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BEST-L  July 2008

BEST-L July 2008

Subject:

Grass: It's Not Just For Grazing

From:

"BAYSINGER,GRANT A" <[log in to unmask]>

Reply-To:

BAYSINGER,GRANT A

Date:

Wed, 16 Jul 2008 17:59:55 -0400

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text/plain

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Parts/Attachments

text/plain (148 lines)

BEST-

From the July 2008 Issue of Biomass Magazine

Grass: It???s Not Just for Grazing
We know cows like it???and by eating certain varieties, they give 
more milk. So do these grasses??? higher sugar content also mean 
greater ethanol output?
By Susan Aldridge

Grass is everywhere???on golf courses, football fields, parks, in 
your garden and, of course, wherever cows are content.

Could we use it for transport fuel?

That idea is under consideration in several places around the 
world, including Wales???and in Wales, cows in fact may be a guide 
for researchers studying cellulosic ethanol.
Steve Kelly, a molecular biologist at Swansea University in Wales, 
is one scientist working on a process that may eventually let 
motorists tank up on ???grassohol??? from the very meadows past 
which they drive on their next holiday.

Kelly???s is a two-step process, using high-sugar, low-lignin, 
highly digestible variants of ryegrass. These grasses were 
developed at the Institute of Grassland and Environmental Research 
at Aberystwyth University in Wales through conventional 
crossbreeding techniques, particularly with the AberDart and 
AberMagic varieties (see sidebar on page 33).

Researchers have deliberately avoided the laboratory techniques of 
genetic modification, which directly alter the genetic makeup of 
the plants, because it is controversial in Europe. Among the 
concerns is that genetically modified (GM) crops will spread into 
the natural ecosystem. Grass is wind-pollinated, and the 
scientists don???t want to risk gene transfer to non-GM plants.

Juiced
The first step for Kelly and colleagues is processing the grass to 
extract a water-soluble ???juice??? that contains fructans 
(fructose oligomers and polymers). Kelly???s team has cloned genes 
for enzymes that can hydrolyze these fructans. They insert the 
fructans into the fermenting yeast to optimize the process.

The second step is fermenting the relatively dry, stable 
lignocellulose fraction residue. This involves use of enzymes that 
can break down the plant cell walls.

Iain Donnison, leader of the bioenergy and biorenewables program 
at the Aber Bio Centre at Aberystwyth University and one of 
Kelly???s main collaborators, says preliminary calculations 
suggest ryegrass could be as good as or better than wheat or sugar 
beets as a source of ethanol.

Grassy Landscapes
Swansea???s Kelly is well-schooled. He studied molecular biology 
with Nobel Prize winner Sir Paul Nurse, who shared the 2001 prize 
for work on key regulators of the cell cycle. That positions Kelly 
to push forward a genomic approach in meeting the challenges of 
producing ethanol from biomass.

Wales, on England???s west, is famous for its grassy landscapes. 
No surprise, it is trying to build its biofuels involvement in 
part on all that grass. The Welsh government is funding a planned 
Centre of Excellence in Biorefining at the universities of 
Aberystwyth, Bangor and Swansea, with additional funding from the 
European Union.

In a region where mining once drove the economy but has since 
diminished in importance, the purpose of the centre is to provide 
research and guidance for businesses to create new employment and 
preserve existing jobs. Backers seek commercial partners as well. 
???This,??? says Kelly hopefully, ???is a good time to invest in 
this area of science.???

He pushes ahead with his work on ryegrass to establish a better 
understanding of the grasses and the key microbes associated with 
processing them.

Ryegrass represents an important prospective source of biomass 
because it is present on two-thirds of agricultural land in the 
U.K. At the same time, EU efforts to reform agricultural subsidies 
encourage farmers to decrease the number of animals grazing on 
their land. ???So, farmers are wondering what they can do with 
this excess of grass.??? Donnison says.

Cows Like It
Grass stands out from other prospective perennial feedstocks for 
its high soluble carbohydrate (sugar) content. Indeed, IGER has 
bred ryegrasses from varieties such as AberDart and AberMagic to 
select for this high-sugar content, originally because cattle 
grazing on high-sugar grasses gave a higher milk and meat yield. 
Now it appears that the same grasses can also provide a high 
potential ethanol yield.

Donnison???s team is scaling up. ???We believe ethanol from grass 
could be comparable in yield to wheat and beets,??? Donnison says, 
???and the key advantage is that it could be low-input, as it is a 
perennial crop. If it is grown with clover, which fixes nitrogen, 
then not much fertilizer is needed.???

The work tracks research published earlier this year showing the 
economic feasibility of producing ethanol from switchgrass. 
Researchers at the USDA and the University of Nebraska-Lincoln 
carried out field trials on 10 plots of 15 acres to 20 acres each 
on marginal cropland on 10 farms in the U.S. Midwest. Measuring 
inputs, biomass yield, estimated ethanol output, greenhouse gas 
emissions and net energy, researchers found that switchgrass 
produced more than six times the renewable energy compared with 
nonrenewable energy consumed. Researchers also calculated that 
emissions of greenhouse gases from switchgrass ethanol would be 94 
percent lower than regular gasoline.

Producing Hydrogen
Meanwhile, back in the U.K., Richard Dinsdale of the University of 
Glamorgan in Pontypridd, Wales, has found another use for grass. 
Collaborating with IGER researchers, Dinsdale is working at 
producing hydrogen.

Using anaerobic organisms???mainly Clostridium cultures???to 
produce hydrogen and methane, Dinsdale and colleagues are now 
working on a variety of techniques to improve hydrogen yield from 
grass stocks.

Biogas can include both methane and hydrogen, depending on the 
nature of the fermentation process. It can be piped off, 
compressed and used as a transportation fuel.

Dinsdale???s figures suggest that, as a transport fuel, biogas can 
produce three times more mileage than either ethanol or biodiesel 
per unit of land. He and his colleagues are currently building two 
pilot plants to establish key engineering parameters and seeking 
funding to extend the work beyond 2009.

Biogas is already used in Germany, Austria, Sweden and Italy???but 
not yet much in the U.K. or the United States. Dinsdale believes 
biogas ought to have a big future as a transportation fuel in the 
U.K. However, existing liquid-fuel infrastructure inhibits its 
development.

In any case, researchers say that 30 acres can fuel a London bus 
for a year. If true, evidently the cows knew it first.

Susan Aldridge is a London-based freelance writer and editor 
specializing in biotechnology, medicine, health and chemistry.

--
BAYSINGER,GRANT A

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