Increased expression of laccase by the addition of phthalates in Phlebia tremellosa.

Phthalates, which are used as plasticizers in the plastics industry, are widely used and have been dispersed into the environment. A white-rot basidiomycete Phlebia tremellosa, which showed good growth in media containing various hormone-mimicking compounds, degraded benzylbutylphthalate and diethylphthalate by up to 30% and 80%, respectively, under liquid culture conditions for 9 days. A laccase cDNA from P. tremellosa was cloned by a rapid amplification of cDNA ends (RACE)-PCR technique, and found to encode 1832 nucleotides. Its deduced amino acid sequence showed 80.7% identity when compared with that of Phlebia radiata, and 64.8% identity when compared with that of Trametes versicolor. When this fungus was grown under suitable conditions for degrading phthalic esters, the laccase activity and its transcript level were both highly increased.