cause supercritical fluids have become increasingly important in recent years in research and industry. Supercritical carbon dioxide is used both as a mobile phase in chromatography and for such extractions as caffeine from coffee. The SUNY researchers expected that solvation would alter the fluorescence lifetime of 4-AMP as the solvent relaxed the excited molecules on a picosecond time scale. By measuring phase shifts and demodulations of exciting light modulated at many different frequencies, they calculated fluorescence lifetimes present. The best fit to the data was a spectrum of lifetimes, which they ascribed to 4-AMP molecules complexed with anywhere from one to 14 molecules each of 2-propanol. Also calculated from the data were equilibrium formation constants and enthalpies, entropies, and free energies of 4-AMP/2-propanol complexes. Stephen Stinson
Research on ligninases takes big step forward Efforts to harness for practical purposes the lignin-degrading enzymes of the white rot fungus Phanerochaete chrysosporium have been brought somewhat closer to reality as a result of recently reported research from scientists at Oregon Graduate Center. Michael H. Gold, professor and chairman of the Beaverton-based graduate center's department of chemical and biological sciences, and coworkers have made major contributions toward understanding the biodégradation of lignin, which is the second most abundant natural polymer. Lignin is a random phenylpropanoid matrix that makes up 20 to 30% of woody plants and retards microbial depolymerization of cellulose. Two extracellular enzymes produced by P. chrysosporium, lignin peroxidase and manganese peroxidase, are responsible for the breakdown of lignin. Lignin peroxidase (LiP) was discovered independently in 1983 in Gold's lab and in the labo-
ratory of T. Kent Kirk at the U.S. Forest Products Laboratory in Madison, Wis. Gold's group discovered manganese peroxidase (MnP) the following year. With coworkers Margaret Alic, Janet R. Kornegay, and David G. Pribnow, Gold has now developed the first DNA transformation system for P. chrysosporium [AppL & Environ. Microbiol. 55, 406 (1989)]. The system represents "an important step toward the production of large amounts of ligninases," Gold says. It will also facilitate studies on the regulation and expression of the genes that encode LiP and MnP as well as genetic approaches to structure-function studies of the enzymes. Gold's research is supported by the Department of Energy, Department of Agriculture, and National Science Foundation. Additionally, Gold, Pribnow, and coworkers Mary B. Mayfield, Valerie J. Nipper, and Julie A. Brown have characterized for the first time a
cDNA (that is, a deoxyribonucleic acid copy of a messenger ribonucleic acid) that encodes MnP [/. Biol. Chem., 264, 5036 (1989)]. Combined with the P. chrysosporium transformation system, as well as research by other groups, Gold says, the results of the research on the MnP gene should allow the Oregon Graduate Center scientists to produce large amounts of recombinant LiP and MnP in the near future. LiP and MnP, or modified organisms that produce these enzymes themselves, could find use in a number of bioprocessing applications, Gold says. There are a number of points in the production of paper, for example, where the enzymes might be used in place of traditional chemistry. Also, numerous possibilities exist for the use of these enzymes as nonspecific oxidative reagents for degrading aromatic environmental pollutants such as chlorophenols and dyes. Rudy Baum
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March 27, 1989 C&EN
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