From the archive, originally posted by: [ spectre ]
Chocolate Generates Electrical Power / 01 June 2006
Willy Wonka could have powered his Great Glass Elevator on hydrogen
produced from his chocolate factory.
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
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.
Place the bacteria in a vat with hydrogen and liquid waste from spent
converters, and the enzymes again get to work. The same hydrogenase
used to produce hydrogen splits the gas into its constituents,
generating electrons that react with palladium ions in the solution.
This forces the palladium out of the solution, and it sticks to the
bacteria. The palladium-coated bacteria can then be recycled as
catalysts for other projects, Mackaskie says.
From issue 2554 of New Scientist magazine, 01 June 2006, page 25
email : L [dot] E [dot] Macaskie [at] bham [dot] ac [dot] uk