厌氧消化处理玉米秸秆酶解残渣对木质素的影响研究

Effect of anaerobic digestion on lignin derived from unhydrolyzed solid of corn stover

以秸秆为原料生产燃料乙醇会产生大量富含木质素的酶解残渣,从中可回收木质素,但酶解残渣中的糖类等杂质会影响木质素的高值利用。因此,采用厌氧消化的方法处理玉米秸秆酶解残渣,利用凝胶渗透色谱、热重分析、傅里叶红外光谱以及核磁共振氢谱等手段表征处理前后木质素的结构和化学性质。经厌氧处理后,残渣中糖类含量显著降低而木质素总量基本不变,木质素几乎未降解。厌氧处理前后固体残渣中木质素的结构和热化学性质无明显变化,表明该方法能在去除糖类的同时较好地保留木质素的结构。

Fuel ethanol production from agricultural straw will produce a large amount of unhydrolyzed solids(UHS),which can be used to recover lignin.However,the existence of carbohydrates and other impurities will affect the high-value utilization of lignin.Thus,anaerobic digestion(AD)was employed to treat UHS.The structure and chemical properties of lignin were characterized by gel permeation chromatography,thermogravimetric analysis,fourier infrared spectroscopy,and nuclear magnetic resonance hydrogen spectroscopy.The carbohydrate contents of anaerobically digested solids were significantly reduced compared to UHS,while the total amount of lignin remained almost constant.The lignin was almost undegraded during AD.The results showed that the lignin of UHS and anaerobically digested solids presented similar structures and thermochemical properties,indicating that AD of UHS could preserve lignin structure while removing carbohydrates.