Enzymology of Lignin Metabolism in Actinomycetes
This research will characterize the structural forms, substrate specificities, enzyme reaction kinetics, and catalytic mechanisms of action of a group of extracellular lignin peroxidases produced by ligninolytic Streptomyces species. It is also intended to express and amplify expression of the lignin-induced peroxidase of Streptomyces viridosporus by gene cloning in order to better define the role of this lignin oxidizing enzyme in lignin degradation and solubilization. The lignin-induced peroxidase gene of S. viridosporus will also be compared for sequence homologies with the lignin peroxidase gene of Phanerochaete chrysosporium using gene probes. This research will increase scientific understanding of how plant residues are decomposed by microorganisms. Ultimately, the knowledge gained will lead to the development of economically viable technologies by which plant residues can be used to produce useful chemicals biologically, and to new technologies for carrying out industrial processes such as paper and chemical production using less energy and producing less toxic chemical wastes as by-products. In turn, the research can, therefore, lead to a less energy intensive industry in the United States, which will help to reduce our dependence on the burning of fossil fuels, a major source of the carbon dioxide which is creating the greenhouse effect and undesirable warming of the Earth.