Metabolism of gallate in Penicillium simplicissimum

The pathway for the degradation of gallate (3,4,5-trihydroxybenzoate) by a new strain of Penicillium was examined by in vivo and in vitro cell-free systems. The organism was identified as P. simplicissimum (Oud) Thom. It grew optimally at pH 5.5 and 27 degrees C, with 11.75 mM (0.2%) gallate added to the basal salt media. Mycelia grown on gallate accumulated protocatechuate in the medium, and had inducible activity for protocatechuate 3,4-dioxygenase as determined by spectrophotometric and oxygen electrode studies. A NADPH-dependent reductase in the cell-free extract reduced gallate to dihydrogallate. Maleylacetate reductase was also detected in the gallate induced cell-free extract, while beta-ketoadipate was detected as the product produced. The possible steps in the degradation of gallate are discussed.