Degradation of 1,1,1-trichloro-2,2-bis (4-chlorophenyl) ethane (DDT) by brown-rot fungi

Twelve species of brown-rot fungi (BRF) have been investigated for their ability to degrade 1,1,1-trichloro-2,2-bis (4-chlorophenyl) ethane (DDT). In potato dextrose broth (PDB) medium, Gloeophyllum trabeum, Fomitopsis pinicola and Daedalea dickinsii showed a high ability to degrade DDT. 1,1-Dichloro-2,2-bis (4-chlorophenyl) ethane (DDD), 1,1-dichloro-2,2-bis (4-chlorophenyl) ethylene (DDE) and 4,4-dichlorobenzophenone (DBP) were detected as metabolic products of DDT degradation by G. trabeum in PDB medium. The DDT degradation pathway in G. trabeum is proposed, which differs from the proposed pathways in bacteria and other fungi, particularly in the transformation of DDE to DDD. On the other hand, DBP was not detected as a metabolic product of DDT degradation in FeSO₄-deficient cultures of G. trabeum, whereas DDE and DDD were detected, indicating the involvement of an iron-dependent reaction. Only DBP was detected from DDT, DDE and DDD degradation via a chemical Fenton reaction under conditions similar to those in G. trabeum cultures. These compounds may be directly transformed to DBP via a Fenton reaction.