Enzymes Boost Ethanol Production Efficiency
McGinnis April 9, 2007
As ethanol production increases, so does the demand for suitable
Affordable, plentiful and easy to work with, corn is currently the
feedstock of choice in the United States. So Agricultural Research Service (ARS) scientists at the Eastern Regional
Research Center (ERRC)
in Wyndmoor, Pa., are investigating ways to avoid overburdening the corn market
as ethanol production expands.
Annual U.S. ethanol production is projected to increase from 5 billion
gallons in 2006 to as many as 13 billion gallons in 2009. So what options will
ethanol producers have? One solution is to increase conversion efficiency.
Johnston, a food technologist in the ERRC's
Conversion Science and Engineering Research Unit, is investigating new
processes using protease enzymes from microbial and fungal sources to make
ethanol more efficiently. He has found that the enzymes make more nutrients
available for the yeast, expediting fermentation of sugars. Protease enzymes
can also facilitate the process of dewatering the solids that remain after the
ethanol has been extracted.
Working with Vijay Singh, an agricultural engineer at the
University of Illinois, Johnston conducted a
field trial at a small wet-milling facility in Panang, Malaysia. They soaked
U.S. corn in water for several hours and then applied the enzymes (provided by
biotechnology company Genencor International
Inc., of Palo Alto, Calif.). The scientists found that adding enzymes
during processing increased starch recovery, just as it had in laboratory
The starches can be used in more than 1,000 different products, from
paper and sheet rock to high fructose corn syrup and ethanol. Economic analysis
will be the next step, and Johnston and Singh are planning to replicate the
trial at several more commercial facilities.
This is one of many ERRC research projects related to improving
understanding and production of biofuels.
more about the research in the April 2007 issue of Agricultural
ARS is the U.S. Department of
Agriculture's chief in-house scientific research agency.