Trametes villosa

Zille A, B Gdrnacka, A Rehorek, A Cavaco-Paulo (2005) Degradation of azo dyes by Trametes villosa laccase over long periods of oxidative conditions. Appl Environ Microbiol 71 6711-6718. 

Xu F, Palmer AE, Yaver DS, Berka RM, Gambetta GA, Brown SH, Solomon El. 1999. Targeted mutations in a Trametes villosa laccase. J Biol Chem 274 12372-12375. 

In Phanerochaete flavido-alba, an induction of ligninolytic activities that was ascribed to phenolic compounds was evidenced [69]. Phenols have also been shown to have an important role as redox mediators for dye degradation with laccases from Pycnoporus cinnabarinus and Trametes villosa, and they resulted to be necessary to degrade a strongly recalcitrant azo dye, the Reactive Black 5 [70]. 

Barsberg and Hassingboe (2003) noted that the use of enzymes for surface activation of fibres for board production can produce highly variable results and that the reasons for this are not understood. In order to further understand the process, they treated TMP fibres with a laccase from Trametes villosa for 1 hour and dried the fibres. A control set of fibres was subjected to an identical protocol, but with no enzyme present. Air-laid fibre mats were produced from the fibres, which were then hot-pressed to form 3 mm thickness boards. Varying amounts of wax were sprayed on to the fibres prior to board production. Both the MOE and the MOR of the composites increased with board density. Boards produced from enzyme-treated or control fibres exhibited no difference in MOE, but the MOR of boards formed from enzyme-treated fibres was higher above a density of 800 kg m . Wax addition resulted in a decrease in mechanical properties. At a board density of c. 930 kg m , the MOR was of the order of 23 MPa and the MOE 11 GPa. 

TABLE 9. Oxidation of X-substituted benzyl alcohols with Trametes villosa laccase and R2NO—H mediators in buffered (pH = 4.5) water solution at 25 °C. Comparison of p (vs. independently generated in MeCN solution at 25 °C... 

The most profitable is certainly the use of laccase (Lc) with TEMPO. It enables the almost quantitative conversion of primary benzylic and allylic alcohols to aldehydes without overoxidation under mild conditions (Table 14, entries 1 and 2), that is, 25 °C and pH = 4.5 in the presence of atmospheric O2, for a reaction time of 24 h. The successful enzyme is the one obtained from the fungus Trametes villosa. 

TABLE 15. Aerobic oxidations with Trametes villosa laccase (Lc) and R2NOH mediators ... 

Figure 2.25. Transformation of catechol (0.1 M) in binary and ternary systems (A) Catechol removal by increasing concentrations of birnessite (B) catechol removal by increasing activities of Trametes villosa laccase (C) catechol removal by T. villosa laccase (950katalml 1) and birnessite (lmgml ) applied together (D) distribution of radioactivity after the incubation of 14C-labeled catechol with T. villosa laccase (950katalml ) and birnessite (lmgml-1).The reactions were carried out in 0.5% NaCl for 24h at 25°C. Reprinted from Ahn, M.-Y., Martinez, C. E., Archibald, D. D., Zimmerman, A. R., Bollag, J.-M., and Dec, J. (2006). Transformation of catechol in the presence of a laccase and birnessite. Soil Biol. Biochem. 38,1015-1020, with permission from Elsevier.

Direct electron transfer-a favorite electron route for cellobiose dehydrogenase (CDH) from Trametes villosa. Comparison with CDH from Phanerochaete chrysosporium. Langmuir, 22 (25), 10801-10806. 

In 1996 it was shown that by using ABTS as a mediator, laccase from Trametes versicolor was able to catalyze the aerobic oxidation of a series of benzylic alcohols to the corresponding benzaldehydes 46). Subsequently, Galli, and co-workers found that the stable N-oxy radical, 2,2,6,6-tetramethyl-piperidinyl-l-oxy (TEMPO, Fig. 4) in combination with laccase from Trametes villosa, catalyzes the aerobic oxidation of primary benzylic alcohols 47). The selective oxidation of the primary alcohol moiety in carbohydrates had been previously reported in two patents 48,49). 

All chemicals were purchased from Aldrich Co., Milwaukee, WI, and used as received, except for p-dioxane and laccase. p-Dioxane was freshly distilled over NaBH4 prior to using it for lignin isolation experiments. The laccase was NS51002 isolated from Trametes villosa and was donated by Novozymes Biotech, Franklinton, NC. 

The titration endpoint is determined by the color change of the analyte solution from a light yellow to a deep purple. The catalytic activity of the laccase is substantially increased at higher temperature and in the presence of the copolymer (Table 3, vials 1 and 2 vs. vial 3). The enzyme is not active without a mediator, Table 3, vial 4. It should be also noted that the conversion yields achieved with the enzyme/linear-dendritic copolymer complex are comparable to those reported previously for the same non-phenolic conqmund and Trametes villosa laccase also in combination with HBT (18). 

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