Degradation of azo dyes by cell-free extract from Aeromonas hydrophila var. 24B

The degradation of several azo dyes by cell-free extract from Aeromonas hydrophila var. 24B has been studied. The compounds 4-dimethylaminoazobenzene, 4-diethylaminoazobenzene, 2′-carboxy-4-dimethylaminoazo-benzene, 2′-carboxy-4-diethylaminoazobenzene, 4′-carboxy-4-dimethylaminoazobenzene, and 2′-methoxy-carbonyl-4-dimethylaminoazobenzene were appreciably degraded by the cell-free extract. Azobenzene and 4-carboxyazobenzene were not degraded. Aniline was detected by gas chromatography-mass spectrometry as a degradation product from 4-aminoazobenzene and 4-dimethylaminoazobenzene. 4-DimethyIaminoaniline was detected by gas chromatography-mass spectrometry and spectrophotofluorimetry as a degradation product from 2′-carboxy-4-dimethylaminoazobenzene. The cell-free extract had high substrate specificity for 2′-carboxy-4-dimethylaminoazobenzene.