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Bacteria Turn Fats and Oils Into Plastics
Microbial fermentation is turning vegetable oils and animal fats into
biodegradable industrial materials. Certain microorganisms, when grown
on fats and oils, can produce poly(hydroxyalkanoate) polymers, or PHAs.
When fed excessive carbon and deprived of other nutrients, bacteria
like Pseudomonas resinovorans produce these plasticlike substances
as a survival mechanism. The polymers are either rigid or elastomeric,
depending on their chemical structure, the organism that produces them,
and the fat or oil feedstock.
Since PHAs break down naturally over time, they are suitable for a
wide range of environmentally friendly medical and consumer products
ranging from adhesives to plastics and films. Scientists want to control
the PHA properties to make them suitable for diverse industrial uses.
The properties vary with the fatty acid composition of the feedstock
source.
Richard D. Ashby, Daniel
K.Y. Solaiman, USDA-ARS Hides,
Lipids, and Wool Research Unit, Wyndmoor, Pennsylvania; phone (215)
233-6483 [Ashby] -6476 [Solaiman].
Tanning Innovation Might Boost Meat Safety
Microorganisms present on the hair of food animals at the time of slaughter—such
as Escherichia coli O157:H7, Salmonella, and Listeria
monocytogenes—can contaminate meat and sometimes cause illness
in consumers. Research shows that removing hairs from cattle hides before
skinning significantly reduces the threat of meat contamination. Now,
a 10-year-old hair-removal method has been improved to reduce both processing
costs and environmental impact.
The patented process begins with spraying a sodium sulfide solution
on the carcass hide, which breaks protein bonds within hair fibers and
allows their easy removal. Then a sulfide-neutralizing agent is applied.
Packers can now remove most of the hair, split the hide, and send the
top layer for tanning and the rest for other uses. This saves time and
money, allows early-stage inspection of the hide's grain layer,
and reduces shipments of low-quality hides to tanners. The method is
being implemented by Future Beef Operations, LLC, in a new Kansas plant.
Andrew G. Gehring,
USDA-ARS Hides, Lipids, and Wool
Research Unit, Wyndmoor, Pennsylvania; phone (215) 233-6491.
Cool, New Aquaculture Research Center
A 50,000-square-foot facility for investigating production of cool-
and cold-water species of food fish has been opened in Leetown, West
Virginia. Work there will complement catfish research under way at Stoneville,
Mississippi, and on warm-water species at Stuttgart, Arkansas. The focus
will be on fish genetics and breeding, health, nutrition, and production—all
for species that thrive in water temperatures ranging from 39°F
to 68°F. Initially, these will be trout and other salmonids, but
studies of other species will be added later.
Domestic aquaculture producers now meet 10 percent of U.S. consumer
needs for fish and rank 10th in the world for value of production. Eventually,
12 scientists at the new center will be developing new collaborative
programs with other state and national research institutions.
William Hershberger,
National Center
for Cool and Cold Water Aquaculture, Leetown, West Virginia; phone
(304) 724-8340.
Measuring Your Antioxidant Protection
Some important antioxidants, such as lycopene and beta-carotene, circulate
in the lipid portion of human plasma. Until now, assays for antioxidant
capability have only peered into the water portion, where water-soluble
antioxidants like vitamin C settle. As a result, the effects of lipid-loving
antioxidants seemed to disappear in human blood.
A new assay that measures oxidation in both lipid and water environments
gives a more accurate picture of total antioxidant capacity of biological
samples. It should one day help health professionals make better recommendations
about individual antioxidant needs to protect against cancer, heart
disease, and other age-related diseases thought to evolve from oxidative
damage to cell components.
Kyung-Jin Yeum, Jean Mayer
USDA Human Nutrition Research Center
on Aging at Tufts University, Boston, Massachusetts; phone (617)
556-3128.
More Potent Chromium in Your Diet
The typical Western diet barely provides adequate levels of the essential
trace element chromium—set at 35 micrograms (mcg) daily for men,
25 mcg for women. Since the mineral appears to improve insulin function,
a shortfall can reduce the body's ability to remove excess sugar
from the blood. High sugar intakes, trauma, and hard exercise can increase
chromium excretion, worsening an already marginal status.
Extra dietary chromium from supplements may improve glucose tolerance
in people who have difficulty managing their blood sugar levels. A patent
is being sought for a more potent formulation that is more readily absorbed—up
to 50 percent better—than chromium picolinate. That formulation
is the best-absorbed and most popular chromium supplement sold today.
The new technology, already available for licensing, combines chromium
and the amino acid histidine.
Richard A. Anderson,
USDA-ARS Nutrient Requirements
and Functions Laboratory, Beltsville, Maryland; phone (301) 504-8091.
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