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Genes for jeans: engineered enzyme improves fabric
OAK RIDGE, Tenn., Oct. 4, 1995 Thanks to altered genes, it can stonewash jeans without stones and make them look better than ever. It can "eat" the paper wastes that occupy 40 percent of U.S. landfill space while removing ink from newspaper to make recyclable paper. It can convert wood to sugar, which can be turned into ethanol for fuel.
"It" is a new strain of bacteria discovered and altered by researchers at the Department of Energy's (DOE) Oak Ridge National Laboratory (ORNL). The altered bacteria rapidly produce cellulase, an enzyme used in fabric-finishing detergents to smooth fabric, such as blue jeans, by removing puffy "pills" (knots in cloth that make it rough) from knitted material. Tests show that the bacterial enzyme produces a more attractive textile product than the commercially used acid cellulase fermented by fungi.
Craig Dees, a researcher in ORNL's Health Sciences Research Division who genetically altered the special bacteria, says that the bacterial enzyme has several advantages over the fungal enzyme. "The bacteria produce much more enzyme than fungi can in the same time," he says. "There is less back staining, or smearing of the blue dye, on the white areas of the jean cuffs. The bacterial enzyme can withstand a wider range of acidity levels and temperatures during textile processing, and our bacterial cellulase is not eaten by protease, a protein that may be added to detergents.
"The bottom line is that replacing acid cellulase with the bacterial cellulase should save money. And stones are not needed with the ORNL enzyme to stonewash jeans!" .
Dees says the bacterial enzyme has been tested also on the wood chips used for bedding 200,000 mice used in ORNL research to help find better ways to diagnose and treat genetic diseases. The bedding is replaced every few days, and the old chips are discarded. About 12 percent of the trash in the government's Oak Ridge Reservation's landfill consists of mouse bedding.
"After immersing mouse bedding in a solution of engineered enzyme," Dees says, "we reduced its volume and weight by 50 percent in 8 days. The waste was turned to useful sugars by the enzymes."
Tim Scott, head of ORNL's Bioprocessing Research and Development Center in the Chemical Technology Division, has immobilized the genetically altered bacteria on beads in a fluidized bioreactor. His experiments have shown that these bacteria effectively convert cellulose to wood sugar. Other bacteria can be used to turn this sugar into alcohols, including the liquid fuel ethanol that can be used to power automobiles.
The bacterium has also been shown to grow in high concentrations in a solution of compounds that are toxic to many bacteria, such as saccharinic acid, furfural, and cinnimyl alcohol. Thus, the bacterium and its enhanced enzyme will be useful in modifying industrial waste streams that contain cellulose, such as those from paper production.
The project is funded by DOE's laboratory-directed research and development funds.
You can learn more about this research and many other exciting projects by visiting ORNL on Oct. 21, 1995, during its Community Day event. Many of our facilities will be open to the public that day. For additional information, call ORNL Public Affairs, 865-574-4160.
ORNL, one of the Department of Energy's multiprogram research laboratories, is managed by Lockheed Martin Energy Systems, which also manages the Oak Ridge K-25 Site and the Oak Ridge Y-12 Plant.