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THE MICROBIAL FUEL CELL

Revolutionary electrodes

For years, finding suitable electrode material for this cell proved difficult for both researchers and schools alike.

We originally used aluminium foil painted with colloidal graphite, but this electrolysed, generating a current itself.

In 1990 we discovered carbon fibre mats that were used to reduce static electricity on record turntables (apparently to keep the dust away). You could cut about 5 sets of electrodes from a single disc, so whenever we saw these mats in a shop we'd quickly buy them up.

As vinyl was replaced by CDs, the mats were no longer made, so we had to find an alternative. A major use of the carbon fibre sheet we now obtain in bulk is in the bodywork of Formula 1 racing cars.

Several post-16 biology syllabuses in the 1980s and '90s mentioned the use of mediators such as methylene blue or tetrazolium salts in practical studies of respiration. The microbial fuel cell provided a novel method of undertaking such work, using baker's yeast to generate electricity. If you were lucky enough to find a suitable type, the fuel cell could even power a small motor!

Based largely on the research of Dr Peter Bennetto, formerly of King's College, London, this practical exercise gave ample scope for individual projects. For example, alternative substrates to glucose, different temperatures and types of yeast may easily be compared. Several students won prizes at international science fairs working with this cell, and a major UK brewery once approached us as they wished to use the cell to test the viability of their yeast cultures.

This work also proved highly motivating for younger students and was supported at this level by educational television broadcasts by Yorkshire TV and the BBC in the United Kingdom during the 1990s.

Biological fuel cells are not as popular as they once were, and an authoritative academic review of the topic in 2001 pointed out that the NCBE's cell was the only one of its type now available in the world.

ADDITIONAL RESOURCES

Copyright © National Centre for Biotechnology Education, 2006 | www.ncbe.reading.ac.uk