Steam pretreatment conditions that are typically used to enhance wood derived pellet durability are usually less severe than those used to enhance the enzymatic hydrolysis of woody substrates. In the work reported here steam treated softwoods were used to make pellets and their robustness and subsequent ease of enzymatic hydrolysis were assessed. Although pre-steaming enhanced the durability of pellets it decreased the ease of enzymatic hydrolysis when compared to non-pelletised, pretreated softwoods. However, subsequent mechanical disintegration of the pellets resulted in comparable hydrolysis yields. Transmission Electron Microscopy (TEM) observations suggested that steaming resulted in lignin redistribution which enhanced pellet durability. However, as pelletisation had not changed the lignin distribution within the cell wall subsequent, mild, mechanical disintegration resulted in a softwood substrate that could be as readily hydrolyzed as the non-pelletised feedstock. The addition of lignosulfonates prior to pelletisation substantially enhanced pellet durability with the beneficial effects on subsequent cellulose hydrolysis. This was likely due to the lignosulfonates acting as a surfactant and decreasing the unproductive binding of enzymes to the lignin.

中文翻译：

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预蒸和木质素分布对木质颗粒坚固性的影响以及后续酶介导的纤维素水解的难易程度

通常用于增强木材衍生的颗粒耐久性的蒸汽预处理条件通常不如用于增强木质底物的酶促水解的条件严格。在这里报道的工作中，使用蒸汽处理过的软木制成颗粒，并评估了其坚固性和随后的酶促水解程度。尽管预蒸煮提高了颗粒的耐用性，但与未造粒的预处理软木相比，它降低了酶促水解的难度。然而，随后的粒料机械崩解导致相当的水解产率。透射电子显微镜（TEM）的观察结果表明，蒸煮导致木质素重新分布，从而增强了颗粒的耐久性。但是，由于制粒并没有改变木质素在细胞壁内的分布，因此，机械崩解导致软木基材与未造粒的原料一样容易水解。在造粒之前添加木质素磺酸盐显着提高了粒料的耐久性，并对随后的纤维素水解产生了有益的影响。这可能是由于木质素磺酸盐充当表面活性剂并减少了酶与木质素的非生产性结合。