Aspergillus niger

Taxobox
name = "Aspergillus niger"

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image_width = 270px
image_caption = Micrograph of "A. niger" grown on Sabouraud agar medium. 100x magnification.
domain = Eukaryota
regnum = Fungi
phylum = Ascomycota
subphylum = Pezizomycotina
classis = Eurotiomycetes
ordo = Eurotiales
familia = Trichocomaceae
genus = Aspergillus
species = "A. niger"
binomial = "Aspergillus niger"
binomial_authority = van Tieghem 1867

"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, 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").cite book | author = Samson RA, Houbraken J, Summerbell RC, Flannigan B, Miller JD | title = Common and important species of fungi and actinomycetes in indoor environments. In: Microogranisms in Home and Indoor Work Environments | pages = pp. 287-292 | publisher = New York: Taylor & Francis | year = 2001 | id = ISBN ]

Some strains of "A. niger" have been reported to produce potent mycotoxins called ochratoxins,cite journal |author=Abarca M, Bragulat M, Castellá G, Cabañes F |title=Ochratoxin A production by strains of Aspergillus niger var. niger |journal=Appl Environ Microbiol |volume=60 |issue=7 |pages=2650–2 |year=1994 |pmid=8074536] but [http://www.leatherheadfood.com/eman2/fsheet3.asp other sources] disagree, claiming the latter report is based upon misidentification of the fungal species. Genomic sequence comparisons have also led to the demonstration of another Fumonisins, another important mycotoxin Recent evidence suggests some true "A. niger" strains do produce ochratoxin A. [cite journal
author = E. Schuster, N. Dunn-Coleman, J. Frisvad, P. van Dijck
title = On the safety of Aspergillus niger - a review
journal = Applied Microbiology and Biotechnology
year = 2002
volume = 59
issue = 4-5
pages = 426–435
doi = 10.1007/s00253-002-1032-6]

Taxonomy

"A. 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".cite book | author = Klich MA | title = Identification of common Aspergillus species | edition = | publisher = Utrecht, The Netherlands, Centraalbureau voor Schimmelcultures | year = 2002 | id = ISBN 90-70351-46-3] cite journal | author = Samson, RA, Houbraken JAMP, Kuijpers AFA, Frank JM, Frisvad JC | title = New ochratoxin A or sclerotium producing species in Aspergillus section Nigri | journal = Studies in Mycology | year = 2004 | volume = 50 | pages = pp. 45–6 | url= ] A number of morphologically similar species were recently described by Samson "et al".

Pathogenicity

Plant disease

"A. niger" causes black mold of onions. 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

"A. niger" is less likely to cause human disease than some other "Aspergillus" species, but if large amounts of spores are inhaled, a serious lung disease, aspergillosis can occur. Aspergillosis is particularly frequent among horticultural workers who inhale peat dust, which can be rich in "Aspergillus" spores . Less commonly, it has been found on the walls of ancient Egyptian tombs and can be inhaled when the area is disturbed.Fact|date=July 2008 "A. niger" is one of the most common causes of otomycosis (fungal ear infections), which can cause pain, temporary hearing loss and, in severe cases, damage to the ear canal and tympanic membrane.

Industrial uses

"A. niger" is cultured for the industrial production of many substances. 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 Organisation.

Many useful enzymes are produced using industrial fermentation of "A. niger". For example, "A. niger" glucoamylase is used in the production of high fructose corn syrup, and pectinases are used in cider and wine clarification. α-galactosidase, an enzyme that breaks down certain complex sugars, is a component of Beano and other medications which the manufacturers claim can decrease flatulence. Another use for "A. niger" within the biotechnology industry is in the production of magnetic isotope-containing variants of biological macromolecules for NMR analysis.

Lately it has also been used as a source for vegetarian glucosamine.

Other uses

In 2006 it was reported that a secreted RNase produced by "A. niger" called "actibind" has antiangiogenic and anticarcinogenic characteristics.

"A. niger" is also cultured for the extraction of the enzymes glucose oxidase (GO) and Alpha-galactosidase (AGS). Glucose oxidase is used in the design of glucose biosensors, due to its high affinity for β-D-glucose. [Staiano, Maria, Paolo Bazzicalupo, Mose' Rossi, and Sabato D'Auria. “Glucose biosensors as models for the development of advanced protein-based biosensors.” Molecular BioSystems 1 (2005): 354-362.] Alpha-galactosidase can be produced by "A. niger" fermentation; it is used to hydrolyze alpha 1-6 bonds found in melibiose, raffinose, and stachyose.

In the heydey of the opium trade, "chandoo" opium, which was meant to be smoked, was made by long term fermentation of "A. niger" and other molds on raw opium.cite journal |author=Calmette, L.C.A. |title=La fermentation de l'opium des fumeurs |journal=Arch. méd. navale coloniale|volume=57 |pages=132–138 |year=1892]

"A. niger" is the main agent in the fermentation of Pu-erh tea. [Citation
last = Petro
first = Mike
author-link =
title = Pu-erh, A Westerner's Quest
date =
year =
url = http://www.pu-erh.net/sections.php?Choice=Green_Puerh
accessdate = 2008-07-10]

Genetics

The genomes of two different "A. niger" strains have been fully sequenced.cite journal |author=Pel H, de Winde J, Archer D, "et al" |title=Genome sequencing and analysis of the versatile cell factory Aspergillus niger CBS 513.88 |journal=Nat Biotechnol |volume=25 |issue=2 |pages=221–31 |year=2007 |pmid=17259976 |doi=10.1038/nbt1282]

ee also

*Contamination control

References

External links

* [http://www.aspergillus.man.ac.uk/ "Aspergillus" website (Manchester University, UK)]
* [http://www.cdc.gov/ncidod/dbmd/diseaseinfo/aspergillosis_t.htm "Aspergillosis" information (Center for Disease Control)]
* [http://www.inchem.org/documents/jecfa/jecmono/v06je31.htm World Health Organisation report on "Aspergillus niger"]