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Shiitake Mushrooms' Secret May Benefit Earth-Friendly FuelsBy Marcia Wood
November 29, 2005
Fallen logs on the forest floor make a perfect home for Shiitake mushrooms. These fungi--sold as a delicacy in the produce section of your local supermarket--thrive on the downed wood, turning it into sugars that they use for food.
Now, Agricultural Research Service scientists in California are looking at bringing the gourmet mushrooms' mostly unstudied talent indoors. And, as a first step towards doing that, they've found and copied a Shiitake gene that's key to the mushroom's ability to dissolve wood.
Called Xyn11A, the gene carries the instructions that the mushroom uses to make an enzyme known as xylanase. The researchers want to see if a ramped-up version of the gene could be put to work digesting rice hulls or other harvest leftovers.
If enzymes can do that quickly and efficiently in huge vats, or fermenters, at biorefineries, they could help make ethanol and other products a practical alternative to today’s petroleum-based fuels, for example. That’s according to Charles C. Lee, an ARS research chemist.
With colleagues, Lee isolated and tested the Xyn11A gene, the first of its kind to be discovered in Shiitake mushrooms, Lentinula edodes.
Lee did the work with research chemist Dominic W.S. Wong and chemical engineer George H. Robertson. The scientists are based at the ARS Western Regional Research Center in Albany, Calif.
In laboratory experiments, they transferred the Xyn11A gene into yeast. Equipped with the gene, the yeast was able to produce xylanase. In nature, the yeast normally can’t do that.
The researchers described their work earlier this year in Protein Journal.
Next, the scientists will work on engineering the mushroom gene so that it enables yeast or some other organism to produce greater amounts of the xylanase enzyme in less time. Gains in efficiency could help make biorefining of plant-based fuels and other products a practical alternative to petroleum refining.
ARS is the U.S. Department of Agriculture’s chief scientific research agency.