergillus looks more like a toilet brush, with its globose base at the end of the stalk. Stachybotrys also is confused with Aspergillus as they both grow as black colonies, but further identification at the microscopic level shows the conidial structure to be different than A. niger

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Uses

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A. niger is one of the most valuable fungi to humans. A. niger makes citric acid, the main ingredient in soda. Most people think citric acid is gathered from grinding citrus fruits, but that would be very expensive. Most citric acid is collected from fermenters of A. niger growing and secreting citric acid. The citric acid production by A. niger for soda is a multi million dollar operation!

See Tom Volk’s Aspergillus page

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Aspergillus niger

provided by wikipedia EN

Aspergillus niger is a fungus and one of the most common species of the genus Aspergillus.

It causes a disease called "black mold" on certain fruits and vegetables such as grapes, apricots, onions, and peanuts, and is a common contaminant of food. It is ubiquitous in soil and is commonly reported from indoor environments, where its black colonies can be confused with those of Stachybotrys (species of which have also been called "black mold").[1]

Some strains of A. niger have been reported to produce potent mycotoxins called ochratoxins;[2] other sources disagree, claiming this report is based upon misidentification of the fungal species. Recent evidence suggests some true A. niger strains do produce ochratoxin A.[1][3] It also produces the isoflavone orobol.

Taxonomy

Aspergillus niger is included in Aspergillus subgenus Circumdati, section Nigri. The section Nigri includes 15 related black-spored species that may be confused with A. niger, including A. tubingensis, A. foetidus, A. carbonarius, and A. awamori.[4][5] In 2004 a number of morphologically similar species were described by Samson et al.[5]

In 2007 the strain of ATCC 16404 Aspergillus niger was reclassified as Aspergillus brasiliensis (refer to publication by Varga et al.[6]). This has required an update to the U.S. Pharmacopoeia and the European Pharmacopoeia which commonly use this strain throughout the pharmaceutical industry.

Pathogenicity

Plant disease

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A. niger growing on onion

Aspergillus niger causes sooty mold of onions and ornamental plants. Infection of onion seedlings by A. niger can become systemic, manifesting only when conditions are conducive. A. niger causes a common postharvest disease of onions, in which the black conidia can be observed between the scales of the bulb. The fungus also causes disease in peanuts and in grapes.

Human and animal disease

Aspergillus niger is less likely to cause human disease than some other Aspergillus species. In extremely rare instances, humans may become ill, but this is due to a serious lung disease, aspergillosis, that can occur. Aspergillosis is, in particular, frequent among horticultural workers who inhale peat dust, which can be rich in Aspergillus spores. The fungus has also been found in the mummies of ancient Egyptian tombs and can be inhaled when they are disturbed.[7]

A. niger is one of the most common causes of otomycosis (fungal ear infections), which can cause pain, temporary hearing loss, and, only in severe cases, damage to the ear canal and tympanic membrane.

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A. niger growing on PDA

Cultivation

A. niger has been cultivated both on Czapek medium plates and malt extract agar Oxoid (MEAOX) plates.

Industrial uses

Aspergillus niger is cultured for the industrial production of many substances.[8] Various strains of A. niger are used in the industrial preparation of citric acid (E330) and gluconic acid (E574), and have been assessed as acceptable for daily intake by the World Health Organization.[9] A. niger fermentation is "generally recognized as safe" (GRAS) by the United States Food and Drug Administration under the Federal Food, Drug, and Cosmetic Act.[10] A. niger is also considered as a potential alternative source of natural food grade pigments.[11]

Many useful enzymes are produced using industrial fermentation of A. niger.[12] For example, A. niger glucoamylase () is used in the production of high-fructose corn syrup, and pectinases (GH28) are used in cider and wine clarification. Alpha-galactosidase (GH27), an enzyme that breaks down certain complex sugars, is a component of Beano and other products that decrease flatulence.[13] Another use for A. niger within the biotechnology industry is in the production of magnetic isotope-containing variants of biological macromolecules for NMR analysis.[14] Aspergillus niger is also cultured for the extraction of the enzyme, glucose oxidase (), used in the design of glucose biosensors, due to its high affinity for β-D-glucose.[15][16]

Aspergillus niger growing in gold-mining solutions contained cyano-metal complexes with gold, silver, copper, iron, and zinc. The fungus also plays a role in the solubilization of heavy-metal sulfides.[17] Alkali-treated A. niger binds to silver to 10% of dry weight. Silver biosorption occurs by stoichiometric exchange with Ca(II) and Mg(II) of the sorbent.

Genetics

Genome

The A. niger ATCC 1015 genome was sequenced by the Joint Genome Institute in a collaboration with other institutions.[18]

The genomes of two A. niger strains have been fully sequenced.[19][20]

See also

References

  1. ^ a b Samson RA, Houbraken J, Summerbell RC, Flannigan B, Miller JD (2001). "Common and important species of fungi and actinomycetes in indoor environments". Microorganisms in Home and Indoor Work Environments. CRC. pp. 287–292. ISBN 978-0415268004.
  2. ^ Abarca M, Bragulat M, Castellá G, Cabañes F (1994). "Ochratoxin A production by strains of Aspergillus niger var. niger". Appl Environ Microbiol. 60 (7): 2650–2. doi:10.1128/AEM.60.7.2650-2652.1994. PMC 201698. PMID 8074536.
  3. ^ Schuster E, Dunn-Coleman N, Frisvad JC, Van Dijck PW (2002). "On the safety of Aspergillus niger—a review". Applied Microbiology and Biotechnology. 59 (4–5): 426–35. doi:10.1007/s00253-002-1032-6. PMID 12172605. S2CID 26113037.
  4. ^ Klich MA (2002). Identification of common Aspergillus species. Utrecht, The Netherlands, Centraalbureau voor Schimmelcultures. ISBN 978-90-70351-46-5.
  5. ^ a b Samson, RA, Houbraken JA, Kuijpers AF, Frank JM, Frisvad JC (2004). "New ochratoxin A or sclerotium producing species in Aspergillus section Nigri" (PDF). Studies in Mycology. 50: 45–6.
  6. ^ Varga, J.; Kocsube, S.; Toth, B.; Frisvad, J. C.; Perrone, G.; Susca, A.; Meijer, M.; Samson, R. A. (2007). "Aspergillus brasiliensis sp. nov., a biseriate black Aspergillus species with world-wide distribution". International Journal of Systematic and Evolutionary Microbiology. 57 (8): 1925–32. doi:10.1099/ijs.0.65021-0. PMID 17684283.
  7. ^ Handwerk, Brian (May 6, 2005) Egypt's "King Tut Curse" Caused by Tomb Toxins?. National Geographic.
  8. ^ Cairns, TC; Nai, C; Meyer, V (2018). "How a fungus shapes biotechnology: 100 years of Aspergillus niger research". Fungal Biology and Biotechnology. 5: 13. doi:10.1186/s40694-018-0054-5. ISSN 2054-3085. PMC 5966904. PMID 29850025.
  9. ^ Max, Belén; Salgado, José Manuel; Rodríguez, Noelia; Cortés, Sandra; Converti, Attilio; Domínguez, José Manuel (October 2010). "Biotechnological production of citric acid". Brazilian Journal of Microbiology. 41 (4): 862–875. doi:10.1590/S1517-83822010000400005. ISSN 1517-8382. PMC 3769771. PMID 24031566.
  10. ^ "Inventory of GRAS Notices: Summary of all GRAS Notices". US FDA/CFSAN. 2008-10-22. Archived from the original on 11 October 2008. Retrieved 2008-10-31.
  11. ^ Toma, Maria Afroz; Nazir, K. H. M. Nazmul Hussain; Mahmud, Md Muket; Mishra, Pravin; Ali, Md Kowser; Kabir, Ajran; Shahid, Md Ahosanul Haque; Siddique, Mahbubul Pratik; Alim, Md Abdul (2021). "Isolation and Identification of Natural Colorant Producing Soil-Borne Aspergillus niger from Bangladesh and Extraction of the Pigment". Foods. 10 (6): 1280. doi:10.3390/foods10061280.
  12. ^ Ong, L. G. A.; Abd-Aziz, S.; Noraini, S.; Karim, M. I. A.; Hassan, M. A. (2004). "Enzyme Production and Profile by Aspergillus niger During Solid Substrate Fermentation Using Palm Kernel Cake as Substrate". Applied Biochemistry and Biotechnology. 118 (1–3): 073–080. doi:10.1385/ABAB:118:1-3:073. ISSN 0273-2289. PMID 15304740. S2CID 19063403.
  13. ^ Di Stefano, Michele; Miceli, Emanuela; Gotti, Samantha; Missanelli, Antonio; Mazzocchi, Samanta; Corazza, Gino Roberto (2007). "The effect of oral alpha-galactosidase on intestinal gas production and gas-related symptoms". Digestive Diseases and Sciences. 52 (1): 78–83. doi:10.1007/s10620-006-9296-9. ISSN 0163-2116. PMID 17151807. S2CID 35435660.
  14. ^ MacKenzie, D. A.; Spencer, J. A.; Le Gal-Coëffet, M. F.; Archer, D. B. (1996-04-30). "Efficient production from Aspergillus niger of a heterologous protein and an individual protein domain, heavy isotope-labelled, for structure-function analysis". Journal of Biotechnology. 46 (2): 85–93. doi:10.1016/0168-1656(95)00179-4. ISSN 0168-1656. PMID 8672288.
  15. ^ Staiano, M.; Bazzicalupo, P.; Rossi, M.; d'Auria, S. (2005). "Glucose biosensors as models for the development of advanced protein-based biosensors". Molecular BioSystems. 1 (5–6): 354–362. doi:10.1039/b513385h. PMID 16881003.
  16. ^ Ghoshdastider U, Wu R, Trzaskowski B, Mlynarczyk K, Miszta P, Gurusaran M, Viswanathan S, Renugopalakrishnan V, Filipek S (2015). "Nano-Encapsulation of Glucose Oxidase Dimer by Graphene". RSC Advances. 5 (18): 13570–78. doi:10.1039/C4RA16852F. S2CID 55816037.
  17. ^ Singh, Harbhajan (2006). Mycoremediation: Fungal Bioremediation. John Wiley & Sons. p. 509. ISBN 978-0470050583.
  18. ^ "Home – Aspergillus niger ATCC 1015 v4.0".
  19. ^ Pel H, de Winde J, Archer D, et al. (2007). "Genome sequencing and analysis of the versatile cell factory Aspergillus niger CBS 513.88". Nat Biotechnol. 25 (2): 221–31. doi:10.1038/nbt1282. PMID 17259976.
  20. ^ Andersen MR, Salazar MP, Schaap PJ, et al. (2011). "Comparative genomics of citric-acid-producing Aspergillus niger ATCC 1015 versus enzyme-producing CBS 513.88". Genome Res. 21 (6): 885–97. doi:10.1101/gr.112169.110. PMC 3106321. PMID 21543515.

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Aspergillus niger: Brief Summary

provided by wikipedia EN

Aspergillus niger is a fungus and one of the most common species of the genus Aspergillus.

It causes a disease called "black mold" on certain fruits and vegetables such as grapes, apricots, onions, and peanuts, and is a common contaminant of food. It is ubiquitous in soil and is commonly reported from indoor environments, where its black colonies can be confused with those of Stachybotrys (species of which have also been called "black mold").

Some strains of A. niger have been reported to produce potent mycotoxins called ochratoxins; other sources disagree, claiming this report is based upon misidentification of the fungal species. Recent evidence suggests some true A. niger strains do produce ochratoxin A. It also produces the isoflavone orobol.

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