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).Link
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.