''Monascus purpureus'' (syn. ''M. albidus'', ''M. anka'', ''M. araneosus'', ''M. major'', ''M. rubiginosus'', and ''M. vini''; , lit. "red yeast") is a species of

mold 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 ...

that is purplish-red in color. It is also known by the names ang-khak rice mold, corn silage mold, maize silage mold, and rice kernel discoloration.

Taxonomy and morphology

The sexual state of ''M. purpureus'' is a cleistothecium with a two-layered wall enclosing round, evanescent 8-spored asci, lifted above the substrate on a multihyphal stalk. Ascospores can be heat resistant. The asexual state forms chains of hyaline or brownish

chlamydospore A chlamydospore is the thick-walled large resting spore of several kinds of fungi, including Ascomycota such as '' Candida'', Basidiomycota such as '' Panus'', and various Mortierellales species. It is the life-stage which survives in unfavourable ...

-like cells.

Physiology and metabolites

During growth, ''Monascus'' spp. break down starch substrate into several metabolites, including

pigment A pigment is a colored material that is completely or nearly insoluble in water. In contrast, dyes are typically soluble, at least at some stage in their use. Generally dyes are often organic compounds whereas pigments are often inorganic compou ...

s produced as secondary metabolites. The structure of pigments depends on type of substrate and other specific factors during culture, such as pH, temperature, and moisture content. However, discoveries of cholesterol-lowering

statin Statins, also known as HMG-CoA reductase inhibitors, are a class of lipid-lowering medications that reduce illness and mortality in those who are at high risk of cardiovascular disease. They are the most common cholesterol-lowering drugs. Low ...

s produced by the mold has prompted research into its possible medical uses. It produces a number of statins. The naturally occurring lovastatins and analogs are called monacolins K, L, J, and also occur in their hydroxyl acid forms along with dehydroxymonacolin and compactin (

mevastatin Mevastatin (compactin, ML-236B) is a hypolipidemic agent that belongs to the statins class. It was isolated from the mold ''Penicillium citrinum'' by Akira Endo in the 1970s, and he identified it as a HMG-CoA reductase inhibitor, i.e., a statin. ...

). The prescription drug

lovastatin Lovastatin, sold under the brand name Mevacor among others, is a statin medication, to treat high blood cholesterol and reduce the risk of cardiovascular disease. Its use is recommended together with lifestyle changes. It is taken by mouth. ...

, identical to monacolin K, is the principal statin produced by ''M. purpureus''. Only the open-ring (hydroxy acid) form is pharmacologically active, but it is not produced on a commercial scale. The

mycotoxin A mycotoxin (from the Greek μύκης , "fungus" and τοξίνη , "toxin") is a toxic secondary metabolite produced by organisms of kingdom Fungi and is capable of causing disease and death in both humans and other animals. The term 'mycotoxin' ...

citrinin Citrinin is a mycotoxin which is often found in food. It is a secondary metabolite produced by fungi that contaminates long-stored food and it causes different toxic effects, like nephrotoxic, hepatotoxic and cytotoxic effects. Citrinin is mainly ...

is carefully monitored when ''Monascus'' is used in fermented foods. Industrial use of soluble red pigments as food dyes was discontinued in the USA and Europe because of this risk.

Importance

''Monascus purpureus'' has been used for >1000 years in oriental fermented foods, including red kōji-kin, red yeast rice or ank-kak,

rice wine Rice wine is an alcoholic beverage fermented and distilled from rice, traditionally consumed in East Asia, Southeast Asia and South Asia. Rice wine is made by the fermentation of rice starch that has been converted to sugars. Microbes are the s ...

, kaoliang brandy, and as the coloring agent for

Peking duck Peking duck is a dish from Beijing (Peking) that has been prepared since the Imperial era. The meat is characterized by its thin, crispy skin, with authentic versions of the dish serving mostly the skin and little meat, sliced in front of the di ...

Commercial species

The related fungi ''M. ruber'' and ''M. pilosus'' are also used in industrial applications. ''Monascus ruber'' is also a common food spoilage organism; most strains produce a brown pigment.

References

*Bibhu Prasad Panda, Saleem Javed, Mohd. Ali (2010) Optimization of fermentation parameters for higher lovastatin production in red mold rice through co-culture of ''Monascus purpureus'' and ''Monascus ruber''. ''Food and Bioprocess Technology'', Vol. 3, no.3, 373-378

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