title: New pathway for degradation of sulfonated azo dyes by microbial peroxidases of Phanerochaete chrysosporium and Streptomyces chromofuscus.
abstract: Pathways for the degradation of 3,5-dimethyl-4-hydroxy-azobenzene-4'-sulfonic acid (I) and 3-methoxy-4-hydroxyazobenzene-4'-sulfonamide (II) by the manganese peroxidase and ligninase of Phanerochaete chrysosporium and by the peroxidase of Streptomyces chromofuscus have been proposed. Twelve metabolic products were found, and their mechanisms of formation were explained. Preliminary oxidative activation of the dyes resulted in the formation of cationic species, making the molecules vulnerable to the nucleophilic attack of water. Two types of hydrolytic cleavage were observed. Asymmetric splitting gave rise to quinone and diazene derivatives, while symmetric splitting resulted in the formation of quinone monoimine and nitroso derivatives. These unstable intermediates underwent further redox, oxidation, and hydrolytic transformation, eventually furnishing 11 organic products and ammonia.
authors.affiliation: Department of Bacteriology and Biochemistry, College of Agriculture, University of Idaho, Moscow 83844.
authors.forename: S
authors.initials: S
authors.lastname: Goszczynski
authors.forename: A
authors.initials: A
authors.lastname: Paszczynski
authors.forename: M B
authors.initials: MB
authors.lastname: Pasti-Grigsby
authors.forename: R L
authors.initials: RL
authors.lastname: Crawford
authors.forename: D L
authors.initials: DL
authors.lastname: Crawford
mesh_terms: D000363:Agaricales / Q000201:enzymology*; D001391:Azo Compounds / Q000138:chemical synthesis / Q000378:metabolism*; D001557:Benzenesulfonates / Q000138:chemical synthesis / Q000378:metabolism*; D001711:Biotransformation; D004396:Coloring Agents / Q000138:chemical synthesis / Q000378:metabolism; D015394:Molecular Structure; D010105:Oxygenases / Q000378:metabolism*; D010544:Peroxidases / Q000378:metabolism*; D013302:Streptomyces / Q000201:enzymology*
chemical_list: D001391:Azo Compounds; D001557:Benzenesulfonates; D004396:Coloring Agents; D010544:Peroxidases; C051129:manganese peroxidase; D010105:Oxygenases; C044391:ligninase