Penicillium roqueforti is a common saprotrophic fungus

Fungus

A fungus is a member of a large 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, Fungi, which is separate from plants, animals, and bacteria...

 from the family

Family (biology)

In biological classification, family is* a taxonomic rank. Other well-known ranks are life, domain, kingdom, phylum, class, order, genus, and species, with family fitting between order and genus. As for the other well-known ranks, there is the option of an immediately lower rank, indicated by the...

 Trichocomaceae

Trichocomaceae

Trichocomaceae is a family of the order Eurotiales. Taxa are saprobes with aggressive colonization strategies, adaptable to extreme environmental conditions. Family members are cosmopolitan in distribution, ubiquitous in soil and very common associates of decaying plant and food material. The...

. Widespread in nature, it can be isolated from soil, decaying organic matter, and plants. The major industrial use of this fungus is the production of blue cheese

Blue cheese

Blue cheese is a general classification of cow's milk, sheep's milk, or goat's milk cheeses that have had cultures of the mold Penicillium added so that the final product is spotted or veined throughout with blue, blue-gray or blue-green mold, and carries a distinct smell, either from that or...

s, flavouring agents, antifungals, polysaccharide

Polysaccharide

Polysaccharides are long carbohydrate molecules, of repeated monomer units joined together by glycosidic bonds. They range in structure from linear to highly branched. Polysaccharides are often quite heterogeneous, containing slight modifications of the repeating unit. Depending on the structure,...

s, protease

Protease

A protease is any enzyme that conducts proteolysis, that is, begins protein catabolism by hydrolysis of the peptide bonds that link amino acids together in the polypeptide chain forming the protein....

s and other enzyme

Enzyme

Enzymes are proteins that catalyze chemical reactions. In enzymatic reactions, the molecules at the beginning of the process, called substrates, are converted into different molecules, called products. Almost all chemical reactions in a biological cell need enzymes in order to occur at rates...

s. The fungus has been a constituent of Roquefort

Roquefort (cheese)

Roquefort , sometimes spelled Rochefort in English, is a sheep milk blue cheese from the south of France, and together with Bleu d'Auvergne, Stilton and Gorgonzola is one of the world's best-known blue cheeses...

, Stilton

Stilton (cheese)

Stilton is a type of English cheese, known for its characteristic strong smell and taste. It is produced in two varieties: the well-known blue and the lesser-known white. Both have been granted the status of a protected designation of origin by the European Commission, together one of only...

, Danish blue, Cabrales

Cabrales cheese

Cabrales is a cheese made in the artisan tradition by rural dairy farmers in the north of Spain. This cheese can be made from pure, unpasteurised cow’s milk or blended in the traditional manner with goat and/or sheep milk, which lends the cheese a stronger, more spicy flavor.All of the milk used...

 and other blue cheeses eaten by humans since about 50 AD; blue cheese is mentioned in literature as far back as AD 79, when Pliny the Elder

Pliny the Elder

Gaius Plinius Secundus , better known as Pliny the Elder, was a Roman author, naturalist, and natural philosopher, as well as naval and army commander of the early Roman Empire, and personal friend of the emperor Vespasian...

 remarked upon its rich flavour.

Classification

First described by Thom in 1906, P. roqueforti was initially a heterogeneous species of blue-green sporulating fungi. They were grouped into different species based on phenotypic

Phenotype

A phenotype is an organism's observable characteristics or traits: such as its morphology, development, biochemical or physiological properties, behavior, and products of behavior...

 differences, but later combined into one species by Raper and Thom (1949). The P. roqueforti group got a reclassification in 1996 thanks to molecular analysis of ribosomal DNA

Ribosomal DNA

Ribosomal DNA codes for ribosomal RNA. The ribosome is an intracellular macromolecule that produces proteins or polypeptide chains. The ribosome itself consists of a composite of proteins and RNA. As shown in the figure, rDNA consists of a tandem repeat of a unit segment, an operon, composed of...

 sequences. Formerly divided into two varieties ― cheese-making (P. roqueforti var. roqueforti) and patulin

Patulin

Patulin is a mycotoxin produced by a variety of molds, in particular, Aspergillus and Penicillium. It is commonly found in rotting apples, and the amount of patulin in apple products is generally viewed as a measure of the quality of the apples used in production...

-making (P. roqueforti var. carneum), P. roqueforti was reclassified into three species named P. roqueforti, P. carneum and P. paneum.

Description

As this fungus does not form visible fruiting bodies, descriptions are based on macromorphological characteristics of fungal colonies growing on various standard agar media, and on microscopic characteristics. When grown on Czapek yeast autolysate (CYA) agar or yeast-extract sucrose (YES) agar, P. roqueforti colonies are typically 40 mm in diameter, olive brown to dull green (dark green to black on the reverse side of the agar plate), with a velutinous texture. Grown on malt extract (MEA) agar, colonies are 50 mm in diameter, dull green in color (beige to greyish green on the reverse side), with arachnoid (with many spider-web-like fibers) colony margins. Another characteristic morphological feature of this species includes the production of asexual spores in phialides with a distinctive brush-shaped configuration.

P. roqueforti is known to be one of the most common spoilage molds of silage

Silage

Silage is fermented, high-moisture fodder that can be fed to ruminants or used as a biofuel feedstock for anaerobic digesters. It is fermented and stored in a process called ensiling or silaging, and is usually made from grass crops, including corn , sorghum or other cereals, using the entire...

. It is also one of several different molds that can spoil bread.

Uses

The chief industrial use of this species is the production of blue cheeses, such as its namesake Roquefort, Bleu de Bresse

Bleu de Bresse

Bleu de Bresse is a blue cheese that was first made in the Bresse area of France following World War II. Made from whole milk, it has a firm, edible coating which is characteristically white in color and has an aroma of mushrooms. Its creamy interior, similar in texture to Brie, contains patches...

, Bleu du Vercors-Sassenage

Bleu du Vercors-Sassenage

Bleu du Vercors-Sassenage is a mild pasteurized natural rind cow's milk blue cheese originally produced by monks in the Rhône-Alpes region of France in the 14th century. Now made in the Dauphiné area, the cheese has been a protected Appellation d'Origine Contrôlée since 1998. As a requirement, the...

, Brebiblu, Cabrales

Cabrales cheese

Cabrales is a cheese made in the artisan tradition by rural dairy farmers in the north of Spain. This cheese can be made from pure, unpasteurised cow’s milk or blended in the traditional manner with goat and/or sheep milk, which lends the cheese a stronger, more spicy flavor.All of the milk used...

, Cambozola

Cambozola

Cambozola is a cow's milk cheese that is a combination of a French soft-ripened triple cream cheese and Italian Gorgonzola.-History:It was patented and industrially produced for the world market by large German company Champignon in the 1970s. The cheese was invented circa 1900 and is still...

 (Blue Brie), Cashel Blue, Danish blue, Fourme d'Ambert

Fourme d'Ambert

Fourme d'Ambert is one of France's oldest cheeses, and dates from as far back as Roman times. It is a usually pasteurized cow's milk blue cheese from the Auvergne region of France, with a distinct, narrow cylindrical shape....

, Fourme de Montbrison

Fourme de Montbrison

Fourme de Montbrison is a cow's-milk cheese made in the regions of Rhône-Alpes and Auvergne in southern France. It derives its name from the town of Montbrison in the Loire department....

, Lanark Blue

Lanark Blue

Lanark Blue is a sheep milk cheese produced in Lanarkshire, Scotland.Produced at Ogcastle near to the village of Carnwath by Humphrey Errington since 1985, it is a rich blue-veined artisan cheese...

, Shropshire Blue and Stilton, and some varieties of Bleu d'Auvergne

Bleu d'Auvergne

Bleu d'Auvergne is a French blue cheese, named for its place of origin in the Auvergne region of south-central France. It is made from cow's milk, and is one of the cheeses granted the Appellation d'Origine Contrôlée from the French government....

 and Gorgonzola. (Other blue cheeses, including Bleu de Gex

Bleu de Gex

Bleu de Gex is a creamy, semi-soft blue cheese made from unpasteurized milk in the Jura region of France. During production, Penicillium glaucum mold is introduced and the unwashed curds are loosely packed. It is then aged for at least three weeks...

 and Rochebaron use Penicillium glaucum

Penicillium glaucum

Penicillium glaucum is a mold which is used in the making of some types of blue cheese, including Bleu de Gex, Rochebaron and some varieties of Bleu d'Auvergne and Gorgonzola...

.)

Strains of the microorganism are also used to produce compounds that can be employed as antibiotic

Antibiotic

An antibacterial is a compound or substance that kills or slows down the growth of bacteria.The term is often used synonymously with the term antibiotic; today, however, with increased knowledge of the causative agents of various infectious diseases, antibiotic has come to denote a broader range of...

s, flavours, and fragrances (Sharpell, 1985), uses not regulated under the U.S. Toxic Substances Control Act

Toxic Substances Control Act

The Toxic Substances Control Act is a United States law, passed by the United States Congress in 1976, that regulates the introduction of new or already existing chemicals. It grandfathered most existing chemicals, in contrast to the Registration, Evaluation and Authorization of Chemicals ...

 (TSCA). Its texture is chitinous.

Secondary metabolites

Considerable evidence indicates that most strains are capable of producing harmful secondary metabolites (alkaloid

Alkaloid

Alkaloids are a group of naturally occurring chemical compounds that contain mostly basic nitrogen atoms. This group also includes some related compounds with neutral and even weakly acidic properties. Also some synthetic compounds of similar structure are attributed to alkaloids...

s and other mycotoxin

Mycotoxin

A mycotoxin is a toxic secondary metabolite produced by organisms of the fungus kingdom, commonly known as molds. The term ‘mycotoxin’ is usually reserved for the toxic chemical products produced by fungi that readily colonize crops...

s) under certain growth conditions.
Aristolochene

Aristolochene

Aristolochene is a bicyclic sesquiterpene produced by certain fungi including the cheese mold Penicillium roqueforti. It is biosynthesized from farnesyl pyrophosphate by aristolochene synthase and is the parent hydrocarbon of a large variety of fungal toxins.-External links:* at ChEBI...

 is a sesquiterpenoid compound produced by P. roqueforti, and is likely a precursor to the toxin known as PR toxin, made in large amounts by the fungus. PR-toxin has been implicated in incidents of mycotoxicoses resulting from eating contaminated grains. However, PR toxin is not stable in cheese and breaks down to the less toxic PR imine

Imine

An imine is a functional group or chemical compound containing a carbon–nitrogen double bond, with the nitrogen attached to a hydrogen atom or an organic group. If this group is not a hydrogen atom, then the compound is known as a Schiff base...

.

Secondary metabolite

Secondary metabolite

Secondary metabolites are organic compounds that are not directly involved in the normal growth, development, or reproduction of an organism. Unlike primary metabolites, absence of secondary metabolities does not result in immediate death, but rather in long-term impairment of the organism's...

s of P. roqueforti, named andrastins A-D, are found in blue cheese. The andrastins inhibit proteins involved in the efflux of anticancer drugs from multidrug-resistant cancer cell

Cancer cell

Cancer cells are cells that grow and divide at an unregulated, quickened pace. Although cancer cells can be quite common in a person they are only malignant when the other cells fail to recognize and/or destroy them. In the past a common belief was that cancer cells failed to be recognized and...

s.

The organism can also be used for the production of protease

Protease

A protease is any enzyme that conducts proteolysis, that is, begins protein catabolism by hydrolysis of the peptide bonds that link amino acids together in the polypeptide chain forming the protein....

s and speciality chemicals, such as methyl ketone

Ketone

In organic chemistry, a ketone is an organic compound with the structure RCR', where R and R' can be a variety of atoms and groups of atoms. It features a carbonyl group bonded to two other carbon atoms. Many ketones are known and many are of great importance in industry and in biology...

s including 2-heptanone

2-Heptanone

2-Heptanone, or methyl n-amyl ketone, is a ketone with the molecular formula C7H14O. It is a colorless, water-white liquid with a banana-like, fruity odor....

. Other strains of Penicillium species are also useful in biodeterioration.