Biologist Karen Scott and
biochemist Michael Haas
prepare a reactor of soybean-
derived soapstock for
conversion to biodiesel.
Being stuck in a traffic jam may be a bit more bearable if the aroma
of fresh french fries was in the air, rather than the noxious stink
of fossil fuel exhaust.
When scientists at the Eastern Regional Research Center (ERRC) recently
tested biodiesel fuel produced from soybean soapstockan abundant
but underused byproduct of vegetable oil refiningthey found its
composition, engine performance, and emissions to be comparable to those
of biodiesel fuels presently on the market, which are made from highly
refined edible oils. The french-fry aroma, another typical trait of
current biodiesel fuels, was an added bonus.
Biodiesel is the term given to diesel engine fuels made from agricultural
fats and oils. There is much interest in the use of biodiesel throughout
the world because it is made from renewable resources and reduces air-polluting
emissions by diesel engines.
ARS research chemist Michael
J. Haas and biologist Karen M. Scott teamed with research scientist
Scott Bloomerthen at the international agricultural company Cargill
in Minneapolis, Minnesotato develop a chemical method that converts
all forms of fatty acids found in lipids of soybean soapstock into simple
methyl esters. The researchers have applied for a patent on the method.
Haas, Thomas A. Foglia, and other ARS researchers with ERRC's Hides,
Lipids, and Wool Research Unit in Wyndmoor, Pennsylvania, are interested
in using lower value lipids derived from animal fats, vegetable oils,
and recycled greases as raw materials for biodiesel production. They
want to make biodiesel more attractive economically while reducing use
of imported fossil fuels and increasing use of renewable, agriculture-based
Many commercially available biodiesel fuels are made from refined soy
oil and are then added to diesel, typically at levels of 20 percent
of the mixture's volume. According to Haas, studies show that biodiesel,
used alone or in such blends, can provide much needed lubrication to
fuel systems while also reducing production of polluting exhaust emissions.
Because of these benefits, Haas points out, there is strong interest
in this country and around the world in developing methods to produce
biodiesel from fats and oils.
Originally, methods were designed to produce biodiesel from highly
refined oils. Now Haas, Scott, and Bloomer have modified the technology
to allow use of lower value, less pure lipids, such as soapstock, as
starting materials. This could increase availability of biodiesel while
decreasing its cost.
Soybean oil soapstock is a plentiful and relatively inexpensive byproduct
of edible-oil refining. About 100 million pounds are produced in the
United States every year, and it can be had for one-tenth or less the
cost of refined vegetable oil, Haas says. Currently, it is used mostly
as a cheap source of fat in livestock feeds. However, by implementing
processes such as the one developed by Haas and Bloomer, the agents
in soapstock could one day serve as the source of more than 6 million
gallons per year of diesel engine fuel or fuel additives and in other
applications such as cleaning agents and organic solvents.
Other ARS scientists have patented another method to develop biodiesel
and lubricants, as well as fuel and lubricant additives. This enzymatic
method, invented by ERRC researchers Foglia, William N. Marmer, and
Lloyd A. Nelson, uses animal fats, vegetable oils, rendered fats, and
restaurant grease to produce the fatty acid esters that can be used
as biodiesel and lubricants. Because conversion of grease, in particular,
was very effective and inexpensive, grease-derived biodiesel could be
used in conjunction with soybean oil derivatives to reduce costs.By
Agricultural Research Service Information Staff.
This research is part of Bioenergy and Energy Alternatives, an ARS
National Program (#307) described on the World Wide Web at http://www.nps.ars.usda.gov.
Michael J. Haas is in the
USDA-ARS Hides, Lipids, and Wool Research Unit, Eastern
Regional Research Center, 600 East Mermaid Lane, Wyndmoor, PA 19038;
phone (215) 233-6459, fax (215) 233-6795.