<Original>Microwave Irradiation of Lignocellulosic Materials : IV. Enhancement of Enzymatic Susceptibility of Microwave-irradiated Softwoods

Abstract

Effect, of microwave irradiation on the enzymatic susceptibility of various softwoods was investigated. The pH values of the reaction liquor dropped with increasing temperature to 2.9-3.3 at 230℃, consistent with increase in acidity (0.5-0.85 meq at 230-239℃). Above approximately 180℃, hemicellulose underwent acid-mediated autohydrolysis and became water-soluble yielding a mixture of oligosaccharides and monosaccharides. The composition of water-soluble portion was similar for all wood species tested. The maximum extents of saccharification below 240℃ ranged between 36-62% for softwoods, while those for hardwoods were between 88-93%. The present investigation confirmed that microwave pretreatment enhanced the enzymatic susceptibility of various softwoods. However, further attempt should be needed to give higher values equal to those for hardwoods.