A NEW INTERMEDIATE IN THE MINERALIZATION OF 3,4-DICHLOROANILINE BY THE WHITE-ROT FUNGUS PHANEROCHAETE-CHRYSOSPORIUM

Phanerochaete chrysosporium ATCC 34541 has been reported to be unable to mineralize 3,4-dichloroaniline (DCA), However, high mineralization is now shown to occur when a fermentation temperature of 37 degrees an d gassing with oxygen are used, Mineralization did not correlate with lignin peroxidase activity. The latter was high under C limitation and low under N limitation, whereas the reverse was true for mineralizati on. The kinetics of DCA metabolism was studied in low N and low-C and C- and N-rich culture media by metabolite analysis and (CO2)-C-14 dete rmination. In all cases, DCA disappeared within 2 days, and a novel hi ghly polar conjugate termed DCAX accumulated in the growth medium. Thi s metabolite was a dead-end product under C and N enrichment, In oxyge nated low-C medium and in much higher yield in oxygenated low-N medium , DCAX was converted to DCA-succinimide and then mineralized. DCAX was purified by high-performance liquid chromatography and identified as 3,4-dichlorophenyl)-alpha-ketoglutaryl-delta-amide by high-performance liquid chromatography and mass spectroscopy, gas chromatography and m ass spectroscopy, and nuclear magnetic resonance spectroscopy. The for mation of conjugate intermediates is proposed to facilitate mineraliza tion because the sensitive amino group of DCA needs protection so that ring cleavage rather than oligomerization can occur.