Yachmenev, who works in the Cotton Textile Chemistry Research Unit at ARS' Southern Regional Research Center (SRRC) in New Orleans, La., has found that ultrasound can intensify enzyme activity during several different types of enzymatic treatments of cotton fibers.

Yachmenev and his SRRC colleagues have shown that introducing ultrasonic energy during enzymatic treatments of cotton fabric results in shorter processing times, less consumption of expensive enzymes, less fiber damage and better uniformity of treatment to the fabric.

Enzymes are protein molecules that can speed up complex chemical reactions. They act as catalysts, substances that initiate or accelerate chemical reactions without themselves being affected. Human saliva, for example, contains amylase, an enzyme that helps break down starchy foods into sugars.

Enzymatic treatments have been used for many years to remove the starch that's added to cotton yarns to smooth and protect them from breaks during weaving. But enzymes are now available for scouring (removing natural waxes and pectins from the surface of cotton fibers), bio-finishing (removing fiber fuzz and pills from fabric surface) and bio-stoning (removing color and softening denim fabrics for a "stone-washed" effect).

Yachmenev says that enzymes use significantly less water, less energy and fewer chemicals than traditional methods. In addition, wastewater from enzymatic treatments is readily biodegradable and does not pose an environmental threat.

However, although enzymatic processing offers many advantages, there are a few drawbacks when compared to traditional methods — chiefly, expensive processing costs and relatively slow reaction rates. Ultrasound technology may help make up for these shortcomings.

ARS is the U.S. Department of Agriculture's chief scientific research agency.