Bacteria used to make fuel cells that convert hydrogen into energy

July 17th, 2008 - 1:05 pm ICT by ANI  

Washington, July 17 (ANI): Scientists have combined the efforts of two kinds of bacteria which help make fuel cells that convert hydrogen into energy.

Hydrogen has three times more potential energy by weight than petrol, making it the highest energy-content fuel available.

Research into using bacteria to produce hydrogen has been revived thanks to the rising profile of energy issues.

A total of 7 million tonnes of food is wasted in countries like the UK in a year. The majority of this is currently sent to landfill where it produces gases like methane, which is a greenhouse gas 25 more potent than carbon dioxide.

But now, following some major advances in the technology used to make biohydrogen, this waste can now be turned into valuable energy.

Researchers have combined the efforts of two kinds of bacteria to produce hydrogen in a bioreactor, with the product from one providing food for the other.

This technology has an added bonus: leftover enzymes can be used to scavenge precious metals from spent automotive catalysts to help make fuel cells that convert hydrogen into energy.

There are special and yet prevalent circumstances under which micro-organisms have no better way of gaining energy than to release hydrogen into their environment, said Dr Mark Redwood from the University of Birmingham.

Microbes such as heterotrophs, cyanobacteria, microalgae and purple bacteria all produce biohydrogen in different ways, he added.

When there is no oxygen, fermentative bacteria use carbohydrates like sugar to produce hydrogen and acids. Others, like purple bacteria, use light to produce energy (photosynthesis) and make hydrogen to help them break down molecules such as acids.

These two reactions fit together as the purple bacteria can use the acids produced by the fermentation bacteria.

With a more advanced pre-treatment, biohydrogen can even be produced from the waste from food-crop cultivation, such as corn stalks and husks.

Tens of millions of tonnes of this waste is produced every year in the UK. Diverting it from landfill into biohydrogen production addresses both climate change and energy security.

The University of Birmingham has teamed up with Modern Waste Ltd and EKB Technology Ltd to form Biowaste2energy Ltd, which will develop and commercialise this waste to energy technology.

In a final twist, the hydrogenase enzymes in the leftover bacteria can be used to scavenge precious metals from spent automotive catalysts to help make fuel cell that converts hydrogen into electricity, said Professor Lynne Macaskie.

So nothing is wasted and an important new application can be found for todays waste mountain in tomorrow’’s non-fossil fuel transport and energy, she added. (ANI)

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