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Penicillium Pengo.jpg
Penicillium sp.
Scientific classification Red Pencil Icon.png
Kingdom: Fungi
Division: Ascomycota
Class: Eurotiomycetes
Order: Eurotiales
Family: Trichocomaceae
Genus: Penicillium
Link (1809)
Type species
Penicillium expansum
Link (1809)

over 300
List of Penicillium species

Synonyms [1]

Floccaria Grev. (1827)
Aspergilloides Dierckx (1901)
Walzia Sorokin (1871)
Pritzeliella Henn. (1903)


Penicillium ( /ˌpɛnɪˈsɪliəm/ ) is a genus of ascomycetous fungi that is part of the mycobiome of many species and is of major importance in the natural environment, in food spoilage, and in food and drug production.

Some members of the genus produce penicillin, a molecule that is used as an antibiotic, which kills or stops the growth of certain kinds of bacteria. Other species are used in cheesemaking. According to the Dictionary of the Fungi (10th edition, 2008), the widespread genus contains over 300 species. [2]


The genus was first described in the scientific literature by Johann Heinrich Friedrich Link in his 1809 work Observationes in ordines plantarum naturales; he wrote, "Penicillium. Thallus e floccis caespitosis septatis simplicibus aut ramosis fertilibus erectis apice penicillatis", where penicillatis means "having tufts of fine hair". [3] [4] Link included three species— P. candidum , P. expansum , and P. glaucum —all of which produced a brush-like conidiophore (asexual spore-producing structure). The common apple rot fungus P. expansum was later selected as the type species. [5]

In his 1979 monograph, John I. Pitt divided Penicillium into four subgenera based on conidiophore morphology and branching pattern: Aspergilloides, Biverticillium, Furcatum, and Penicillium. [6] Species included in subgenus Biverticillium were later merged into Talaromyces .


Various fungi including Penicillium and Aspergillus species growing in axenic culture Ascomycetes.jpg
Various fungi including Penicillium and Aspergillus species growing in axenic culture
Some penicillium mold on mandarin oranges, probably Penicillium digitatum. Penicilliummandarijntjes.jpg
Some penicillium mold on mandarin oranges, probably Penicillium digitatum.

Selected species include;


The genus name is derived from the Latin root penicillum, meaning "painter's brush", and refers to the chains of conidia that resemble a broom. [7]


Penicillium sp. under bright field microscopy (10 x 100 magnification) with lactophenol cotton blue stain Penicillium Spp..jpg
Penicillium sp. under bright field microscopy (10 × 100 magnification) with lactophenol cotton blue stain

The thallus (mycelium) consists of highly branched networks of multinucleated, usually colourless hyphae, with each pair of cells separated by a septum. Conidiophores are at the end of each branch accompanied by green spherical constricted units called conidia. These propagules play a significant role in reproduction; conidia are the main dispersal strategy of these fungi. [8]

Sexual reproduction involves the production of ascospores, commencing with the fusion of an archegonium and an antheridium, with sharing of nuclei. The irregularly distributed asci contain eight unicellular ascospores each.


Species of Penicillium are ubiquitous soil fungi preferring cool and moderate climates, commonly present wherever organic material is available. Saprophytic species of Penicillium and Aspergillus are among the best-known representatives of the Eurotiales and live mainly on organic biodegradable substances. Commonly known in America as molds, they are among the main causes of food spoilage, especially species of subgenus Penicillium. [9] Many species produce highly toxic mycotoxins. The ability of these Penicillium species to grow on seeds and other stored foods depends on their propensity to thrive in low humidity and to colonize rapidly by aerial dispersion while the seeds are sufficiently moist. [10] Some species have a blue color, commonly growing on old bread and giving it a blue fuzzy texture.

Some Penicillium species affect the fruits and bulbs of plants, including P. expansum , apples and pears; P. digitatum , citrus fruits; [11] and P. allii , garlic. [12] Some species are known to be pathogenic to animals; P. corylophilum , P. fellutanum , P. implicatum , P. janthinellum , P. viridicatum , and P. waksmanii are potential pathogens of mosquitoes. [13]

Penicillium species are present in the air and dust of indoor environments, such as homes and public buildings. The fungus can be readily transported from the outdoors, and grow indoors using building material or accumulated soil to obtain nutrients for growth. Penicillium growth can still occur indoors even if the relative humidity is low, as long as there is sufficient moisture available on a given surface. A British study determined that Aspergillus- and Penicillium-type spores were the most prevalent in the indoor air of residential properties, and exceeded outdoor levels. [14] Even ceiling tiles can support the growth of Penicillium—as one study demonstrated—if the relative humidity is 85% and the moisture content of the tiles is greater than 2.2%. [15]

Some Penicillium species cause damage to machinery and the combustible materials and lubricants used to run and maintain them. For example, P. chrysogenum (formerly P. notatum), P. steckii ,   P. cyclopium , and P. nalgiovensis affect fuels; P. chrysogenum, P. rubrum , and P. verrucosum cause damage to oils and lubricants; P. regulosum damages optical and protective glass. [16]

Economic value

Penicillin core.svg
Core structure of penicillin

Several species of the genus Penicillium play a central role in the production of cheese and of various meat products. To be specific, Penicillium molds are found in Blue cheese. Penicillium camemberti and Penicillium roqueforti are the molds on Camembert, Brie, Roquefort, and many other cheeses. Penicillium nalgiovense is used in soft mold-ripened cheeses, such as Nalžovy (ellischau) cheese, and to improve the taste of sausages and hams, and to prevent colonization by other molds and bacteria. [17] [18]

In addition to their importance in the food industry, species of Penicillium and Aspergillus serve in the production of a number of biotechnologically produced enzymes and other macromolecules, such as gluconic, citric, and tartaric acids, as well as several pectinases, lipase, amylases, cellulases, and proteases. Some Penicillium species have shown potential for use in bioremediation, more specifically mycoremediation, because of their ability to break down a variety of xenobiotic compounds. [19]

The genus includes a wide variety of species molds that are the source molds of major antibiotics. Penicillin, a drug produced by P. chrysogenum (formerly P. notatum), was accidentally discovered by Alexander Fleming in 1929, and found to inhibit the growth of Gram-positive bacteria (see beta-lactams). Its potential as an antibiotic was realized in the late 1930s, and Howard Florey and Ernst Chain purified and concentrated the compound. The drug's success in saving soldiers in World War II who had been dying from infected wounds resulted in Fleming, Florey and Chain jointly winning the Nobel Prize in Medicine in 1945. [20]

Griseofulvin is an antifungal drug and a potential chemotherapeutic agent [21] that was discovered in P. griseofulvum . [22] Additional species that produce compounds capable of inhibiting the growth of tumor cells in vitro include: P. pinophilum , [23] P. canescens , [24] and P. glabrum . [24]


Although many eukaryotes are able to reproduce sexually, as much as 20% of fungal species had been thought to reproduce exclusively by asexual means. However recent studies have revealed that sex occurs even in some of the supposedly asexual species. For example, sexual capability was recently shown for the fungus Penicillium roqueforti , used as a starter for blue cheese production. [25] This finding was based, in part, on evidence for functional mating type (MAT) genes that are involved in fungal sexual compatibility, and the presence in the sequenced genome of most of the important genes known to be involved in meiosis. Penicillium chrysogenum is of major medical and historical importance as the original and present-day industrial source of the antibiotic penicillin. The species was considered asexual for more than 100 years despite concerted efforts to induce sexual reproduction. However, in 2013, Bohm et al. [26] finally demonstrated sexual reproduction in P. chrysogenum.

These findings with Penicillium species are consistent with accumulating evidence from studies of other eukaryotic species that sex was likely present in the common ancestor of all eukaryotes. [27] Furthermore, these recent results suggest that sex can be maintained even when very little genetic variability is produced.

Prior to 2013, when the "one fungus, one name" nomenclature change came into effect, Penicillium was used as the genus for anamorph (clonal forms) of fungi and Talaromyces was used for the teleomorph (sexual forms) of fungi. After 2013 however, fungi were reclassified based on their genetic relatedness to each other and now the genera Penicillium and Talaromyces both contain some species capable of only clonal reproduction and others that can reproduce sexually.

Related Research Articles

<span class="mw-page-title-main">Ascomycota</span> Division or phylum of fungi

Ascomycota is a phylum of the kingdom Fungi that, together with the Basidiomycota, forms the subkingdom Dikarya. Its members are commonly known as the sac fungi or ascomycetes. It is the largest phylum of Fungi, with over 64,000 species. The defining feature of this fungal group is the "ascus", a microscopic sexual structure in which nonmotile spores, called ascospores, are formed. However, some species of the Ascomycota are asexual, meaning that they do not have a sexual cycle and thus do not form asci or ascospores. Familiar examples of sac fungi include morels, truffles, brewers' and bakers' yeast, dead man's fingers, and cup fungi. The fungal symbionts in the majority of lichens such as Cladonia belong to the Ascomycota.

<span class="mw-page-title-main">Mold</span> Wooly, dust-like fungal structure or substance

A mold or mould is one of the structures certain fungi can form. The dust-like, colored appearance of molds is due to the formation of spores containing fungal secondary metabolites. The spores are the dispersal units of the fungi. Not all fungi form molds. Some fungi form mushrooms; others grow as single cells and are called microfungi.

<i>Talaromyces marneffei</i> Species of fungus

Talaromyces marneffei, formerly called Penicillium marneffei, was identified in 1956. The organism is endemic to southeast Asia where it is an important cause of opportunistic infections in those with HIV/AIDS-related immunodeficiency. Incidence of T. marneffei infections has increased due to a rise in HIV infection rates in the region.

<span class="mw-page-title-main">Eurotiales</span> Order of fungi

The Eurotiales are an order of sac fungi, also known as the green and blue molds. It was circumscribed in 1980.

<i>Aspergillus</i> Genus of fungi

Aspergillus is a genus consisting of several hundred mold species found in various climates worldwide.

<i>Penicillium roqueforti</i> Species of fungus

Penicillium roqueforti is a common saprotrophic fungus in the genus Penicillium. Widespread in nature, it can be isolated from soil, decaying organic matter, and plants.

<i>Penicillium camemberti</i> Species of fungus

Penicillium camemberti is a species of fungus in the genus Penicillium. It is used in the production of Camembert, Brie, Langres, Coulommiers, and Cambozola cheeses, on which colonies of P. camemberti form a hard, white crust. It is responsible for giving these cheeses their distinctive flavors. An allergy to the antibiotic penicillin does not necessarily imply an allergy to cheeses made using P. camemberti.

<span class="mw-page-title-main">History of penicillin</span>

The history of penicillin follows a number of observations and discoveries of apparent evidence of antibiotic activity of the mould Penicillium that led to the development of penicillins that became the most widely used antibiotics. Following the identification of Penicillium rubens as the source of the compound in 1928 and with the production of pure compound in 1942, penicillin became the first naturally derived antibiotic. There are anecdotes about ancient societies using moulds to treat infections, and in the following centuries many people observed the inhibition of bacterial growth by various moulds. However, it is unknown if the species involved were Penicillium species or if the antimicrobial substances produced were penicillin.

<i>Penicillium expansum</i> Species of fungus

Penicillium expansum is a psychrophilic blue mold that is common throughout the world in soil. It causes Blue Mold of apples, one of the most prevalent and economically damaging post-harvest diseases of apples.

The parasexual cycle, a process restricted to fungi and single-celled organisms, is a nonsexual mechanism of parasexuality for transferring genetic material without meiosis or the development of sexual structures. It was first described by Italian geneticist Guido Pontecorvo in 1956 during studies on Aspergillus nidulans. A parasexual cycle is initiated by the fusion of hyphae (anastomosis) during which nuclei and other cytoplasmic components occupy the same cell. Fusion of the unlike nuclei in the cell of the heterokaryon results in formation of a diploid nucleus (karyogamy), which is believed to be unstable and can produce segregants by recombination involving mitotic crossing-over and haploidization. Mitotic crossing-over can lead to the exchange of genes on chromosomes; while haploidization probably involves mitotic nondisjunctions which randomly reassort the chromosomes and result in the production of aneuploid and haploid cells. Like a sexual cycle, parasexuality gives the species the opportunity to recombine the genome and produce new genotypes in their offspring. Unlike a sexual cycle, the process lacks coordination and is exclusively mitotic.

<span class="mw-page-title-main">Fungus</span> Biological kingdom, separate from plants and animals

A fungus is any member of the group of eukaryotic organisms that includes microorganisms such as yeasts and molds, as well as the more familiar mushrooms. These organisms are classified as a kingdom, separately from the other eukaryotic kingdoms, which by one traditional classification include Plantae, Animalia, Protozoa, and Chromista.

<i>Penicillium chrysogenum</i> Species of fungus

Penicillium chrysogenum is a species of fungus in the genus Penicillium. It is common in temperate and subtropical regions and can be found on salted food products, but it is mostly found in indoor environments, especially in damp or water-damaged buildings. It has been recognised as a species complex that includes P. notatum, P. meleagrinum, and P. cyaneofulvum, but molecular phylogeny established that it is a distinct species and that P. notatum is P. rubens. It has rarely been reported as a cause of human disease. It is the source of several β-lactam antibiotics, most significantly penicillin. Other secondary metabolites of P. chrysogenum include roquefortine C, meleagrin, chrysogine, 6-MSA YWA1/melanin, andrastatin A, fungisporin, secalonic acids, sorbicillin, and PR-toxin.

<span class="mw-page-title-main">Fungi imperfecti</span> Fungal classification based on asexual characters when sexual reproduction is unidentified

The fungi imperfecti or imperfect fungi, are fungi which do not fit into the commonly established taxonomic classifications of fungi that are based on biological species concepts or morphological characteristics of sexual structures because their sexual form of reproduction has never been observed. They are known as imperfect fungi because only their asexual and vegetative phases are known. They have asexual form of reproduction, meaning that these fungi produce their spores asexually, in the process called sporogenesis.

<span class="mw-page-title-main">Charles Thom</span> American icrobiologist and mycologist

Charles Thom was an American microbiologist and mycologist. Born and raised in Illinois, he received his PhD from the University of Missouri, the first such degree awarded by that institution. He was best known for his work on the microbiology of dairy products and soil fungi, and in particular his research into the genera Aspergillus and Penicillium. His work influenced the establishment of standards for food handling and processing in the USA. He pioneered the use of culture media to grow microorganisms, and, with food chemist James N. Currie, developed a process to mass-produce citric acid using Aspergillus. Thom played an important role in the development of penicillin in World War II.

<i>Penicillium rubens</i> Species of fungus

Penicillium rubens is a species of fungus in the genus Penicillium and was the first species known to produce the antibiotic penicillin. It was first described by Philibert Melchior Joseph Ehi Biourge in 1923. For the discovery of penicillin from this species Alexander Fleming shared the Nobel Prize in Physiology or Medicine in 1945. The original penicillin-producing type has been variously identified as Penicillium rubrum, P. notatum, and P. chrysogenum among others, but genomic comparison and phylogenetic analysis in 2011 resolved that it is P. rubens. It is the best source of penicillins and produces benzylpenicillin (G), phenoxymethylpenicillin (V) and octanoylpenicillin (K). It also produces other important bioactive compounds such as andrastin, chrysogine, fungisporin, roquefortine, and sorbicillins.

Penicillium carneum is a fungus species of the genus of Penicillium.Penicillium roqueforti var. carneum was reclassified to Penicillium carneum.P. carneum was isolated from spoiled meat products, silage, rye bread, water, beer, cheese, mouldy barkers yeast and cork. P. carneum produces patulin, penicillic acid, penitrem A, mycophenolic acid roquefortines.

Penicillium psychrosexualis is a filamentous fungus in the genus Penicillium. Described as new to science in 2010, the species was found growing on refrigerated moldy apples in the Netherlands. It is closely related to the blue cheese fungus P. roqueforti.

Fungi – "Fungi" is plural for "fungus". A fungus is any member of the group of eukaryotic organisms that includes unicellular microorganisms such as yeasts and molds, as well as multicellular fungi that produce familiar fruiting forms known as mushrooms. Biologists classify these organisms as a kingdom, Fungi, the second highest taxonomic rank of living organism beneath the Eukaryota domain; other kingdoms include plants, animals, protists, and bacteria. One difference that places fungi in a different kingdom is that their cell walls contain chitin, unlike the cell walls of plants, bacteria and some protists. Similar to animals, fungi are heterotrophs, that is, they acquire their food by absorbing dissolved molecules, typically by secreting digestive enzymes into their environment. Growth is their means of mobility, except for spores, which may travel through air or water. Fungi function as the principal decomposers in ecological systems.

Penicillium commune is an indoor fungus belonging to the genus Penicillium. It is known as one of the most common fungi spoilage moulds on cheese. It also grows on and spoils other foods such as meat products and fat-containing products like nuts and margarine. Cyclopiazonic acid and regulovasine A and B are the most important mycotoxins produced by P. commune. The fungus is the only known species to be able to produce both penitrem A and roquefortine. Although this species does not produce penicillin, it has shown to have anti-pathogenic activity. There are no known plant, animal or human diseases caused by P. commune.

Aspergillus giganteus is a species of fungus in the genus Aspergillus that grows as a mold. It was first described in 1901 by Wehmer, and is one of six Aspergillus species from the Clavati section of the subgenus Fumigati. Its closest taxonomic relatives are Aspergillus rhizopodus and Aspergillus longivescia.


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