Study On Hemicellulase/Laccase Treat Bamboo Technique And Self-bonding Particleboard Preparation

Bamboo, as important biomass resources, has favorable environment for enzyme processing. Hemicellulase and laccase was respectively used to depredating hemicellulose and lignin. Process parameters for bamboo particleboard were probed in two different conditions:water-bath processing and dry spraying processing. The suitable coordination treatment conditions were surveyed for bamboo particleboard under improved hot-pressing process. Chemical structures in different stages were analyzed adopting FTIR spectroscopy and the self-bonding mechanisms were summed up. The research provides theoretical guidance for enzyme application and developing of self-bonding bamboo production(1) Adopting water bath pretreatment methods, bamboo self-bonding particleboards were preparation. Study shows:hemicellulase dosage and laccase dosage have significant effects on the boards performance. The optimized pretreatment parameters were defined on experiment as follow: pretreatment temperature 60℃, hemicellulase dosage 500U/g, buffer solution pH=8～9, length of time 15 min, laccase dosage 34U/g, buffer solution pH=3～4, length of time 120 min.(2) Adopting dry spaying pretreatment methods, bamboo self-bonding particleboards were preparation. Study shows:enzyme dosage, buffer solution pH and length of time have significant effects on the boards performance. The optimized pretreatment parameters were defined as follow:pretreatment temperature 60～70℃, hemicellulase dosage 500U/g, buffer solution pH=9, length of time 30 min, laccase dosage 34U/g, buffer solution pH=4, length of time 60 min.(3) Adopt more stages hot-pressing curve, bamboo self-bonding particleboards were preparation. The study has shown:the moisture content of the slab early has notable effect on self-bonding properties. The optimized pretreatment parameters were defined as follow:the moisture content of the slab early about 20%, hot-pressing pressure about 3MPa, hot-pressing temperature 180℃, hot-pressing time(main the holding time) about 18min.(4) Particle size has different levels of importance on self-bonding properties. The study has shown that 4～16 orders particle units were optimal. Tiny particles are propitious to MOR, wafers are difficult to fully contact with each other. (5) Infrared spectral analysis showed:hemicellulase mainly reacts on C-O-C bonding of pyranose and a small amount lipids in water bath processing.. Laccase mainly reacts on phenolic hydroxyl group formating free phenolic. The hydroxyl group changing into the acylamide is important to self-bonding. Hemicellulase mainly reacts on C-O-C bonding of pyranose and lipids to formatting C=O, free sugar and small molecules lipid. Laccase mainly reacts on skeleton of benzene and phenolic hydroxyl group formating unsaturated hydrocarbon and free phenolic. Active functional groups and small-molecules chemical composition are prone to polycondensation and esterification, which are important to self-bonding.