Tannic acid induces transcription of laccase gene cglcc1 in the white-rot fungus Coriolopsis gallica

Laccase, a phenoloxidase enzyme secreted by white-rot fungi, has a significant role in the degradation of lignin and environmental pollutants. Coriolopsis gallica is a ligninolytic basidiomycete that produces high levels of this extracellular enzyme. A laccase gene cglcc1 from this fungus has been cloned and sequenced. The capacity of C. gallica to efficiently degrade polyphenols has been successfully applied in our laboratory to the biotreatment and decolorization of several industrial wastewaters. This study focused on the effect of tannic acid, a natural compound widely distributed in plants, on the production of laccase activity by C gallica. Our results showed an evident increase of extracellular laccase levels when C. gallica was grown in the presence of tannic acid. Concentrations of 50 and 100 muM of this compound increased laccase activity when compared with control samples grown without tannic acid. In addition, we found an increase in laccase transcript levels in C. gallica grown in culture media supplemented with tannic acid. The role of tannic acid was shown to be an inductor of laccase activity in this fungus, due to the enhancement of expression of the laccase gene at the transcriptional level.