摘要
为研究不同温度下Na OH预处理对玉米秸秆纤维结构特性和酶解得率的影响,为确定纤维原料碱法预处理的适宜条件提供理论依据,采用稀Na OH溶液对玉米秸秆分别在60、80、105℃下预处理,测定了预处理前后纤维原料的化学组成和酶解得率,并采用扫描电镜(SEM)、X射线衍射仪(XRD)和傅里叶变换红外光谱仪(IR)对预处理前后玉米秸秆的纤维结构进行了表征。结果表明:Na OH预处理能够有效脱除玉米秸秆中木质素,增加纤维素和半纤维素比例,提高纤维素结晶度,产生的润涨作用导致纤维束状结构疏松。Na OH 80℃预处理1 h后,玉米秸秆中纤维素结晶度达到63.7%,60 h的酶解得率达到71.4%;碱处理温度进一步升高则会充分暴露纤维表面纹孔,同时使纤维素分子内氢键重新形成,容易进一步损失半纤维素,降低纤维素的润涨程度,从而降低酶解效率。80℃条件下碱处理能够有效改善玉米秸秆纤维结构,提高其转化利用效率。
Corn stover biomass is an important source of bioenergy. However, lignin in corn stover profoundly reduces its enzymatic degradation. Here the influences of sodium hydroxide pretreatments under different temperatures（60 ℃, 80 ℃ and 105 ℃） on cellulosic structure characteristics and enzymatic hydrolysis yields of corn stover were investigated. The cellulosic structures of raw and alkali-pretreated corn stover were characterized using Scanning Electron Microscopy（SEM）, X- ray Diffractometer（XRD） and Fourier Transform Infrared Spectrometer（FTIR）. Results showed that alkaline pretreatments of corn stover effectively removed lignin, and increased the ratios of cellulose and hemicellulose and the crystallinity of cellulose, resulting in more porous cellulosic structure. After pretreatments with dilute Na OH solution under 80 ℃ for 1 h, the crystallinity of cellulose of corn stover residues reached to 63.7% and the yield of enzymatic hydrolysis to 71.4% after 60 h. High pretreatment temperature caused exposure of pits on fiber surface and reformation of hydrogen bonds in cellulose molecules, causing further losses of hemicellulose, reduction of cellulose swelling degree and decrease of enzymatic hydrolysis yield.The present findings suggest that alkaline pretreatment under 80 ℃ would be the optimum condition for improving the structural characteristics and facilitating the conversion to saccharides from cellulose.
出处
《农业环境科学学报》
CAS
CSCD
北大核心
2016年第7期1407-1412,共6页
Journal of Agro-Environment Science
基金
辽宁省自然科学基金项目(2014026011)
中央高校基本科研业务费项目(DC201502020407)
关键词
玉米秸秆
NaOH预处理
化学组成
纤维结构
酶水解
corn stover
Na OH pretreatment
chemical composition
cellulosic structure
enzymatic hydrolysis
