Selig Michael J, Viamajala Sridhar, Decker Stephen R, Tucker Melvin P, Himmel Michael E, Vinzant Todd B
National Renewable Energy Laboratory, 1617 Cole Boulevard, Golden, Colorado 80401, USA.
Biotechnol Prog. 2007 Nov-Dec;23(6):1333-9. doi: 10.1021/bp0702018. Epub 2007 Oct 31.
Electron microscopy of lignocellulosic biomass following high-temperature pretreatment revealed the presence of spherical formations on the surface of the residual biomass. The hypothesis that these droplet formations are composed of lignins and possible lignin carbohydrate complexes is being explored. Experiments were conducted to better understand the formation of these "lignin" droplets and the possible implications they might have on the enzymatic saccharification of pretreated biomass. It was demonstrated that these droplets are produced from corn stover during pretreatment under neutral and acidic pH at and above 130 degrees C, and that they can deposit back onto the surface of residual biomass. The deposition of droplets produced under certain pretreatment conditions (acidic pH; T > 150 degrees C) and captured onto pure cellulose was shown to have a negative effect (5-20%) on the enzymatic saccharification of this substrate. It was noted that droplet density (per unit area) was greater and droplet size more variable under conditions where the greatest impact on enzymatic cellulose conversion was observed. These results indicate that this phenomenon has the potential to adversely affect the efficiency of enzymatic conversion in a lignocellulosic biorefinery.
对经过高温预处理的木质纤维素生物质进行电子显微镜观察，发现残余生物质表面存在球形结构。目前正在探究这些液滴状结构由木质素以及可能的木质素碳水化合物复合物组成这一假设。开展了相关实验，以更好地了解这些“木质素”液滴的形成过程以及它们对预处理生物质酶解糖化可能产生的影响。结果表明，这些液滴是在130摄氏度及以上的中性和酸性pH条件下预处理玉米秸秆时产生的，并且它们会重新沉积到残余生物质表面。在特定预处理条件下（酸性pH；温度>150摄氏度）产生并附着在纯纤维素上的液滴沉积，已被证明对该底物的酶解糖化有负面影响（5%-20%）。值得注意的是，在观察到对酶促纤维素转化影响最大的条件下，液滴密度（每单位面积）更大，液滴大小的变化也更多。这些结果表明，这种现象有可能对木质纤维素生物精炼厂中的酶促转化效率产生不利影响。
