Friday, October 10, 2008

Batteries to be Mushroom Powered?

Mushrooms – edible fungus – one of nature’s wonder foods. Mushrooms are not only loaded with fiber and provide vitamins such as thiamine, riboflavin, niacin, biotin, cobalamins, and ascorbic acid; they also provide some minerals including iron, selenium, potassium, and phosphorous.

Nothing adds sparkle to a salad like fresh, organic mushrooms. What would a cheese and mushroom omelet be without the mushrooms? Boring – that’s what!

Now it would appear that mushroom has a hidden talent. It may not be just for cooking anymore. Apparently, mushroom enzyme could strip pollutants from fuel cell. Chemists at Oxford University say they have isolated a chemical that could one day be used as a clean alternative to the expensive, polluting and rare metals used today in fuel cells and conventional batteries.

They have demonstrated that laccase, an enzyme produced by fungi that grow on rotting wood, can be used as a cheaper, greener and more efficient catalyst. Fuel cells use chemical reactions to produce emissions-free electricity; however, current technology is expensive and requires electrodes that contain rare metals such as platinum.

Christopher Blanford, a chemist at Oxford, is working to replace the use of these rare and precious metals with cheap and abundant enzymes. Laccase has now been shown to equal the catalytic performance of platinum when used to speed up the reactions on the electrode of a fuel cell. The fungi, such as Trametes versicolor, use laccase to break down lignin, a component of the cell walls of plants. Lignin is highly resistant to degradation and is what we refer to as the “fiber” in our foods.

However, Blanford found that it was also highly effective at reacting oxygen with hydrogen to produce water and electricity. “Portable power sources from enzyme-coated electrodes could one day replace the batteries now in everyday use,” he said.

Canada, the US and the UK alone discard approximately 3 billion batteries a year. This is equivalent to 200,000 tons of unrecycled material. Not only are throwing away and not reclaiming the precious metals we use in the electrodes such as platinum; the most crucial element of a battery, zinc, is due to run out in 2037 according to the British Geological Survey. The good news is that there is no shortage of plants that can be grown to produce the enzyme laccase.

John Loughhead, executive director of the UK Energy Research Centre, welcomed the Oxford group's work. "Much of the benefit, if they make it work, is not necessarily cleaner energy; but, that we no longer need to exploit scarce mineral resources, produce unpleasant by-products, and consume energy in manufacturing processes if we can grow the things naturally," he said.

Doug Parr, the chief scientist at Greenpeace, also welcomed the research; but added: "I would ask about the scale of production required [for the enzyme] — what's the yield per mushroom? How much area does it take? As a high-value product that may not be too much of a barrier; but, a GM fungi would need to be contained in some way."

Loughhead said it would be some time before the technology was available commercially. "My gut feel is this is a possibility for the post-2020 world: discovery to deployment is historically around 20 years so I'd put my money on towards 2030 if it works — probably before nuclear fusion."

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