
Corn, Crop Residues Offer Cleaner EnvironmentBy Ben Hardin April 14, 1997SAN FRANCISCO, April 14--Leftovers processed from farm
crops could clean drinking water and industrial wastewater, a
U.S. Department of Agriculture scientist
says. An article about a different research approach
involving phytic acid, entitled "Mutant Corn Has Low Phytic Acid," appeared in
Agricultural Research magazine, December 1996. Click
here to view the
article in PDF format. . Chemist Jacob Lehrfeld of USDA's
Agricultural Research Service has
chemically converted low-value agricultural residues such as corn bran into
resins to bind up lead, other metals and some pesticides that contaminate
water. He reports on his research today at the 213th national meeting of the
American Chemical Society under way here. In experiments at the National
Center for Agricultural Utilization Research at Peoria, Ill., Lehrfeld
produced phytic acid resin by heating crop residues or newsprint shreddings
with phytic acid in a slight vacuum. "Phytic acid resin is a natural for cleaning wastewater in
chromium and copper plating industries," said Lehrfeld. "It binds nearly three
times more heavy metal than a similar volume of the petroleum-based sulfonated
styrene-divinylbenzene resin, now widely used in wastewater cleanup." Phytic acid resin currently would be more expensive to make than
the petroleum-based product, Lehrfeld noted. The greatest expense is the phytic
acid, which now sells for about $12 per kilogram in a 50 percent liquid
solution. It is used for treating metals to prevent rust, and in some countries
tiny amounts are added to food oils to inhibit development of rancid flavors.
Phytic acid can be chemically extracted from corn steep liquor, a
byproduct of starch production. Corn steep liquor is the same dark brown,
syrup-like liquid in which USDA scientists at Peoria mass-produced penicillin
more than 50 years ago, launching the antibiotics industry. About 100,000
metric tons of phytic acid could be processed from corn steep liquor produced
in the United States. Today as in the past, corn steep liquor is mixed with corn bran
and dried into a livestock feed. Removing the phytic acid from the corn steep
liquor could result in a more valuable and nutritious feed. That's because
phytic acid binds up calcium, zinc and other trace minerals in the feed and
makes them indigestible for animals with a single stomach, such hogs, chickens
and fish. Besides corn bran, agricultural residues that might be combined
with phytic acid to form resins include ground corncobs, oat hulls, soy hulls
and sugarbeet pulp, Lehrfeld said. In his research, Lehrfeld found that phytic acid resins also
removed some organic chemicals such as the herbicide atrazine from watery
solutions. He is continuing research to pinpoint the conditions in which the
resins quickly and selectively bind to lead, cadmium and other heavy metals.
Lehrfeld has applied for a patent on the production of resins
made with phytic acid and is seeking industrial cooperators to help transfer
the technology to the marketplace. Scientific contact: Jacob Lehrfeld, chemist, National
Center for Agricultural Utilization Research, Agricultural Research Service,
USDA, Peoria IL 61604, phone (309) 681-6320, fax (309) 681-6689, e-mail
[email protected]. U.S. Department of Agriculture | |