Elementary Research On Factors Influencing The Free Radical Reaction Of Laccase Activation Of Wood And The Production Of Enzyme-bonded Fiberboards

With the increasing concern about the living surroundings and human health, the emissive volatile organic compounds (VOC), especially formaldehyde, during the production or use of wood composites has become the focus of attention. The promising future for wood composites might be the wood-based panels, which are formaldehyde-free and environmentally friendly made by enzyme engineering technology. The experimental materials in this study was composed of commercial laccase and wood which included the sapwood and heart of Chinese Fir (Cunninghamia lanceolata), the heartwood of Szemao Pine (Pinus kesiya var. langbianensis), the sapwood and heart of Lemon-scented Gum (Eucalyptus citriodora), the sapwood of Chinese white poplar (Populus tomentosa ), Beautiful Sweetgum (Liquidambar formosana ) wood. With the help of electron spin resonance (ESR) spectrometry, the laccase-catalyzed oxidization of wood was investigated, which by nature belongs to radical reaction. The production of laccase-bonded fiberboards made from wood fibers of Szemao pine was conducted in vitro. The effects of panel density and laccase activation on the mechanical properties of enzyme-bonded fiberboards were studied.The research results were as follows:(1) The method of detecting reactive oxygen species (ROS) during the laccase-catalyzed oxidation of wood using electron spin resonance (ESR) spin trapping technique was created. Using ethyl acetate as an extract solvent to concentrate PBN (N-tert-butyl-a-phenylnitrone)-ROS spin adduct from the aqueous supernatant and to eliminate the water's negative effect on ESR detection, compared with other methods to detect free radicals our method is feasible.