EcoSeed

Grass genes, computer simulation employed for biofuel productivity

By Katrice R. Jalbuena

Next-generation biofuel advocates want non-food biomass such as fibrous grasses.

With more and more countries seeking to bring down their emissions by increasing the amount of biofuel in their fuel mix, the race is on to see which biomass feed stock can be the source of a sustainable biofuel industry.

While ethanol is an established biofuel, it has come under criticism for using food-based feedstock such as corn and sugarcane. Advocates for the next generation of biofuel are lobbying for the use of non-food biomass, such as fibrous grasses as well as residue from the wood processing and agricultural industries.

Genes from grass

Researchers from the University of Cambridge and Rothamsted Research, with funding from Britain's Biotechnology and Biological Sciences Research Council and Sustainable Bioenergy Centre, have been looking at the genes in grasses and cereal crop responsible for the development of the fibrous, woody parts of grasses such as rice and wheat.

"What we hope to do with this research is to produce varieties of plants where the woody parts yield their energy much more readily - but without compromising the structure of the plant. We think that one way to do this might be to modify the genes that are involved in the formation of a molecule called xylan - a crucial structural component of plants," said Professor Paul Dupree of the University of Cambridge.

Xylan found in grasses is different from other plants. The researchers decided to study the cause of this difference.

They identified a gene found in wheat and rice called GT61 that, when transferred into a plant known as Arabidopsis, allowed it to develop the grass form of xylan.

"As well as adding the GT61 genes to Arabidopsis, we also turned off the genes in wheat grain. Both the Arabidopsis plants and the wheat grain appeared normal, despite the changes to xylan. This suggests that we can make modifications to xylan without compromising its ability to hold cell walls together," explained Dr. Rowan Mitchell of Rothamsted.

The researchers believe that their findings could eventually be used to breed a "multi-use" crop in which the grain could be used for food, while the straw and other woody components could be used to produce energy easily and efficiently.

The researchers published their findings in the journal Proceedings of the National Academy of Sciences.

Computer modeling of the biofuel process

Across the pond, researchers from the University of Illinois also reported on the findings of their research into the sustainability of woody biomass biofuel crops such as switchgrass and Miscanthus, species of fibrous grasses that can grow in marginal land.

Agricultural and biological engineering professor and department head K.C. Ting, with Energy Biosciences Institute research professor Yogendra Shastri and agricultural and biological engineering professors Alan Hansen and Luis Rodriguez, used a computer model to run simulations on the variety of steps needed to transform biomass to biofuel to try and find the best system to minimize the cost of producing biofuel.

The model, called "BioFeed," can be adapted to analyze any region of the world. For the purpose of their research, the U.I. team looked at Miscanthus production in a 13-county region in southern Illinois.

BioFeed found that a major challenge of the emerging biofuel industry in the area would be the need for a vast and steady stream of plant biomass.

"If the biorefinery capacity is 50 million gallons of biofuel per year, you need to deliver roughly 1,500 to 2,000 tons of biomass per day," Mr. Ting said.

While each optimized solution could have its drawbacks, the researchers pointed out, BioFeed would allow those involved in biomass to biofuel production to look and learn from simulations instead of through costly trial and error.

Agronomists recommend that the crop be harvested in January of February, a season of harsh weather in the Mid-West which could increase the expense. BioFeed found that a November harvest would reduce weather-related costs, but would result in higher fertilization costs in the spring.

Next, the researchers are building another model that considers how farmers and other stakeholders are likely to behave given various economic and regulatory factors.

The BioFeed model research, which was funded by BP, is described in papers in the journals Biofuels, Bioproducts and Biorefining; Biological Engineering; Biomass and Bioenergy; and Computers and Electronics in Agriculture.