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NEWS OF THE WEEK ALTERNATIVE
ENERGY
BIOETHANOL BOOST Interest in cellulose-based ethanol is rising with the price of gasoline
A
THE CURE? Cellulosic ethanol would join traditional corn-based ethanol as an alternative motor fuel.
S PRESIDENT BUSH STEPS UP
the call for cellulose-based ethanol to help cure the U.S.'s "addiction to oil," fuel etha nol producers, enzymes developers, and the financial community are boosting their commitment to the technology worldwide. Last week, the banking firm Goldman Sachs announced that it has invested $27 million in Iogen, an enzymes producer that operates the world's only cellulose ethanol facility. The plant, in Ontario, has the capacity to make 3 million to 4 million L of ethanol per year by breaking down and fermenting about 40 tons per day of wheat,
DRUG
oat, and barley straw with steam, enzymes, and yeast. The announcement followed by days Bush's latest speech promot ing the inclusion of $150 million in next year's federal budget for research into new ways of mak ing ethanol. Goldman Sachs, which joins Royal Dutch/Shell as a major in vestor in Iogen, says its money will be used to accelerate Iogen's commercialization program. Io gen seeks to build a plant, likely in Idaho or western Canada, that will produce around 170 million L of ethanol per year. Such a facility, however, would cost upward of
ANALYSIS
NEW TOOL FOR DRUG DELIVERY KINETICS Uptake and release of drug-carrier's cargo in cells is quantified in real time
A
NOVEL MOLECULAR TRANS-
porter system carries probe molecules across cell mem branes and allows the uptake of the transporter and the release of its molecular cargo to be monitored as the processes occur. The method could one day ferry drugs into cells. The system, developed by chem-
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TFA = trifluoroacetate
FIREFLY GLOW Luciferin (blue) cargo is released from octaarginine transporter (green) when disulfide linker (red) is cleaved. 10
C & E N / MAY 8, 2006
istry professor Paul A. Wender and coworkers at Stanford University, consists of a peptide transporter linked by a disulfide bond to lu ciferin, a drug stand-in that is ex ploited to study the kinetics of the delivery system. The researchers administer the luciferin-transporter conju gate to cells stably transfected w i t h luciferase (J. Am. Chem. Soc., published
online April 25, dx.doi.org/10.1021/ ja0586283). They also can adminis ter the conjugate to transgenic animals that express lucifer
$300 million, money that no fi nancial backer has yet put up. Brian Duff, a biochemical pro cess engineer at biofuels consult ing firm BBI International, says cellulosic ethanol is economically feasible at today's gasoline prices. Yet the risks associated with build ing the first plant are huge. "No body wants to be the guinea pig," he says. "There's a lot of 'wait and see' going on." Meanwhile, interest is growing in Europe. Abengoa, a Spanish en ergy company, is building a plant designed to make more than 5 mil lion L of cellulosic ethanol annu ally. Iogen, Shell, and Volkswagen are studying a facility in Germany. And the enzymes producer Genencor, which worked with the U.S. government to bring down the price of cellulase enzymes, just joined a French consortium look ing to produce ethanol from pulp m i l l waste.—MICHAEL MCCOY
ase in all their cells, but that work has yet to be published. In the cells, Wender explains, the conjugate encounters a reduc ing environment that cleaves the disulfide bond and releases its cargo of luciferin. Each molecule of free luciferin generates a photon when it interacts with luciferase, the enzyme responsible for the luminescent glow of the firefly. The Stanford team uses a special camera to measure the lumines cent signal from the cells. " T h e camera allows us to quantify precisely the timing and amount of the release in real time," Wender says. "The assay is fast and should facilitate studies on new transporters and linkers. Importantly, it does not require sacrifice of the animals. "We now have a powerful tool that could greatly impact funda mental research by enabling the use of a wider range of probes," he continues. "It could also im pact therapy by enabling a broader range of molecules to be used for intervention in various diseases." —MICHAEL FREEMANTLE
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