A new polyphenoloxidase test for distinguishing between wood-rotting fungi

Abstract

White-rot fungi causing the white decay of wood, secrete polyphenol oxidase type enzymes which catalyze the oxidation of diphenols to quinones. If the substrate also contains amino acids, they can be oxidized secondarily to a red pigment, the intensity of which depends on the activity of oxidation oxoenzymes. This finding was used for devising a quick test to demonstrate the oxidases secreted into the cultivation medium by wood-rotting fungi. As substrates we used hydroquinone and glycine. We tested a total of 89 species and 131 strains of wood-rotting fungi. Simultaneously, we compared the newly devised test with the most common test for the detection of polyphenoloxidases, with the guaiacol test. It follows from the results that the new test, in which the intensity of the red colour was estimated colorimetrically, permits to divide the wood-rotting fungi into two groups, the positively and the negatively reacting ones. This division does not fully coincide with that obtained by means of the guaiacol test.