离子液体[Hmim][CF_3SO_3]在木质素及其模型化合物生物降解中的应用

研究了在室温下,离子液体Hmim]CF_3SO_3]溶解木质素及其模型化合物后,与酶液在小分子有机酸作用下形成的三元液相平衡体系,及在此体系中进行酶促反应的过程。结果表明:小分子有机酸使水-离子液体形成的两相转化为均相的主要贡献是由羧基提供的,Hmim]CF_3SO_3]在溶解木质素后依旧保留与有机酸和水形成三元相平衡体系的能力;以酶液作为水相,以溶解了木质素的离子液体作为疏水相,甲酸的掺入在起到平衡水相和疏水相的同时也作为木质素降解酶反应过程中的自由基稳定剂;在三元液相体系的反应中,离子液体引起酶的部分失活;随着反应的进行,碱木质素和木质素脱氢聚合物(DHPs)的降解率分别为56.5%和66.5%,甲氧基分别降低了46.7%和45.3%,生成的酚类化合物分别为204.7和207.0 mg/L,甲酸分别消耗了0.57和0.76 g。DHPs在降解过程中,由于甲酸的过度消耗导致了平衡体系的解体。

Application of Ionic Liquid [ Hmim] [ CF3 SO3] in Biodegradation of Lignin & Lignin Model Compounds

The ternary liquid-liquid equilibrium system composed of ionic liquid Hmim] CF3 SO3 ] which dissolved lignin with enzyme solution and the organic acid was investigated in present study. The enzymatic reactions in the system were also studied. The transformation from water-ionic two phase system to homogeneous system should be attributed to the function of carboxylic acid groups in small molecule organic acids. Hmim] CF3 SO3 ] with dissolved lignin could also compose the ternary system with water and organic acid. In the degradation reaction, formic acid played two roles in balancing the hydrophobic phase ( Hmim] CF3SO3]with dissolved lignin), and aqueous phase (enzyme solution), and acting as radical stabilizer for lignin degrading enzymatic reaction. The degradation rates of alkali lignin and dehydrogenation polymers of lignin ( DHPs) were 56. 5% and 66. 5%, and the content of methoxyl group decreased by 46. 7% and 45. 3%, respectively. The generated phenolic compounds were 204. 7 and 207. 0 mg/L, and the formic acid consumption were 0. 57 and 0. 76 g, respectively. In the DHPs degradation process, the ternary equilibrium was disintegrated due to the excessive consumption of formic acid.