Degradation of water-insoluble dyes by microperoxidase-11, an effective and stable peroxidative catalyst in hydrophilic organic media.
Microperoxidase-11 (MP-11), a heme-containing undecapeptide, derived from horse heart cytochrome c was utilized as a peroxidative catalyst. Catalytic characteristics of MP-11 in hydrophilic organic media were studied using 2,6-dimethoxyphenol as a reducing substrate in a series of organic solvents at various concentrations, indicating that MP-11 was active in water-miscible organic solvents but at least 5% water was compulsory for the catalytic action. Thus, MP-11 was not active in hydrophobic solvents. The pH of the water portion in the media affected the reaction rate. The optimal pH was found to be 9, where a release of protons from either an oxidizing or reducing substrate to the media was facilitated. The decolorization of water-insoluble synthetic dyes by MP-11 in 90% methanol was attempted. MP-11 showed effective decolorization activities against either azo or anthraquinone dyes. The degradation pathway for Solvent Orange 7 was investigated in detail, showing that MP-11 catalyzed the oxidative cleavage of the azo linkage to generate 1,2-naphthoquinone and 2,4-dimethylphenol as key intermediates.
Wariishi
Hiroyuki
H
Faculty of Agriculture, Kyushu University, 6-10-1 Hakozaki, Higashi-ku, Fukuoka 812-8581, Japan. hirowari@agr.kyushu-u.ac.jp
Kabuto
Mari
M
Mikuni
Junko
J
Oyadomari
Masafumi
M
Tanaka
Hiroo
H
D000818:Animals; D001391:Azo Compounds / Q000378:metabolism; D001673:Biodegradation, Environmental; D002384:Catalysis; D004396:Coloring Agents / Q000378:metabolism*; D003574:Cytochrome c Group / Q000737:chemistry; D004785:Environmental Pollutants / Q000378:metabolism; D006736:Horses; D006863:Hydrogen-Ion Concentration; D007220:Industrial Waste / Q000517:prevention & control; D007700:Kinetics; D010544:Peroxidases / Q000302:isolation & purification / Q000378:metabolism*; D011748:Pyrogallol / Q000031:analogs & derivatives* / Q000378:metabolism; D012995:Solubility; D012997:Solvents / Q000494:pharmacology
D001391:Azo Compounds; D004396:Coloring Agents; D003574:Cytochrome c Group; D004785:Environmental Pollutants; D007220:Industrial Waste; D012997:Solvents; D011748:Pyrogallol; C010120:pyrogallol 1,3-dimethyl ether; D010544:Peroxidases; C021799:microperoxidase