Production of ligninolytic enzymes and synthetic lignin mineralization by the bird's nest fungus Cyathus stercoreus

• Published in: Applied microbiology and biotechnology Vol. 52; no. 5; pp. 689 - 697
• Main Authors: Sethuraman, A, Akin, D.E, Eriksson, K.E.L
• Format: Journal Article
• Language: English
• Published: Berlin Springer 01.11.1999; Springer Nature B.V
• Subjects: Amino Acid Sequence; Amino acids; Ammonium; Bacteria; Basidiomycota - enzymology; biobleaching; Biodegradation, Environmental; Biological and medical sciences; Biology of microorganisms of confirmed or potential industrial interest; biopulping; Biotechnology; bleaching; Carbon sources; Chromatography; Cinnamates - metabolism; Cyathus stercoreus; Electrophoresis, Polyacrylamide Gel; Enzyme engineering; Enzymes; Fermentation; Fundamental and applied biological sciences. Psychology; Fungal Proteins - isolation & purification; Fungal Proteins - metabolism; Glucose - metabolism; Hydrogen-Ion Concentration; Laccase; Lignin; Lignin - metabolism; ligninolytic enzymes; Manganese; Manganese - metabolism; manganese peroxidase; Methods. Procedures. Technologies; Microbiology; Mineralization; Miscellaneous; Mission oriented research; Molecular Sequence Data; Oxidoreductases - isolation & purification; Oxidoreductases - metabolism; peroxidases; Peroxidases - metabolism; Production of selected enzymes; pulping; Sequence Homology, Amino Acid; Substrate Specificity; Tartrates - metabolism; Ultrafiltration; white-rot fungi; Biodegradation; Purification; Enzyme; Manganese peroxidase; Industrial application; Basidiomycetes; Biosynthesis; Ligninolytic enzyme; Optimization; Operating conditions; Fungi; Characterization; Peroxidases; Enzymatic activity; Mineralization; Substrate specificity; Production; Microorganism culture; Oxidoreductases; Physicochemical properties; Thallophyta; Laccase; Lignin derivatives
• ISSN: 0175-7598; 1432-0614
• DOI: 10.1007/s002530051580

Production of ligninolytic enzymes and degradation of (14)C-ring labeled synthetic lignin by the white-rot fungus Cyathus stercoreus ATCC 36910 were determined under a variety of conditions. The highest mineralization rate for (14)C dehydrogenative polymerizates (DHP; 38% (14)CO(2) after 30 days) occurred with 1 mM ammonium tartrate as nitrogen source and 1% glucose as additional carbon source, but levels of extracellular laccase and manganese peroxidase (MnP) were low. In contrast, 10 mM ammonium tartrate with 1% glucose gave low mineralization rates (10% (14)CO(2) after 30 days) but higher levels of laccase and manganese peroxidase. Lignin peroxidase was not produced by C. stercoreus under any of the studied conditions. Mn(II) at 11 ppm gave a higher rate of (14)C DHP mineralization than 0.3 or 40 ppm, but the highest manganese peroxidase level was obtained with Mn(II) at 40 ppm. Cultivation in aerated static flasks gave rise to higher levels of both laccase and manganese peroxidase compared to the levels in shake cultures. 3,4-Dimethoxycinnamic acid at 500 micromolars concentration was the most effective inducer of laccase of those tested. The purified laccase was a monomeric glycoprotein having an apparent molecular mass of 70 kDa, as determined by calibrated gel filtration chromatography. The pH optimum and isoelectric point of the purified laccase were 4.8 and 3.5, respectively. The N-terminal amino acid sequence determined from other basidiomycete laccases. Information on C. stercoreus, whose habitat and physiological requirements for lignin degradation differ from many other white-rot fungi, expands the possibilities for industrial application of biological systems for lignin degradation and removal in biopulping and biobleaching processes.