Almost all forms of ethanol production use the sugar and starch found in sugarcane and corn grain. Producing biofuel from the biomass of the plant is still too expensive in comparison, and this is due to the lignin in the plant. Biofuels are produced from the cellulose in the plants, but in order to extract the cellulose from the lignin, the biomass must be soaked in hot acid, an expensive treatment.
A new study, recently published in the journal Science, explains that by genetically modifying the plants, much of the lignin can be removed, avoiding the need to soak the biomass in hot acid, and greatly reducing the overall cost of the biofuel production process.
By genetically modifying plants to remove a key gene needed for lignin production, the scientists discovered that the plants grew with far less lignin, and that 80% of the cellulose within the plant could then be extracted without the need for the acid treatment. Only 18% of the cellulose in a normal plant can usually be extracted without the acid treatment.
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One of the main problems with removing most of the lignin in the plant is that the lignin is what gives the plant structure and strength. Removing it results in far shorter plants, reducing the yield of biofuel from the crop.
Working on this problem, researchers at Lawrence Berkley National Laboratory have managed to create a way to only remove the lignin from parts of the plant, but not all; allowing most of the cellulose to be easily removed, but without compromising the structural integrity of the plant.
The next stage of the study will be to transfer this genetic modification to biofuel producing plants such as switchgrass or poplar.
Richard Hilton, the CEO of Ceres, who have also been researching methods to remove the expensive acid treatment phase of biofuel production, commented that by eliminating the acid phase, the cost of converting the cellulose into usable sugars could fall by as much as $1 a gallon.