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Bacteria are helping convert citrus waste into ethanol, acetic acid and
carbon dioxideall industrial products that could be made using ARS
technology. Citrus processing creates more than 800,000 tons of dried
citrus waste annually that must be disposed of in an environmentally
acceptable way. Currently, it's processed into low-value animal feed.
ARS researchers used enzymes to ferment the waste's simple sugars and
developed a filter system to trap peel oil. They used yeast to convert
the sugars to ethanol and E. coli bacterium to break down the more
complex sugars from the oil. Ethanol is a biofuel and acetic acid can be
used in many food and industrial products such as vinegar, flavor
components and organic solvents. Carbon dioxide can be recaptured to make
dry ice. The conversion process takes only 48 hours. Scientists from the
University of Florida collaborated on the research.
Citrus
and Subtropical Products Laboratory, Winter Haven, FL
Karel Grohmann, (813) 293-4133
A leftover from sugarcane processingcalled bagassecan be chemically
modified into an environmentally friendly "cleaner" to remove cotton dyes
from textile mill wastewater. ARS tests found the finely milled,
chemically treated bagasse, called quarternized resin, readily bound about
28 times as much Remazol Brilliant Red reactive dye as did regular
bagasse. Scientists estimate the recyclable bagasse-based resin would
clean wastewater for less than half the cost of activated sludge or
chemical bleaching methods now used by the textile industry.
Food Physical Chemistry
Research, Peoria, IL
Joseph A. Laszlo, (309) 681-6322
ARS researchers have found a way to prevent a modified cotton product
known as Cellulose III from reverting to regular cotton, or Cellulose I,
when exposed to moisture. Cellulose III is used in cotton clothing.
Originally, British scientists found that treating cotton with liquid
ammonia caused subtle changes in the crystal structures of cotton fiber
and yarn. Special processing conditions resulted in a much stronger
sewing thread than was possible with conventional caustic treatments.
Yarn treated in a similar way was found to produce a smooth fabric with
improved wash-and-wear ratings. But the new fiber would return to
Cellulose I when it got wet, causing some decrease in the improved
properties. Several scientists have experimented with temperature,
pressure and other methods to develop a stable Cellulose III product. ARS
tests showed that using ammonia vapors and high pressure (100-1700 pounds
per square inch) would result in complete and irreversible conversion to
Cellulose III. Regular cotton was immersed in ammonia and subjected to
high pressure in a device called a Parr bomb. Resulting Cellulose III was
stable in boiling water. (PATENT 5,322,524)
Southern Regional Research
Center, New Orleans, LA
Timothy Calamari, (504) 286-4265
Last updated: October 29, 1996
Return to: Quarterly Report
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Last Modified: 02/11/2002
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