Soltron, an enzyme manufactured in the United States by Solpower Corp., was shown to reduce NOx and other emissions from biodiesel use in a study funded by California's Bay Area Air Quality Management District, according to Matt Cohen, general manager of Solpower. The testing was part of a feasibility study on production and use of biodiesel. During field testing of tailpipe emissions, Soltron added to B20 reduced carbon monoxide, hydrocarbons, particulates and NOx cumulatively an average of 83 percent, and NOx by 5.9 percent. Laboratory testing showed adding Soltron to soy-based B20 reduced NOx 9.4 percent. Soltron also stabilizes and eliminates water contamination and biological growth in biodiesel without toxic biocides, Cohen said.