Many studies have investigated how particle size as a biomass physical feature influences sugar yield exclusively in enzymatic hydrolysis. However, without considering the effects of particle size on biomass preprocessing and pretreatment, it is difficult to select an optimal particle size range for bioethanol production considering the multistep nature of this process. Comprehensive effects of particle size on biomass preprocessing, pretreatment, and enzymatic hydrolysis were evaluated in this study by assessing biomass compositional and morphological features, characterizing biomass crystallinity and enzyme-accessible surface area, and studying hydrolysis sugar yield and its efficiency. Results indicated that submillimeter small particles (0.5, 0.25, and < 0.25 mm) experienced greater pretreatment severity and 5–10% more structural composition removal than their millimeter level counterparts (1–4 mm). Although small particles had about 10% higher enzymatic hydrolysis efficiency, the low pretreatment solid and sugar recoveries neutralized their enzymatic hydrolysis efficiency advantage over large particles. This trade-off suggested that there may exist little value in reducing particle size further under millimeter level, comparable total sugar yield can be achieved by biomass of millimeter particle sizes; in the meanwhile, employing millimeter particle sizes can conserve energy in biomass preprocessing since comminution is highly energy-intensive and costly.

许多研究已经调查了作为生物质物理特征的粒度如何仅在酶水解中影响糖产量。然而，在不考虑粒径对生物质预处理和预处理的影响的情况下，考虑到该过程的多步性质，很难选择用于生物乙醇生产的最佳粒径范围。本研究通过评估生物质组成和形态特征，表征生物质结晶度和酶可及表面积，研究水解糖产量及其效率，评估了粒径对生物质预处理、预处理和酶水解的综合影响。结果表明亚毫米级小颗粒（0.5、0.25 和 < 0. 25 mm) 的预处理严重程度更高，结构成分去除率比毫米级对应物 (1-4 mm) 高 5-10%。尽管小颗粒的酶水解效率高出约 10%，但预处理固体和糖的低回收率抵消了它们相对于大颗粒的酶水解效率优势。这种权衡表明，将粒度进一步降低到毫米级以下可能没有什么价值，通过毫米级粒度的生物质可以实现相当的总糖产量；同时，在生物质预处理过程中，采用毫米粒径可以节省能源，因为粉碎是高度能源密集型且成本高昂的。较低的预处理固体和糖回收率抵消了它们相对于大颗粒的酶水解效率优势。这种权衡表明，将粒度进一步降低到毫米级以下可能没有什么价值，通过毫米级粒度的生物质可以实现相当的总糖产量；同时，在生物质预处理过程中，采用毫米粒径可以节省能源，因为粉碎是高度能源密集型且成本高昂的。较低的预处理固体和糖回收率抵消了它们相对于大颗粒的酶水解效率优势。这种权衡表明，将粒度进一步降低到毫米级以下可能没有什么价值，通过毫米级粒度的生物质可以实现相当的总糖产量；同时，在生物质预处理过程中，采用毫米粒径可以节省能源，因为粉碎是高度能源密集型且成本高昂的。