Scientists discover fungus that eats CDs

LONDON - Compact disc users beware: Your prized music or data could be under attack. Scientists have discovered a fungus which, under the right conditions, will literally eat compact discs and render the information on them completely useless.

Victor Cardenes, a geologist at a leading Spanish research institute, made the discovery on a trip to the Central American country of Belize, where some friends showed him a CD which had a strange discolouration that left it almost transparent, and unplayable.

Intrigued, he took it back to Madrid, where he put the sample under an electron microscope at the Superior Council for Scientific Research.

There, he found that a fungus had burrowed into the disc from its outer edge, and eaten up the thin aluminium reflecting layer and the polycarbonate resin that comprises the CD.

Information is stored on CDs by a pattern of "pits" in the aluminium layer, which is held in the resin matrix.

That is then covered in a transparent lacquer. To read the disc, laser light is shone onto the aluminium; the presence or absence of a pit is then read as a digital 0 or 1. If the pits cannot be located, the CD is unreadable.

"If you look at the CD from the shiny side, in the places where the fungus has been you can see through to the other side," Dr Cardenes said.

Biologists at the council concluded that the fungus belonged to a common genus called Geotrichum, but admitted they had never before seen this particular species.

The cooler and drier weather in Madrid caused the fungus to stop growing - suggesting that it thrives on tropical heat and humidity.

Hans Hofstraat, chief organic chemist at the electronics giant Philips - which invented the CD in 1973 - said the case is "probably a freak incident caused by extreme weather conditions" and insisted the fungus poses no threat to the billions of discs used around the world.

- INDEPENDENT