10WWW.CEN-ONLINE.ORG JULY 6, 2009

DOW CHEMICAL is planning a pilot project with algae biofuel start-up Algenol Biofuels to con-vert waste CO 2 into ethanol. The biorefinery is

to be located in Freeport, Texas, at Dow’s largest manu-facturing site.

The project is contingent on Algenol’s receiving a Department of Energy grant for up to $25 million, or no

more than half the cost of the $50 million facility. The rest of the capital would be provided by Algenol, which would also own and oper-ate the plant. Dow would contribute 25 acres of land, the CO 2 supply, and techni-cal expertise.

Algenol has been a quiet contender in the nascent algae biofuel boom. By choice, the firm has not raised any venture capital,

CEO Paul Woods says. Instead, Algenol’s activities, and its 100 employees, have been funded by the company’s founders, including Woods, who retired from a suc-cessful career in pharmaceuticals at age 38.

The company’s unusual algae also set it apart. Al-genol claims its CO 2 -hungry, single-cell cyanobacteria produce sugar and contain enzymes that enable one-step conversion into ethanol, which the algae then ex-crete. The algae, the salt water they live in, and the etha-nol are all packaged in bioreactors that let in sunlight. The algae are engineered to survive high alcohol levels.

In contrast, most biofuel firms, such as Solazyme, are interested in algal oils that can be made into biodiesel, gasoline, or other petroleum-like products. For those companies, getting the oil out of the individual algal cells has been a high hurdle (C&EN, Jan. 26, page 22).

Algenol’s one-step biology is what attracted Dow, says Steve Tuttle, bioscience business director with Dow’s ventures and business development arm. “It fits with Dow’s advancements in polymer films. We can create an environment in the bioreactor where the al-gae perform the best,” he says. And, Tuttle adds, Dow’s chemists and engineers will help design a process that can scale up for commercialization.

But fuel-quality ethanol must be distilled from the bioreactor condensate, which is a major focus for the pilot plant, Woods acknowledges. “We are not going to rely on old technology,” he says. “We will use advanced membrane technology and separations that are more energy efficient.” —MELODY VOITH

RESEARCHERS in Japan have pushed to the single-atom limit the sensitivity of the chemical spectroscopy method called electron energy loss

spectroscopy (EELS). The advance in EELS’s analyti-cal resolving power provides scientists the ability to pinpoint in solids the locations of lone atoms such as impurities and identify them chemically ( Nat. Chem., DOI: 10.1038/nchem.282).

In an EELS experiment, researchers irradiate a solid specimen with an electron beam and measure the element-specific decrease in beam energy (the energy loss) caused by interactions between the beam and sample atoms. Commonly used in conjunction with transmission electron microscopy (TEM), EELS can often reveal the chemical identity of atoms in the nanometer-sized area probed by the TEM beam.

A standard way to boost the spatial resolution of both methods is to increase the beam energy (up to about 400 keV), which narrows the electron beam

toward atomic dimensions. But therein lies a trade-off: Raising the acceleration voltage focuses the beam but typically destroys sample structures. Lowering the beam energy spares the specimen but destroys the focus. Both problems dash chances for single-atom analysis.

To sidestep those problems, Kazu Suenaga and Yuta Sato of the National Institute of Advanced Industrial Science & Technology, Tsukuba, and coworkers modi-fied their microscope with special electron focusers known as aberration correctors and then tuned the TEM beam energy to just 60 keV, an uncommonly low magnitude. With that setup, the group probed carbon nanotubes loaded with a few fullerene cage molecules that had each been doped with one atom of a foreign element such as calcium or cerium. The team reports that the method revealed the identity and positions of the individual foreign atoms within the nanotubes and differentiated between Ce 3+ and Ce 4+ .

“This is an important advance for imaging the chem-ical state of dopant atoms in fullerene and other carbon materials such as graphene,” says David A. Muller, a professor and TEM-EELS expert at Cornell University. As beam correctors improve and even lower beam volt-ages are used, he adds, it may be possible to extend this approach to more weakly bonded molecular crystals. —MITCH JACOBY

A TEM image (top) reveals the location of five fullerene cages (circles) in a carbon nanotube. An EELS chemical map of the same sample (C is red, Ca is green) shows that each cage contains one calcium atom.

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EELS FINDS ATOMS CHEMICAL SPECTROSCOPY: Electron energy loss spectroscopy pinpoints

single-atom impurities in solids

DOW PLANS ALGAE BIOFUELS PILOT

SUSTAINABILITY: Project will test a process to turn CO 2 into ethanol

Algenol grows photosynthetic algae in bioreactors to produce ethanol.