香菇菌糠中木质纤维素的挤压降解及结构表征

Extrusion Degradation and Structural Characterization of Lignocellulose in Spent Lentinus edodes Substrate

为开发香菇(Lentinus edodes)菌糠的新型加工处理方式,促进其高效转化利用,以香菇菌糠为研究对象,采用范式抽提法、傅里叶变换红外光谱法、X-射线衍射法和光学显微成像对经挤压处理香菇菌糠的木质纤维素含量、木质纤维素官能团、纤维素相对结晶度和纤维形态变化进行分析。结果表明,香菇菌糠经过挤压处理后木质纤维素各组分均有不同程度减少,40%水分挤压和50%水分挤压后木质纤维素含量分别降低了13.863%、11.264%,纤维素含量分别降低了19.003%、16.630%,综纤维素含量分别降低了17.357%、11.343%,木质素含量分别降低了6.574%、11.099%,纤维素相比半纤维素、木质素呈现出更快的降解速度;与50%水分挤压相比,40%水分挤压对半纤维素、综纤维素的降解作用更显著,降解率分别提高了12.131%、6.783%。傅里叶变换红外光谱显示,木质纤维素的红外光谱特征官能团主要吸收峰的位置未发生改变,但吸收峰特征及强度发生变化,表明挤压处理对香菇菌糠中木质纤维素各组分有降解作用,其中半纤维素在低水分条件下更易发生降解,与木质纤维素各组分的挤压降解规律一致。挤压前后的香菇菌糠均具有典型的纤维素X射线衍射特征,挤压后纤维素结晶区被破坏,40%水分挤压和50%水分挤压后纤维素相对结晶度分别降低了21.10%、18.00%。纤维长度、宽度及长宽比呈现出降低趋势,经显微镜观察,挤压后香菇菌糠纤维壁及内腔进一步遭到破坏,膨松状态片状结构明显增多增大。因此,挤压处理可有效降解香菇菌糠木质纤维素,破坏其生物质结构,使得红外光谱吸收峰、纤维素结晶度及纤维形态发生改变,其中,40%水分挤压的降解作用更佳。

In order to develop a new processing method of spent Lentinus edodes substrate and promote its efficient conversion and utilization,spent Lentinus edodes substrate was taken as the material,and the lignocellulose content,lignocellulose functional groups,relative crystallinity of cellulose and fiber morphology of spent Lentinus edodes substrate after extrusion treatment were analyzed by Van Soest method,FTIR,X-ray diffraction method and optical microscopic imaging.Results showed that the degradation degree of lignocellulose components was different after extrusion treatment.After the 40%water extrusion and 50%water extrusion,the lignocellulose content decreased by 13.863%and 11.264%respectively,the cellulose content decreased by 19.003%and 16.630%respectively,the holocellulose content decreased by 17.357%and 11.343%respectively,and the lignin content decreased by 6.574%and 11.099%respectively.The cellulose showed a faster degradation rate than hemicellulose and lignin.Compared with 50%water extrusion,the 40%water extrusion had more significant degradation effect on hemicellulose and holocellulose.The degradation rates were increased by 12.131%and 6.783%,respectively.FTIR showed that the main absorption peaks position of the lignocellulose infrared spectral characteristic functional groups did not change,but the characteristics and intensity changed.It indicated that the extrusion treatment had a degradation effect on the components of lignocellulose,and the hemicellulose was more likely to degrade under low moisture conditions,which was consistent with the extrusion degradation of lignocellulose components.The spent Lentinus edodes substrate before and after extrusion had typical cellulose X-ray diffraction characteristics,the crystalline region of cellulose was destroyed after extrusion,and the relative crystallinity of cellulose decreased by 21.10%and 18.00%after the 40%water extrusion and 50%water extrusion,respectively.The fiber length,width and length-width ratio showed a decreasing trend.Observed by the microscope,the cellulose wall and inner lumen were further destroyed after extrusion,and the sheet structure of bulky state increased significantly.Therefore,the extrusion treatment could effectively degrade the lignocellulose of spent Lentinus edodes substrate,destroy its biomass structure,and change the infrared spectrum absorption peak,cellulose crystallinity and fiber morphology.Among them,the 40%water extrusion was better in degradation effect.