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The degradation of 2,6-dimethoxyphenol (DMP) and decolorization of Remazol brilliant blue R dye (RBB), added to culture media of Pleurotus ostreatus developed in submerged fermentation, and the laccase, manganese peroxidase and veratryl alcohol oxidase activities produced in these systems were evaluated. Both compounds were removed from the culture medium mainly by enzymatic action. These compounds decreased the specific growth rate and the effect on the maximal biomass values was not important. The enzymatic activities were increased by DMP and/or RBB; however, the DMP showed a higher inducer effect on all enzymes than RBB. On the other hand, the RBB showed a larger inducer effect on manganese peroxidase activity than on the laccases and veratryl alcohol oxidase activities. These results show that DMP was a better inducer of ligninolytic enzymes than dye, and the process of dye decolorization and degradation of DMP requires the action of all enzymes of the ligninolytic complex. [ABSTRACT FROM AUTHOR]

In this work, a gene (lacP83) encoding a Pleurotus ostreatus laccase isoenzyme expressed in submerged fermentation conditions is described. A 2,887 bp sequence was obtained from a genomic library of P. ostreatus by using a PCR inverse strategy. The coding sequence, 1,527 bp long, showed 17 exons and encoded a protein of 509 amino acids, with a putative signal peptide and conserved copper binding domains. The promoter region of the lacP83 gene (466 bp upstream of ATG) contains putative binding transcription factors such as MRE, XRE, a defense response element, and a stress response element. The protein and gene sequences of lacP83 showed, respectively, 90 to 96% and 78 to 92% of similarity to laccases of Pleurotus previously reported. However, it showed differences in its apparent molecular weight and promoter sequence. [ABSTRACT FROM AUTHOR]