New products and more market demand for alfalfa and soybeans can be expected by Midwest farmers in the 21st century. An ARS agricultural engineer working with University of Wisconsin scientists have devised a method to fractionate soybean and alfalfa herbage in the field. Fractionation is the physical separation of herbage into a number of parts, each having properties and uses different from the original material. Until now, wet fractionation was conducted in a central processing facility. The drawback: Herbage, which contains about 80 percent water, had to be transported from the field to the processing facility. Waste liquid then had to be either dehydrated or transported back to the field as liquid fertilizer. In the summer of 1999, the researchers performed the first fieldside demonstration of soybean wet fractionation. For the most part, commercially available machines were used, but a hammermill—originally used for pulverizing grain by forcing it through screens—was modified to rupture the herbage without reducing fiber size. Next, the researchers will develop a mobile field processor. Working like a combine, it could cut the crop and wet-fractionate it while juice is being processed in the field. In this demonstration, the energy cost for producing 6.4 tons of herbage and 3.5 tons of juice per hour was about 76 cents per wet ton. Potential products from the fiber portion include cattle feed, chemical feedstocks, mats for filtering pollutants from water, enzymes derived by growing fungi on the fiber, and building materials. Products from the juice fraction include food- and feed-grade protein concentrates, carotenoids, antioxidants and industrially valuable enzymes. The work was done under a CRADA with industry.

U.S. Dairy Forage Research Center, Madison, WI
Richard G. Koegel, (608) 264-5149, rkoegel@facstaff.wisc.edu

Trace levels of iron can now be detected in biological samples in 2 minutes. Developed by ARS scientists, the new procedure makes use of a special chemical, called a pyoverdine, produced by the beneficial bacterium Pseudomonas fluorescens. Under ultraviolet light, pyoverdine normally takes on a greenish-yellow glow that quickly subsides as iron is absorbed. But ARS scientists saw a strikingly different scene when they mixed a solution—called an acetate buffer—with pyoverdine and added the combination to test samples containing as little as 10 parts per billion of iron. Instead of quickly subsiding, the glow steadily increased for several minutes. And the more iron that was present, the slower the rate of increase. Pyoverdine could be put into a simple kit that could be used to monitor increased iron levels in urine as patients are treated with an antimalarial drug. Or someday the chemical may become part of more sophisticated tools—fiber-optic biosensors—that could monitor iron levels during water, food, pharmaceutical, and chemical processing.

National Center for Agricultural Utilization Research, Peoria, IL
Patricia J. Slininger, (309) 681-6286, slininpj@mail.ncaur.usda.gov