微波条件下LiCl/DMAc溶解稻秆纤维素制备还原糖

摘要

Lithium chloride/N, N-dimethyl acetamide (LiCl/DMAc) solvent was used to dissolve straw cellulose assisted by microwave heating, in order to improve the efficiency of enzymatic hydrolysis.Effects of microwave time and density on yields and conversation of reducing sugars were studied. Micromorphology and thermostability of regenerated straw cellulose were characterized by scanning electron microscopy (SEM) and thermal gravimetric analyzer (TG). Through high performance liquid chromatography (HPLC), components in hydrolyzate were further confirmed and their content/concentration was quantitatively analyzed. The results showed that the dissolution of straw cellulose in LiCl/DMAc solvent was promoted due to microwave heating. Compared with original cellulose, the straw treated by microwave-LiCl/DMAc method depolymerized into fragments and thermal decomposition temperature decreased from 290 ℃ to 220 ℃. Conversation of reducing sugar increased from 30. 90％ to 98.67％, under condrtions of microwave power at 385 W for 7 min. HPLC analysis of saccharification products revealed that glucose and xylose were major components in hydrolysate solution, it arrived at 43.74％ and 48.55％ of total reducing sugar.%利用氯化锂/N,N-二甲基乙酰胺(LiCl/DMAc)溶剂体系在微波控制条件下对稻秆纤维素进行溶解预处理以提高纤维素酶解糖化效率.考察了微波时间和微波强度对产糖量及还原糖转化率的影响.通过扫描电镜(SEM)和热重分析仪(TG)对预处理前后稻秆纤维素的微观形貌及热稳定性进行表征,并利用高效液相色谱仪(HPLC)对酶解糖液进行糖成分鉴定和含量分析.结果表明,微波加热能够有效促进LiCl/DMAc对稻秆纤维素的溶解.与原生稻秆相比,经微波-LiCl/DMAc法溶解后再生纤维素出现明显解聚,热分解温度由290 ℃降至220 ℃.在微波功率为385 W、加热溶解时间为7 min时,所得稻秆纤维素还原糖转化率由30.90%上升至98.67%;HPLC谱图表明,糖液中主要成分为葡萄糖和木糖,分别占所得还原糖总量的43.74%和48.55%.