In New Scientist (via InkyCircus):
Microbiologist Lynne Mackaskie and her colleagues at the University of Birmingham in the UK have powered a fuel cell by feeding sugar-loving bacteria chocolate-factory waste. “We wanted to see if we tipped chocolate into one end, could we get electricity out at the other?” she says.
The team fed Escherichia coli bacteria diluted caramel and nougat waste. The bacteria consumed the sugar and produced hydrogen, which they make with the enzyme hydrogenase, and organic acids. The researchers then used this hydrogen to power a fuel cell, which generated enough electricity to drive a small fan (Biochemical Society Transactions, vol 33, p 76).
The process could provide a use for chocolate waste that would otherwise end up in a landfill. What’s more, the bacteria’s job doesn’t have to end once they have finished chomping on the sweet stuff. Mackaskie’s team next put the bugs to work on a production line that recovers precious metal from the catalytic converters of old cars.