Oxidation of Crocein Orange G by lignin peroxidase isoenzymes. Kinetics and effect of H2O2.
The ligninolytic enzyme system of Phanerochaete chrysosporium is able to decolorize several recalcitrant dyes. Three lignin peroxidase isoenzymes, LiP 3.85, LiP 4.15, and LiP 4.65, were purified by preparative isoelectric focusing from the carbon-limited culture medium of P. chrysosporium. Based on amino terminal sequences, the purified isoenzymes correspond to the isoenzymes H8, H6, and H2, respectively, from the N-limited culture. The purified isoenzymes were used for decolorization of an azo dye, Crocein Orange G (COG). According to the kinetic data obtained, the oxidation of COG by lignin peroxidase appeared to follow Michaelis-Menten kinetics. Kinetic parameters for each isoenzyme were determined. The inactivating effect of ascending H2O2 concentrations on COG oxidation is shown to be exponential within the used concentration range. The best degree of decolorization of 100 microM COG was obtained when the H2O2 concentration was 150 microM. This was also the lowest H2O2 concentration for maximal decolorization of 100 microM COG, regardless of the amount of lignin peroxidase used in the reaction.
Ollikka
P
P
Department of Biochemistry, University of Turku, Finland. pauli.ollikka@utu.fi
Harjunpää
T
T
Palmu
K
K
Mäntsälä
P
P
Suominen
I
I
D000595:Amino Acid Sequence; D001391:Azo Compounds / Q000378:metabolism*; D001673:Biodegradation, Environmental; D001709:Biotechnology; D003116:Color; D004396:Coloring Agents / Q000378:metabolism*; D006861:Hydrogen Peroxide; D006863:Hydrogen-Ion Concentration; D007527:Isoenzymes / Q000235:genetics / Q000378:metabolism*; D007700:Kinetics; D008969:Molecular Sequence Data; D009282:Naphthalenesulfonates / Q000378:metabolism*; D010084:Oxidation-Reduction; D010544:Peroxidases / Q000235:genetics / Q000378:metabolism*; D020075:Phanerochaete / Q000201:enzymology / Q000235:genetics
D001391:Azo Compounds; D004396:Coloring Agents; D007527:Isoenzymes; D009282:Naphthalenesulfonates; C000607925:crocein orange G; C008710:Orange G; D006861:Hydrogen Peroxide; D010544:Peroxidases; C042858:lignin peroxidase