White-Rot Fungi Demonstrate First Biodegradation of Phenolic Resin

Phenolic resins, phenol-formaldehyde polymers previously thought to be nonbiodegradable, are produced at an annual rate of 2.2 million metric tons in the United States for many industrial and commercial applications. Three independent lines of evidence established their biodegradability with the white-rot fungus Phanerochaete chrysosporium. Chromatic transformation of growth medium (yellow to pink) indicated initial biodegradation of the resin 3 days after inoculation. A degradation product, 13C-labeled phenol, was detected with gas chromatography-mass spectroscopy. Scanning electron micrographs revealed physical evidence of degradation. This is the first demonstrated biodegradation of these phenol-formaldehyde polymers and stands as a platform for investigation into bioremediation and biorecycling of phenolic resins.