Aspergillus is a genus consisting of about two hundred fungal species found throughout the world. It is a filamentous fungus commonly found naturally in soils, hay and compost. The species are widespread and play an important role in soil ecology.
Aspergillus was first described in 1729 by Italian biologist Pietro Antonio Micheli in his book Nova plantarum genera juxta Tournefortii methodum disposita. Studying the fungus, its shape reminded him of an aspergillum (holy water brush), used for sprinkling with holy water.
Aspergillus is a widely used model organism in the sciences and has a number of important biotechnological applications. The species A. niger is used industrially worldwide for the production of various enzymes, organic acids and secondary metabolites. Some species can cause severe fungal infections in humans.
Growth and spread
Aspergillus species are highly aerobic and are found in almost all oxygen-rich environments, where they usually grow on the surface of the substrate. Aspergillus species can use polysaccharides as carbon sources because they possess amylase enzymes. As a result, Aspergillus species often occur as contaminants on starchy foods, such as bread and potatoes, and on many herbaceous plant and tree species.
Many species can live in nutrient-poor (oligotrophic) environments. Aspergillus niger is a good example of this. This fungus can grow on damp walls and even under conditions where no carbon is present at all. The fungus then uses the salts and nitrogen sources present, such as ammonia and nitrate for growth and protein production.
The reproduction of Aspergillus has been thoroughly studied. All species form a characteristic spore-bearing structure (ascus) during their asexual reproduction. The spores can spread through the air over long distances. When a spore comes in contact with a moist substrate, it can germinate under the right conditions. About a third of the species have also developed a mode of sexual reproduction. Sexually reproducing species produce special fungal filaments for self-fertilization (homothallia).
Aspergillus species are by far the most important commercial fungi and are used to produce both primary and secondary metabolites. Perhaps best known is the production of citric acid by Aspergillus niger. More than 4.5 million tons of citric acid are produced annually by this fungus. In addition, the fungus is used to produce enzymes, such as glucose oxidase and the protein-splitting lysozyme. Enzyme production takes place mainly in bioreactors. In these, the fungus is in an aqueous environment, so the fungus grows very rapidly, produces and excretes many proteins, and it is easier to separate the excreted products from the medium.
Various Penicillium, Aspergillus spp. (and some other fungi) growing on a nutrient media
Several Aspergillus species, such as A. nidulans and A. niger, have been used for many years as model organisms in microbiology and biotechnology. For example, Italian geneticist Guido Pontecorvo used the fungus to demonstrate parasexuality in fungi. Aspergillus nidulans was one of the first organisms used by researchers at the Broad Institute for nucleotide sequencing (DNA sequencing). Since then, the base pair sequence of many Aspergillus species has been determined.
Some Aspergillus species cause serious diseases in humans and animals. These diseases are known by the collective name Aspergillosis. The best known species are Aspergillus fumigatus, Aspergillus flavus and Aspergillus clavatus. Other species are pathogens of cereals, especially corn, or cause storage rot in sugar beets. Several species produce mycotoxins, such as aflatoxin produced by Aspergillus flavus and Aspergillus parasiticus, ochratoxin produced by Aspergillus ochraceus and Aspergillus carbonarius or sterigmatocystin produced by Aspergillus versicolor....
- Aspergillus caesiellus
- Aspergillus candidus
- Aspergillus carbonarius
- Aspergillus carneus
- Aspergillus clavatus
- Aspergillus deflectus
- Aspergillus flavus
- Aspergillus fumigatus
- Aspergillus glaucus
- Aspergillus nidulans
- Aspergillus niger
- Aspergillus ochraceus
- Aspergillus oryzae
- Aspergillus parasiticus
- Aspergillus penicilloides
- Aspergillus restrictus
- Aspergillus sojae
- Aspergillus sydowi
- Aspergillus terreus
- Aspergillus ustus
- Aspergillus versicolor
BeterKliniek is the clinic for Integrative Medicine that bridges regular and non-regular medicine.
An van Veen (physician) and Michael van Gils (therapist) look for the cause of a condition or disease. That is where the treatment starts otherwise, as people often say, it is 'carrying water to the sea'. We call this cause medicine. Sometimes it is also desirable to treat the symptoms (at the same time). We call this symptom medicine.
Chronic disorders often have their cause in epi- genetics. You can schedule a free informative telephone consultation (phone number 040-7117337 until 1 p.m.) at BeterKliniek to discuss your symptoms so that we can provide you with further advice.