Biochemical characterization of a novel laccase from the basidiomycete fungus Cerrena sp. WR1.
This study reports a new white-rot fungus Cerrena sp. WR1, identified based on an 18S rDNA sequence, which can secrete extracellular forms of laccase with a maximal activity reaching 202 000 U l⁻¹ in a 5-l fermenter. A laccase protein, designated Lcc3, was purified and shown to be N-linked glycosylated by PNGase F and liquid chromatography tandem mass spectrometry analyses. The respective full-length cDNA gene (lcc3) of the Lcc3 protein was obtained using polymerase chain reaction-based methods. Kinetic studies showed that the K(m) and k(cat) of the native Lcc3 were 3.27 μM and 934.6 s⁻¹ for 2,2'-Azino-bis-(3-ethylbenzthiazoline-6-sulfonic acid), 849.1 μM and 147.9 s⁻¹ for guaiacol, 392.7 μM and 109.2 s⁻¹ for 2,6-dimethoxyphenol, and 881 μM and 115.5 s⁻¹ for catechol, respectively. The T(m) of Lcc3 was determined at 73.9°C and it showed a long t(½) (120 min) at 50°C. The laccase was highly ethanol resistant, with 80% of its original activity was detected when incubated in 25% ethanol for 14 days. Furthermore, crude enzyme broth or Lcc3 could degrade lignin in kraft paper (26.5%), and showed high decoloration efficiency (90%) on synthetic dye Remazol Brilliant Blue R. Together, these data demonstrate that Cerrena sp. WR1 Lcc3 possesses novel biochemical and kinetic properties that may aid its application in industry.
Agricultural Biotechnology Research Center,  Academia Sinica, Taipei 115,  Taiwan, ROC.
Sheng-Chung
SC
Chen
Po-Hung
PH
Wu
Yu-Chang
YC
Su
Tuan-Nan
TN
Wen
Yun-Syuan
YS
Wei
Nai-Chen
NC
Wang
Chih-An
CA
Hsu
Andrew H-J
AH
Wang
Lie-Fen
LF
Shyur
D000880:Anthraquinones / Q000378:metabolism; D001487:Basidiomycota / Q000737:chemistry / Q000201:enzymology* / Q000235:genetics; D003001:Cloning, Molecular; D004396:Coloring Agents / Q000378:metabolism; D018076:DNA, Complementary / Q000235:genetics; D004271:DNA, Fungal / Q000235:genetics; D004795:Enzyme Stability; D006031:Glycosylation; D042845:Laccase / Q000737:chemistry* / Q000235:genetics* / Q000302:isolation & purification / Q000378:metabolism*; D008031:Lignin / Q000378:metabolism; D010802:Phylogeny
D000880:Anthraquinones; D004396:Coloring Agents; D018076:DNA, Complementary; D004271:DNA, Fungal; D008031:Lignin; D042845:Laccase