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Protection of wood from microorganisms by laccase-catalyzed iodination.

Applied and environmental microbiology (2012-08-07)
M Schubert, J Engel, L Thöny-Meyer, F W M R Schwarze, J Ihssen
ABSTRACT

In the present work, Norway spruce wood (Picea abies L.) was reacted with a commercial Trametes versicolor laccase in the presence of potassium iodide salt or the phenolic compounds thymol and isoeugenol to impart an antimicrobial property to the wood surface. In order to assess the efficacy of the wood treatment, a leaching of the iodinated and polymerized wood and two biotests including bacteria, a yeast, blue stain fungi, and wood decay fungi were performed. After laccase-catalyzed oxidation of the phenols, the antimicrobial effect was significantly reduced. In contrast, the enzymatic oxidation of iodide (I(-)) to iodine (I(2)) in the presence of wood led to an enhanced resistance of the wood surface against all microorganisms, even after exposure to leaching. The efficiency of the enzymatic wood iodination was comparable to that of a chemical wood preservative, VP 7/260a. The modification of the lignocellulose by the laccase-catalyzed iodination was assessed by the Fourier transform infrared spectroscopy-attenuated total reflectance (FTIR-ATR) technique. The intensities of the selected lignin-associated bands and carbohydrate reference bands were analyzed, and the results indicated a structural change in the lignin matrix. The results suggest that the laccase-catalyzed iodination of the wood surface presents an efficient and ecofriendly method for wood protection.

MATERIALS
Product Number
Brand
Product Description

Sigma-Aldrich
Gold etchant, standard
Sigma-Aldrich
Potassium iodide, puriss. p.a., reag. ISO, reag. Ph. Eur., ≥99.0%
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Potassium iodide, ACS reagent, ≥99.0%
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Potassium iodide, suitable for plant cell culture
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Potassium iodide, AnhydroBeads, −10 mesh, 99.998% trace metals basis
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Potassium iodide, ≥99.99% trace metals basis
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Potassium iodide, BioXtra, ≥99.0%
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Potassium iodide, BioUltra, ≥99.5% (AT)
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Potassium iodide, tested according to Ph. Eur.
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Potassium iodide, ReagentPlus®, 99%
Sigma-Aldrich
Potassium iodide, puriss., meets analytical specification of Ph. Eur. BP, USP, 99.0-100.5% (calc. to the dried substance)