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Discovered by the ancient Mayans, the seeds of the cacao tree have long been perceived as an energy source. For the eighteenth century English aristocracy, chocolate was a symbol of status and sexual vitality. Today it’s a mass-produced sweet pick-me-up. Now scientists have reinvented chocolate as a source of clean energy for the future.
The hydrogen biotechnology team at the University of Birmingham was working on developing a clean sustainable source of hydrogen. Headed by microbiologist Professor Lynne Macaskie, their aim was to power a fuel cell by feeding sugar-loving bacteria. She explains how they sourced the ingredients, ‘Cadbury’s chocolate factory is just down the road so it seemed a good alliance to contact them and scrounge some waste.’
Producing the hydrogen fuel uses the harmless bacteria Escherichia coli. Professor Macaskie describes the process: ‘You put the bacteria into a big pot, stir it, tip in the waste which feeds it and the hydrogen gas is piped out. The reaction happens almost instantly. Hydrogen gas is directed into a gadget called a fuel cell which converts the gas into electricity which we used to power an electric fan.’
The feeding frenzy doesn’t stop there as the waste products of the bacteria are fed to a second bacteria to produce more hydrogen. Yet another process uses the leftover bacteria to recycle expensive palladium metal from catalytic converters. The bacteria are coated with the palladium and can be recycled as an ingredient in the fuel cell.
Professor Macaskie believes they have achieved their aim of producing hydrogen with zero harmful emissions and waste reduction. The carbon dioxide inevitably produced is carbon neutral. This means, ‘that the carbon dioxide was derived from plants trapping carbon dioxide as sugar in the photosynthesis process. So if you’re using sugar as part of your process, you’re recycling something that’s plant made and not burning fuel from fossil reserves.’
The next step is to test exactly how much electricity can be generated. In the meantime we can now enjoy our chocolate guilt-free. It’s also feasible that our kitchen compost heap could power our kitchen gadgets! The team has already had interest from developing countries interested in producing eco-friendly hydrogen using readily available sugary crops. Sweet!
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