Scientists from the United States Department of Agriculture used a commercial enzyme to reduce overall costs and greenhouse gases emissions of ethanol production from grain.
The researchers found that the enzyme helps extract the water from ethanol byproducts that are used in animal feeds - called dried distillers grains with solubles - for cattle, swine and poultry. This could significantly reduce the amount of energy and water needed for ethanol production from grain as well as its byproducts.
The study was conducted at an Illinois-based commercial facility Center Ethanol Company that produces 54 million gallons of ethanol and 172,000 tons of D.D.G.S. from corn each year.
The enzymes were provided by Genecor, a major developer and manufacturer of industrial enzymes. Genecor is now part of the DuPont Industrial Biosciences. The researchers added a pound of the enzyme to every 1,000 pounds of corn.
After corn grains had been fermented into ethanol, the leftover slurry of corn solids and water called "stillage" was put into a centrifuge where much of the water was extracted. The stillage was transferred to an evaporator then to a dryer powered by natural gas for another evaporation process.
The scientists found out the amount of energy needed by the dryer to make the stillage suitable for D.D.G.S. production was reduced by 14 percent because the enzymes boosted the water extraction process in the centrifuge.
All in all, the researchers estimate that using the enzymes would reduce facility water use by 10 percent, electricity consumption by 2.4 percent and natural gas consumption by 12 percent.
A model using this data indicated that this would result in a reduction of GHG emissions of around 8,000 tons annually from a mid-sized ethanol facility with an annual production of 50 million gallons of grain ethanol.
"The production of grain ethanol is a key component in our nations efforts to increase the supply of transportation fuels derived from renewable plant resources. The results from this investigation give us new tools for increasing the efficiency of grain ethanol production and for protecting our natural resource base," Agricultural Research Service administrator Edward B. Knipling said.
Scientists from A.R.S., David Johnston and Andrew McAloon led the study. Members of the research team are Professor Milroad Dudukovic and student Ana Beatriz Henriques from the Department of Energy, Environmental and Chemical Engineering of Washington University in St. Louis.
source: APEC-VC Korea
