Aspergillus niger

Micrograph (100 × magnification)

The Black watering can mold or short black mold ( Aspergillus niger) is a mold of the family Trichocomaceae. His Vernakularname derives from the dark, almost black spores.

Occurrence

The Black watering can mold occurs worldwide in the soil and is a common mold on spoiled food in the household. In nature, the fungus infects different fruit and vegetables such as grapes, onions or peanuts, but also in the form of stains on walls or plaster ( flat gray film on walls but is usually attributed to other causes, see black dust).

Metabolites

Through metabolic products of the fungus many organic materials can be damaged, but also the surface of glass lenses are clouded by optical devices (see also glass mushroom). Aspergillus niger forms various mycotoxins, such as kojic acid and ochratoxin. The genus Aspergillus can be the cause for a number of health problems.

The fungus used in the food industry for the production of citric acid. He distinguishes this from acid at low pH values ​​and under iron deficiency because of the citric acid cycle is disturbed. In life and feed the black watering can mold is used to produce various enzymes. Under controlled growth conditions, Aspergillus niger produces a wide range of specific and non-specific cellulases, hemicellulases, glucanases, phytases and proteases. These are used for a natural alternative to enzymes derived from genetically modified microorganisms offer.

Environment

Most preferably, the fungal growth at 35 to 37 ° C, but the temperature may be 6-47 ° C, without that it has problems in terms of growth. The spores do not survive damp cold at -22 ° C. The fungus tolerated pH range from 1.5 to 9,8 is thus able to exist in strongly acidic and in basic medium.