Degradation of non-phenolic lignin by the white-rot fungus Pycnoporus cinnabarinus.
High-molecular-weight lignin was methylated with diazomethane. The lignin (i.e., phenolic lignin) and methylated lignin (i.e., non-phenolic lignin) were mixed with fully bleached softwood pulp. Degradation of the lignin preparations by the white rot fungus Pycnoporus cinnabarinus was studied. After a 3-month incubation with the fungus, over 40% of the non-phenolic lignin and about 70% the phenolic lignin were degraded. The presence of phenolic hydroxyl groups in lignin greatly enhanced the degradation rate of lignin. This study reveals that P. cinnabarinus, an exclusively laccase-producing fungus, is capable of oxidatively degrading both phenolic and non-phenolic lignins. The ability of the fungus to degrade non-phenolic lignin suggests that a laccase/mediator system is involved in the complete degradation of lignin. After the fungal degradation of lignins, the content of carboxylic acids substantially increased for both phenolic and non-phenolic lignins.
Geng
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Department of Wood Science and Engineering, Oregon State University, Corvallis, OR 97331-5751, USA.
Li
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K
D001673:Biodegradation, Environmental; D008031:Lignin / Q000737:chemistry / Q000378:metabolism*; D008745:Methylation; D011124:Polyporaceae / Q000378:metabolism*; D017550:Spectroscopy, Fourier Transform Infrared
D008031:Lignin