Dechlorination of 1,1,1-Trichloro-2,2-bis( p -chlorophenyl)ethane by Aerobacter aerogenes

Abstract

Whole cells or cell-free extracts of Aerobacter aerogenes catalyze the degradation of 1,1,1-trichloro-2,2-bis( p -chlorophenyl)ethane (DDT) in vitro to at least seven metabolites: 1,1-dichloro-2,2-bis( p -chlorophenyl)ethylene (DDE); 1,1-dichloro-2,2-bis( p -chlorophenyl)ethane (DDD); 1-chloro-2,2-bis( p -chlorophenyl)ethylene (DDMU); 1-chloro-2,2-bis( p -chlorophenyl)ethane (DDMS); unsym-bis( p -chlorophenyl)ethylene (DDNU); 2,2-bis( p -chlorophenyl)acetate (DDA); and 4,4′-dichlorobenzophenone (DBP). The use of metabolic inhibitors together with p H and temperature studies indicated that discrete enzymes are involved. By use of the technique of sequential analysis, the metabolic pathway was shown to be: DDT → DDD →DDMU →DDMS → DDNU → DDA → DBP, or DDT → DDE. Dechlorination was marginally enhanced by light-activated flavin mononucleotide.