Allene Rosalind Jeanes

Allene Rosalind Jeanes

Allene Rosalind Jeanes. Photo courtesy National Center for Agricultural Utilization Research, U.S. Department of Agriculture.

Government chemist Allene Rosalind Jeanes (1906–1995) investigated bacteria that could serve as tiny living factories in fermentation vats to produce several important polymeric substances, instead of resorting to laboratory chemicals and the high temperatures and pressures often needed to effect polymerization.

A native of Waco, Texas, Jeanes stayed in her hometown for college. After earning a bachelor’s degree from Baylor University, she headed west to earn a master’s from the University of California at Berkeley. She taught at Alabama’s Athens College for five years before returning to school at the University of Illinois, where she received her Ph.D. in organic chemistry in 1938.

With doctorate in hand, Jeanes went to work for the National Institutes of Health in Washington, D.C. After a few years she moved to the U.S. Department of Agriculture’s Northern Regional Research Lab (NRRL) in Peoria, Illinois. There she worked on polysaccharides (polymers made of thousands of sugar molecules). Starch is a polysaccharide that is found in wheat, corn, rice, and potatoes. Cellulose is also a polysaccharide, and it is found in cotton, wood, and paper.

Jeanes soon became interested in a polysaccharide called dextran. Dextran was hard to find in nature, at least in large quantities, which made her research difficult. But she took advantage of an unexpected opportunity when a puzzled soft-drink company in Peoria sent a bottle of viscous, gooey root beer to NRRL to see if the scientists could determine what had gone wrong. It turned out that the root beer had been contaminated with a kind of bacteria that just happened to produce dextran, and the dextran was thickening the root beer. The bacteria were just what Jeanes needed. She isolated the microbes and used them to make all the dextran she needed. NRRL was already famous for its expertise in culturing useful bacteria; during World War II the lab had developed a deep-tank fermentation process for making the antibiotic penicillin.

In the meantime, some researchers in Sweden and in England were contemplating using dextran as a blood plasma extender. A plasma extender cannot carry oxygen to the cells like real blood can, but in emergency situations, like wartime or car accidents, it can keep a person who has lost a lot of blood alive long enough to get to a hospital for a transfusion. Jeanes and her colleagues were considering this potential use of dextran when, in 1950, the Korean War erupted and the United States soon became involved. Jeanes and colleagues went to work and in a short time they were able to make a successful dextran-based blood plasma extender. The new product was rushed into use by army doctors, nurses, and medics. After the war, civilian doctors began using it.

Another important discovery made by Jeanes and her team was xanthan gum, also a polysaccharide synthesized by bacteria. Xanthan gum is good for thickening ice cream and other foods. It also keeps foods like oil and vinegar from separating. If you shake a bottle of salad dressing, the oil and vinegar will appear to mix, but the oil does not truly dissolve. In time, the two substances will separate again. But with xanthan gum added, the oil and vinegar will stay together long enough to get from bottle to plate. Xanthan gum is found in everyday products from ketchup and steak sauces to cough syrups and skin lotions. And the petroleum industry uses huge quantities of xanthan gum to thicken the drilling mud that carries solid materials up to the surface.

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