ANST - woad article in Discover magazine

[Kathryn Norris]

R&D
News of science, technology, and medicine

Ancient Blues
According to legend, the ancient British queen Boadicea daubed herself with
blue dye in A.D. 60 before slicing the Roman Ninth Legion to pieces. The dye
came from the leaves of a plant called woad, the chief source of indigo
until the sixteenth century. Although long since replaced by synthetic
chemicals, the old process may be due for a revival, says Philip John, a
plant biochemist at the University of Reading in England. Those forgotten
techniques, he says, could allow industry to replace some of the chemicals
now used to make dyes for denim.


Using an instruction manual compiled by early American colonists--who
brought the woad plant to North America--John harvested the leaves, crushed
them into a paste, and formed balls the size of grapefruits. He then
fermented them in a vat. He discovered that a bacterium called Clostridium
efficiently converts indigo from woad into a soluble state that can be used
as a dye. "This is a rediscovery of a forgotten biotechnology," says John,
"that could provide us with a less polluting dyeing industry for the next
century."
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RELATED WEB SITES:
Philip John <http://www.reading.ac.uk/AcaDepts/sb/AgBot/john.html>
Engra vings of Woad and Indigo Plants
<http://pluto.clinch.edu/honors/courses/text/woad.html>  from Clinch Valley
College
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<http://www.discover.com/> .

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