- Purification and Characterization of Laccase from the White Rot Fungus Trametes versicolor
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Moon-Jeong Han , Hyoung-Tae Choi , Hong-Gyu Song
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J. Microbiol. 2005;43(6):555-560.
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DOI: https://doi.org/2290 [pii]
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 Abstract
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Laccase is one of the ligninolytic enzymes of white rot fungus Trametes versicolor 951022, a strain first isolated in Korea. This laccase was purified 209-fold from culture fluid with a yield of 6.2% using ethanol precipitation, DEAE-Sepharose, Phenyl-Sepharose, and Sephadex G-100 chromatography. T. versicolor 951022 excretes a single monomeric laccase showing a high specific activity of 91,443 U/mg for 2,2''-azino-bis-(3-ethylbenzthiazoline-6-sulfonic acid) (ABTS) as a substrate. The enzyme has a molecular mass of approximately 97 kDa as determined by SDS-PAGE, which is larger than those of other laccases reported. It exhibits high enzyme activity over broad pH and temperature ranges with optimum activity at pH 3.0 and a temperature of 50oC. The Km value of the enzyme for substrate ABTS is 12.8 M and its corresponding Vmax value is 8125.4 U/mg. The specific activity and substrate affinity of this laccase are higher than those of other white rot fungi, therefore, it may be potentially useful for industrial purposes.
- Degradation of Phenanthrene by Trametes versicolor and Its Laccase
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Mun-Jung Han , Hyoung-Tae Choi , Hong-Gyu Song
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J. Microbiol. 2004;42(2):94-98.
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DOI: https://doi.org/2039 [pii]
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Phenanthrene is a three-ring polycyclic aromatic hydrocarbon and commonly found as a pollutant in various environments. Degradation of phenanthrene by white rot fungus Trametes versicolor 951022 and its laccase, isolated in Korea, was investigated. After 36 h of incubation, about 46% and 65% of 100 mg/l of phenanthrene added in shaken and static fungal cultures were removed, respectively. Phenanthrene degradation was maximal at pH 6 and the optimal temperature for phenanthrene removal was 30^oC. Although the removal percentage of phenanthrene was highest (76.7%) at 10 mg/ l of phenanthrene concentration, the transformation rate was maximal (0.82 mg/h) at 100 mg/L of phenanthrene concentration in the fungal culture. When the purified laccase of T. versicolor 951022 reacted with phenanthrene, phenanthrene was not transformed. The addition of redox mediator, 2,2'- azino-bis-(3-ethylbenzthiazoline-6-sulfonic acid) (ABTS) or 1-hydroxybenzotriazole (HBT) to the reaction mixture increased oxidation of phenanthrene by laccase about 40% and 30%, respectively.
- Cloning of Genomic DNAs of Trametes versicolor Acting as Autonomously Replicating Sequences in Saccharomyces cerevisiae
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Sora An , Kyoung Phil Park , Hyoung-Tae Choi , Kyu-Joong Kim , Kyunghoon Kim
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J. Microbiol. 2002;40(3):245-247.
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A genomic DNA library of the fungus Trametes versicolor was constructed in a yeast integration vector which contains the URA3 gene of the budding yeast Saccharomyces cerevisiae and the gene responsible for hygromycin B resistance, and fragments acting as autonomously replicating sequences (ARSes) in the budding yeast were identified from the genomic DNA library. Sixteen recombinant plasmids from the library transformed the budding yeast Saccharomyces cerevisiae to Ura^+ at high frequencies. They were maintained stably under selective conditions, but were gradually lost from yeast cells at different rates under nonselective conditions, indicating that they contain eukaryotic origins of DNA replication and exist as extrachromosomal plasmids. Base sequences of four ARS DNAs among the 16 cloned fragments revealed that all of the four contain at least one 11 bp [(A/T)TTTA(T/C)(A/G)TTT(A/T)] consensus sequence of the budding yeast ARS.
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