Metabolism of phenol and resorcinol in Trichosporon cutaneum

Abstract

T. cutaneum was grown with phenol or resorcinol as the carbon source. The formation of .beta.-ketoadipate from phenol, catechol and resorcinol was shown by a manometric method using antipyrine and also by its isolation and crystallization. Metabolism of phenol begins with o-hydroxylation. This is followed by ortho-ring fission, lactonization to muconolactone and delactonization to .beta.-ketoadipate. No meta-ring fission could be demonstrated. Metabolism of resorcinol begins with o-hydroxylation to 1,2,4-benzenetriol, which undergoes ortho-ring fission yielding maleylacetate. Isolating this product leads to its decarboxylation and isomerization to trans-acetylacrylic acid. Maleylacetate is reduced by crude extracts to .beta.-ketoadipate with either NADH or NADPH as a cosubstrate. The enzyme catalyzing this reaction was separated from catechol 1,2-oxygenase [EC 1.13.11.1], phenol hydroxylase [EC 1.14.13.X] and muconate-lactonizing enzyme on a diethylaminoethyl-Sephadex A50 column. It was purified some 50-fold, as was the muconate-lactonizing enzyme. Methyl-, fluoro- and chlorophenols are converted to a varying extent by crude extracts and by purified enzymes. None of these derivatives is converted to maleyacetate, .beta.-ketoadipate, or their derivatives. Cells grown on resorcinol contain enzymes that participate in the degradation of phenol and vice versa.