Functionalisation of organosolv lignin by enzymatic demethylation for bioadhesive formulation

Bio-based adhesives offer a sustainable alternative to formaldehyde-based adhesives, which is the most common product applied in wood-based panel manufacturing. Despite undeniable interest lignin as bulk chemical for synthesis of bio-based main problem its low reactivity. Therefore, it crucial study techniques increase their reactivity, such demethylation. One parameters monitor success demethylation methanol concentration measured reaction medium and complementing these results with use non-quantitative analyses FT-IR, MALDI-ToF SEC. In order maximize action enzyme, preliminary screening was performed laccases different redox potentials, were added organosolv form purified enzymes cocktails. Trametes versicolor laccase selected best candidate lignin, released 107 mg/L. Based on results, affecting both enzyme enzyme-substrate interaction evaluated. Optimal working conditions strongly defined by surfactants that enhanced solubility (Tween-80) mediators favored catalysis participate directly catalytic cycle (HBT). However, also observed factors pH, temperature aeration have direct impact enzymatic lignin. Considering operational variables allowed better values, amount increased 363 mg/L, means an improvement 239 %. These supported molecular weight SEC analysis reduction intensity FT-IR bands related methyl/methoxyl groups.