Abstract In the current practice of generating ethanol from corn stover (CS), mostly cellulose is converted into ethanol, and water-soluble carbohydrates (WSCs) and/or hemicellulose fractions are often discarded. This incomplete conversion of fermentable components consequently lowers the final ethanol yield of CS. Normal corn stover (NCS) that is commonly used in the stover-based ethanol production, contains poor amounts of WSCs, and eventually, it is not attractive to conduct a separate extraction of WSCs from NCS. Alternatively, high sugary stover (HSS) could be a promising feedstock system over NCS for particularly its excellent sugar content. This study investigated the effects of converting both water-soluble and structural carbohydrates on ethanol production, by comparing the ethanol yields of HSS and NCS obtained from four high sugary and four normal corn genotypes, respectively. The corn genotypes were cultivated and stovers were harvested at three growth stages of plants, including dough (R4), dent (R5), and maturity (R6) stages. Despite the WSC contents of both types of stovers were found to decrease as the plants moved from R4 to R6 stage, quantities of WSCs in HSS were significantly higher at all stages than the respective WSC contents of NCS. At the R4 stage, the amounts of WSCs ranged from 19.1 to 29.2% in HSS, which varied in NCS between 10.2% and 13.6% at the same stage, and finally reached 10.2–14.9% in HSS and 4.1–5% in NCS at the R6 stage. WSCs of HSS produced a maximum of 14.9 g/L of ethanol at the R4 stage in contrast to only 5.5 g/L of ethanol produced by the WSCs of NCS. Irrespective of the growth stages, the net specific ethanol yields (SEY) of HSS and NCS varied from 149.7 to 204.8 g/kg and 139.6 to 170.1 g/kg, respectively, where stovers harvested at the R4 stage provided the maximum SEY.

中文翻译：

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从三个生长阶段收获的普通和高糖玉米秸秆的水溶性和结构性碳水化合物生产生物乙醇

摘要 在目前从玉米秸秆 (CS) 生产乙醇的实践中，大部分纤维素转化为乙醇，水溶性碳水化合物 (WSC) 和/或半纤维素部分经常被丢弃。可发酵组分的这种不完全转化因此降低了 CS 的最终乙醇产量。通常用于基于秸秆的乙醇生产的普通玉米秸秆 (NCS) 含有少量 WSC，最终，从 NCS 中单独提取 WSC 没有吸引力。或者，高糖秸秆 (HSS) 可能是比 NCS 更有前途的原料系统，因为它的糖含量特别高。本研究调查了水溶性和结构性碳水化合物对乙醇生产的影响，通过比较分别从四种高糖和四种正常玉米基因型中获得的 HSS 和 NCS 的乙醇产量。在植物的三个生长阶段，包括生面团（R4）、凹痕（R5）和成熟（R6）阶段培养玉米基因型并收获秸秆。尽管发现两种类型的秸秆的 WSC 含量随着植物从 R4 阶段移动到 R6 阶段而减少，但 HSS 中 WSC 的数量在所有阶段都显着高于 NCS 各自的 WSC 含量。在 R4 阶段，HSS 中 WSCs 的数量从 19.1% 到 29.2% 不等，在同一阶段 NCS 在 10.2% 到 13.6% 之间变化，最后在 HSS 中达到 10.2-14.9%，在 NCS 中达到 4.1-5% R6阶段。HSS 的 WSC 在 R4 阶段最多产生 14.9 g/L 的乙醇，而 NCS 的 WSC 仅产生 5.5 g/L 的乙醇。