Manganese peroxidase, with molecular mass of 45 kDa, was purified from the white-rot fungus Cerrena unicolor BBP6 and named MnP-BBP6. The optimum temperature and pH of MnP-BBP6 activity were 60 degrees C and 4.5, respectively. MnP-BBP6 showed high stability toward many metal ions. It could effectively decolorize many types of dyes including Congo red (53.9% in 12 h), methyl orange (77.6% in 12 h), Remazol brilliant blue R (81.0% in 5 h), bromophenol blue (62.2% in 12 h) and crystal violet (80.9% in 12 h). With gallic acid as the redox mediator, azure blue was decolorized by 63.1% in 24 h. In addition to dye decolorization, purified MnP-BBP6 also presented significant effect on denim bleaching, with up to 3-fold increase in reflectance without mediators. With such strong decolorizing activity, MnP-BBP6 was demonstrated to be a potential peroxidase in the textile industry, and its decolorization potential was greatly enhanced with the addition of redox mediators.