Depolymerization of low-rank coal by extracellular fungal enzyme systems. III.In vitro depolymerization of coal humic acids by a crude preparation of manganese peroxidase from the white-rot fungus Nematoloma frowardii b19 |
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Authors: | M Hofrichter W Fritsche |
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Institution: | Friedrich-Schiller-Universit?t Jena, Institut für Mikrobiologie, Lehrstuhl Technische Mikrobiologie, Philosophenweg 12, D-07743 Jena, Germany. Fax: +49-03641 6 31237 e-mail: hofrichter@merlin.biologie.uni-jena.de, DE
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Abstract: | The in vitro depolymerization of humic acids derived from German lignite (low-rank coal, brown coal) was studied using a
manganese peroxidase preparation from the white-rot fungus Nematoloma frowardii b19. The H2O2 required was continuously generated by glucose oxidase. Mn peroxidase depolymerized high-molecular-mass humic acids by forming
fulvic-acid-like compounds. The depolymerization process was accompanied by the decolorization of the dark-brown humic acid
fraction soluble in alkaline solutions (decrease in absorbance at 450 nm) and by the yellowish coloring of the fraction of
acid-soluble fulvic-acid-like compounds (increase in absorbance at 360 nm). The Mn peroxidase of N. frowardii b19 has been proved to be highly stable; even after an in vitro reaction time of 7 days in the presence of humic acids, less
than 10% loss in total oxidizing activity was detectable.
Received: 16 September 1996 / Received revision: 16 December 1996 / Accepted: 20 December 1996 |
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