A peroxidase, DyP, produced by the fungus Dec 1 having the ability to
decolorize dyes was purified. DyP contains 17% sugar comprising GlcNAc and Man.
The molecular mass of DyP was estimated to be 60 kDa and the isoelectric point (pl)
was determined to be 3.8. DyP degraded various dyes, and also phenolic compounds of
2,6-dimethoxyphenol and guaiacol. However, veratryl alcohol, abbreviated VA, a
substrate of lignin peroxidase, was not degraded by DyP.
Molasses was utilized by Dec 1 to produce DyP as carbon and energy source. Within
10 g/l of molasses concentration, decolorization activity of Dec 1 toward RB5
gradually increased. However, at more than 20 g/l of molasses concentration, the
inhibitory effect on the decolorizin g activity of Dec 1 was observed. As the activity of
purified DyP was inhibited by 10 g/l of molasses concentration, this indicates that
molasses has a stimulative effect on the decolorization activity of Dec 1, but has an
inhibitory effect on the DyP activity.
Dec 1 also produced Aryl Alcohol Oxidase (AAO). The role of AAO in the Dec 1
decolorization process of dyes has been observed to be as follows: the first role was
that H2O2
was produced by AAO oxidation of Veratryl Alcohol (VA) to veratraldehyde
and then utilized by the peroxidase DyP. In the cultivation of Dec l, the presence of
H2O2
and veratraldehyde has been detected. The second role was that the
polymerization of products produced by DyP oxidation of a simplified RB5, AQ-2’,
was prevented by AAO. This was confirmed by the result that the molecular weight of
the products was reduced in the mixed decolorization of DyP and AAO.
A new versatile peroxidase named TcVP1 was purified from the Dec 1 culture. Purified
TcVP1 behaved as Manganese Peroxidase (MnP) at pH 5, and the enzyme functioned
as a Lignin Peroxidase (LiP) at pH 3. As TcVP1 decolorized preferentially azo dyes,
co-application of TcVP1 and DyP conducted complete decolorization of anthraquinone
dye, RB5, in vitro to colorless products.
Keywords: Peroxidase, DyP, Anthraquinone dye, Aryl alcohol oxidase, Thanatephorus cucumeris Dec 1, Versatile oxidase, TcVP1, Simplified RB5, AQ2’, Veratryl alcohol, VA, Veratraldehyde, Hydrogen peroxide, Molasses, Manganese peroxidase, MnP, Lignin peroxidase, LiP.
