乙酸/乙酸钠调控pH值对杨木预水解液物化性质的影响

Effect of pH control on the physico-chemical properties of poplar prehydrolysate by acetic acid-sodium acetate buffer

采用乙酸/乙酸钠缓冲溶液对杨木木片进行预水解,研究了共轭酸碱调控体系的水合氢离子浓度对预水解液物化性质的影响。结果表明:乙酸/乙酸钠共轭酸碱可以抵抗预水解过程中由于果胶质及半纤维素侧链乙酰基等水解所形成的酸性物质,将预水解体系的pH值维持在一定范围内,在调控半纤维素和木质素降解溶出的同时,一定程度上防止单糖的进一步降解和木质素的缩合。预水解过程中溶入液相中的物质主要以DS的形式存在,但预水解液中大约有20%的木质素是以与聚糖集聚成微粒或胶体的形式存在的,会影响后续糖类的分离与纯化。

The poplar wood chips were prehydrolyzed by acetic acid-sodium acetate buffer and the effect of controlling hydronium ion concentration on the physico-chemical properties of the prehydrolysate was studied. The results showed that the acetic acid-sodium acetate buffer can resist the acids produced by the hydrolysis of the pectin substance and the acetyl in hemicellulose side chain, maintaining the pH of the prehydrolysis system within a certain range, controlling the degradation and dissolution of hemicellulose and lignin to some extent, preventing further degradation of monosaccharide and the condensation reaction of lignin. The substance in the liquid phase mainly existed in the form of DS. However, about 20% of lignin are in the form of colloid or aggregated into particles with oligosaccharide, which will interfere with the separation and purification of oligosaccharide.