Destruction of Fungal Melanins by Ligninases ofPhanerochaete chrysosporiumand Other White Rot Fungi

Ligninases produced by white rot fungi degraded fungal and synthetic melanins. Ligninases, thus, function as melaninases. Microscopic and chemical evidence showed that this ligninase/melaninase activity was associated with extensive destruction of otherwise resistant melanized cells of the black yeast Phaeococcomyces sp. Each of three isolates of white rot fungi degraded melanins. The ligninase enzyme manganese peroxidase was an efficient degrader of melanins. Synthetic and natural fungal melanins were bleached by cloned manganese peroxidase expressed in a bacterium, indicating that this ligninase alone is capable of melanin degradation. Our findings indicate that melanin‐degrading fungi could be a component of the biological control of some plant pathogens that overwinter as propagules that are protected by melanin.