Penicillium roqueforti

Penicillium roqueforti
Blue Stilton cheese, showing the blue-green mold veins produced by Penicillin roqueforti.
Scientific classification
Kingdom:	Fungi
Division:	Ascomycota
Class:	Eurotiomycetes
Order:	Eurotiales
Family:	Trichocomaceae
Genus:	Penicillium
Species:	P. roqueforti Thom.
Binomial name
Penicillium roqueforti

Penicillium roqueforti is a common saprotrophic fungus from the family Trichocomaceae. 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 cheeses, flavouring agents, antifungals, polysaccharides, proteases and other enzymes. The fungus has been a constituent of Roquefort, Stilton, Danish blue 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 remarked upon its rich flavour.^[1]

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 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 sequences. Formerly divided into two varieties ― cheese-making (P. roqueforti var. roqueforti) and patulin-making (P. roqueforti var. carneum), P. roqueforti was reclassified into three species named P. roqueforti, P. carneum and P. paneum.^[2]

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.^[3] Another characteristic morphological feature of this species includes the production of asexual spores in phialides with a distinctive brush-shaped configuration.^[4][5][6]

P. roqueforti is known to be one of the most common spoilage molds of silage.^{[7][8][9][10][11]} 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^[12], Bleu de Bresse, Bleu du Vercors-Sassenage, Brebiblu, Cambozola (Blue Brie), Cashel Blue, Danish blue, Fourme d'Ambert, Fourme de Montbrison, Lanark Blue, Shropshire Blue and Stilton, and some varieties of Bleu d'Auvergne and Gorgonzola. (Other blue cheeses, including Bleu de Gex and Rochebaron use Penicillium glaucum.)

Strains of the microorganism are also used to produce compounds that can be employed as antibiotics, flavours, and fragrances (Sharpell, 1985), uses not regulated under the U.S. Toxic Substances Control Act (TSCA). Its texture is chitinous.

Secondary metabolites

Considerable evidence indicates that most strains are capable of producing harmful secondary metabolites (alkaloids and other mycotoxins) under certain growth conditions.^{[13][14][15][16]} Aristolochene 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.^[17] PR-toxin has been implicated in incidents of mycotoxicoses resulting from eating contaminated grains.^[18][15] However, PR toxin is not stable in cheese and breaks down to the less toxic PR imine.^[19]

Secondary metabolites 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 cells.^[20]

The organism can also be used for the production of proteases and speciality chemicals, such as methyl ketones including 2-heptanone.^[21] Other strains of Penicillium species are also useful in biodeterioration.^[22]

References

1. ^ "The Cheese Companion: The ... - Google Book Search". http://books.google.com/books?id=bV1RVgNe_5wC&pg=PA10&dq=%22pliny+the+elder%22+blue+cheese&ei=8c82Sb-DMpT4NY_rgOcJ. Retrieved 2008-12-03. 
2. ^ Boysen M, Skouboe P, Frisvad J, Rossen L. (1996). "Reclassification of the Penicillium roqueforti group into three species on the basis of molecular genetic and biochemical profiles". Microbiology (Reading, Engl.) 142 (3): 541–9. doi:10.1099/13500872-142-3-541. PMID 8868429. 
3. ^ O'brien M, Egan D, O'kiely P, Forristal PD, Doohan FM, Fuller HT (August 2008). "Morphological and molecular characterisation of Penicillium roqueforti and P. paneum isolated from baled grass silage". Mycol. Res. 112 (Pt 8): 921–32. doi:10.1016/j.mycres.2008.01.023. PMID 18554890. 
4. ^ Raper KB, Alexander DF, Coghill RD (December 1944). "Penicillin: II. Natural Variation and Penicillin Production in Penicillium notatum and Allied Species". J. Bacteriol. 48 (6): 639–59. PMC 374019. PMID 16560880. http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=374019. 
5. ^ Raper KB (1957). "Nomenclature in Aspergillus and Penicillium". Mycologia 49 (5): 644–662. doi:10.2307/3755984. JSTOR 3755984. 
6. ^ Samson RA, Gams W (1984). "The taxonomic situation in the hyphomycete genera Penicillium, Aspergillus and Fusarium". Antonie Van Leeuwenhoek 50 (5–6): 815–24. doi:10.1007/BF02386244. PMID 6397143. 
7. ^ Skaar I. (1996). Mycological survey and characterisation of the mycobiota of big bale grass silage in Norway. PhD thesis, Norwegian College of Veterinary Medicine, Oslo.
8. ^ Auerbach H, Oldenburg W, Weissbach F (2008). "Incidence of Penicillium roqueforti and roquefortine C in silages". Journal of the Science of Food and Agriculture 76 (4): 565–572. doi:10.1002/(SICI)1097-0010(199804)76:4<565::AID-JSFA990>3.0.CO;2-6. 
9. ^ Nielsen KF, M.W. Sumarah, Frisvad JC, Miller JD (2006). "Production of metabolites from the Penicillium roqueforti complex". Journal of Agricultural and Food Chemistry 54 (10): 3756–3763. doi:10.1021/jf060114f. PMID 19127756. 
10. ^ Mansfield MA, Kuldau GA (2007). "Microbiological and molecular determination of mycobiota in fresh and ensiled maize silage". Mycologia 99 (2): 269–78. doi:10.3852/mycologia.99.2.269. PMID 17682779. 
11. ^ Boysen ME, Jacobsson KG, Schnürer J (April 2000). "Molecular Identification of Species from the Penicillium roqueforti Group Associated with Spoiled Animal Feed". Appl. Environ. Microbiol. 66 (4): 1523–6. doi:10.1128/AEM.66.4.1523-1526.2000. PMC 92017. PMID 10742236. http://aem.asm.org/cgi/pmidlookup?view=long&pmid=10742236. 
12. ^ Kinsella JE, Hwang DH (November 1976). "Enzymes of Penicillium roqueforti involved in the biosynthesis of cheese flavour". CRC Crit Rev Food Sci Nutr 8 (2): 191–228. doi:10.1080/10408397609527222. PMID 21770. 
13. ^ Möller, T.; Åkerstrand, K.; Massoud, T. (1997). "Toxin-producing species ofPenicillium and the development of mycotoxins in must and homemade wine". Nat. Toxins 5 (2): 86–9. doi:10.1002/(SICI)(1997)5:2<86::AID-NT6>3.0.CO;2-7. PMID 9131595. 
14. ^ Finoli C, Vecchio A, Galli A, Dragoni I (February 2001). "Roquefortine C occurrence in blue cheese". J. Food Prot. 64 (2): 246–51. PMID 11271775. 
15. ^ ^{a b} Erdogan A, Sert S (March 2004). "Mycotoxin-forming ability of two Penicillium roqueforti strains in blue moldy tulum cheese ripened at various temperatures". J. Food Prot. 67 (3): 533–5. PMID 15035369. 
16. ^ O'Brien M, Nielsen KF, O'Kiely P, Forristal PD, Fuller HT, Frisvad JC (November 2006). "Mycotoxins and other secondary metabolites produced in vitro byPenicillium paneum Frisvad and Penicillium roqueforti Thom isolated from baled grass silage in Ireland". J. Agric. Food Chem. 54 (24): 9268–76. doi:10.1021/jf0621018. PMID 17117820. 
17. ^ Proctor RH, Hohn TM (February 1993). "Aristolochene synthase. Isolation, characterization, and bacterial expression of a sesquiterpenoid biosynthetic gene (Ari1) from Penicillium roqueforti". J. Biol. Chem. 268 (6): 4543–8. PMID 8440737. http://www.jbc.org/cgi/pmidlookup?view=long&pmid=8440737. Retrieved 2008-12-03. 
18. ^ Chen FC, Chen CF, Wei RD (1982). "Acute toxicity of PR toxin, a mycotoxin from Penicillium roqueforti". Toxicon 20 (2): 433–41. doi:10.1016/0041-0101(82)90006-X. PMID 7080052. http://linkinghub.elsevier.com/retrieve/pii/0041-0101(82)90006-X. Retrieved 2008-12-03. 
19. ^ Siemens , Zawitowski J (1993). "Occurrence of PR imine, a metabolite of Penicillium roqueforti, in blue cheese". Journal of Food Protection 56 (4): 317–319. 
20. ^ Nielsen KF, Dalsgaard PW, Smedsgaard J, Larsen TO (April 2005). "Andrastins A-D, Penicillium roquefortiMetabolites consistently produced in blue-mold-ripened cheese". J. Agric. Food Chem. 53 (8): 2908–13. doi:10.1021/jf047983u. PMID 15826038. 
21. ^ Larroche C, Arpah M, Gros J-B (1989). "Methyl-ketone production by Ca-alginate/Eudragit RL entrapped spores of Penicillium roqueforti". Enzyme and Microbial Technology 11 (2): 106–112. doi:10.1016/0141-0229(89)90068-9. 
22. ^ Solomon, N. A.; Demain, A. L. (1985). Biology of Industrial Microorganisms. Reading, Mass: Benjamin/Cummings Pub. Co., Advanced Book Program. ISBN 0-8053-2451-8. 

This article is based on text originally from a report of the United States Environmental Protection Agency.