DEGRADATION OF 1,4-DICHLOROBENZENE BY XANTHOBACTER-FLAVUS-14P1

Xanthobacter flavus 14p1 was isolated from sludge of the river Mulde b y selective enrichment with 1,4-dichlorobenzene as the sole source of carbon and energy. The bacterium did not use other aromatic or chloroa romatic compounds as growth substrates. During growth on 1,4-dichlorob enzene stoichiometric amounts of chloride ions were released, Degradat ion products of 1,4-dichlorobenzene were identified by gas chromatogra phy-mass spectrometry analysis, 3,6-Dichloro-cis-1,2-dihydroxycyclohex a and 3,6-dichlorocatechol were isolated from culture fluid, 2,5-Dichl oromuconic acid and 2-chloromaleylacetic acid as well as the decarboxy lation product 2-chloroacetoacrylic acid were identified after enzymat ic conversion of 3,6-dichlorocatechol by cell extract. 1,4-Dichloroben zene dioxygenase, dihydrodiol dehydrogenase, and catechol 1,2-dioxygen ase activity were induced in cells grown on 1,4-dichlorobenzene. The r esults demonstrate that 1,4-dichlorobenzene degradation is initiated b y dioxygenation and that ring opening proceeds via ortho cleavage.