• Mycobiology
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• v.39 no.1
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• pp.64-66
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• 2011

Most fungi possess several hydrogen peroxide-generating enzymes, glucose oxidase and pyranose oxidase. Pyranose oxidase can use glucose as its substrate to generate hydrogen peroxide. White rot fungi, which degrade diverse recalcitrant compounds, contain lignin-degrading enzymes, and lignin peroxidase and manganese peroxidase require hydrogen peroxide for their enzymatic reactions. In this study, we isolated a cDNA fragment of pyranose oxidase from Phlebia tremellosa using PCR and examined its expression under the degradation conditions of diethylphthalate (DEP). Pyranose oxidase expression was enhanced up to 30% by the addition of DEP, and this result supports the possible involvement of pyranose oxidase in the degradation of recalcitrant compounds.

• Korean Journal of Microbiology
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• v.46 no.1
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• pp.93-95
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• 2010

White rot fungi which have lignin degrading enzymes show high degrading activity to diverse recalcitrant compounds such as polycyclic aromatic compounds, dyes, explosives and endocrine disrupting chemicals. We have examined decolorizing activity of dyes by Phlebia tremellosa and two transformants which had genetically transformed using laccase or manganese peroxidase (MnP) gene. In case of methyl green, wild type strain showed 50% decolorization while laccase transformant (TF2-1) and MnP transformant (T5) showed more than 90% decolorization on day 3. Remazol brilliant blue R(RBBR) was decolorized up to 85% by two transformants while the wild type showed 67% decolorization on day 3. Transformants TF2-1 and T5 both showed increased laccase and MnP activity respectively during the whole growing phase.

• Korean Journal of Microbiology
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• v.43 no.2
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• pp.147-149
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• 2007

White-rot fungi which degrade lignin can also degrade diverse recalcitrant compounds such as polymeric dyes, explosives, pesticides, and endocrine disrupting chemicals. Lignin degrading enzymes are involved in the degradation reactions, and introduction of foreign genes into a white-rot fungus is required in order to increase the degrading capacity. Genetic transformation experiment has been carried out in Irpex lacteus and Phlebia tremellosa to an antibiotic resistance. The transformation yields were 50-70 transformants/${\mu}g$ DNA and 15-25 transformants/${\mu}g$ DNA in I. lacteus and P. tremellosa, respectively. The stable replication of the plasmid was confirmed by PCR using the plasmid-specific primers, and many mutants were generated during this integration in both fungi.

• Korean Journal of Microbiology
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• v.45 no.1
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• pp.82-85
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• 2009

Endocrine disrupting chemicals (EDCs) disturb animal hormonal system even at very low concentrations, and finally give harmful effects to human through the food web. A white rot fungus Phlebia tremellosa isolated in Korea, was reported to have good degrading activity against the endocrine disrupting phthalates. However, this fungus has very low manganese peroxidase (MnP) activity under various culture conditions while laccase and lignin peroxidase activities were high. We have isolated an MnP cDNA from Trametes versicolor which was involved in the degradation of EDCs, and constructed an MnP expression vector to use in the genetic transformation of P. tremellosa in order to get higher MnP producing strains. Many transformants had integrated expression vector in their chromosomal DNAs, and showed increased MnP activity. One of two transformants showed increased degradation of 4 EDCs (70${\sim}$88%) than the wild type (30${\sim}$45% degradation rates), and showed twice better removal of estrogenic activities generated by the EDCs than the wild type.

• Korean Journal of Microbiology
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• v.44 no.1
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• pp.10-13
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• 2008

Endocrine disrupting chemicals (EDCs) are hard to be degraded in nature, and are also accumulated in diverse organisms. They finally give negative effects to human through the food web. White rot fungi which have lignin-degrading enzymes have high potentials for degradation of recalcitrant compounds, and a white rot fungus, Phlebia tremellosa, isolated in Korea show good degrading activity against the endocrine disrupting phthalates. We have isolated a laccase cDNA which was involved in the degradation of EDCs, and constructed a laccase expression vector to use in the genetic transformation of P. tremellosa. The expression vector was stably integrated into the chromosomal DNAs and showed increased laccase activity in transformants. One of transformants showed not only increased degradation of several EDCs but also faster estrogenic decreasing activities generated by the EDCs.

• Korean Journal of Microbiology
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• v.44 no.3
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• pp.199-202
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• 2008

A white rot fungus Irpex lacteus produced lignin degrading enzymes, which showed degrading activity against various recalcitrant compounds. However, laccase, one of the lignin degrading enzymes, was too low to be assayed by spectrophotometry using o-tolidine as the chromogenic substrate in this fungus under various culture conditions. A laccase expression vector was constructed using a cDNA from Phlebia tremellosa with the constitutively expressed promoter of glyceraldehydes-3-phosphate dehydrogenase gene, and introduced into I. lacteus by the restriction enzyme mediated integration transformation through the protoplast-$CaCl_2$ procedure. Two transformants showed highly increased laccase activities at the early growth phase in the minimal liquid medium, and they not only degraded bisphenol A, a notorious endocrine disrupting chemical, but also removed the estrogenic activity effectively.