Abstract：
This study proposed a two-stage pressurized microwave hydrothermal treatment with a catalyst, followed by enzymatic saccharification, as a pretreatment method for efficiently converting cellulose and hemicellulose from rice straw into glucose and xylose. The use of various inorganic salts and dilute sulfuric acid as catalysts enhances sugar production. Using 1 wt% sulfuric acid as a catalyst at 150 °C for 5 min for the first-stage and then 180 °C for 5 min for the second-stage yielded the highest sugar production from rice straw compared with other inorganic salts tested. The filtrate and enzymatic saccharification solution contained a total sugar of 0.434 g/g-untreated rice straw (i.e. 0.302 g-glucose/g-untreated rice straw and 0.132 g-xylose/g-untreated rice straw). When inorganic salts such as NaCl, MgCl2, CaCl2, and FeCl3 were used as catalysts, the highest sugar yield of 0.414 g/g-untreated rice straw (i.e. 0.310 g-glucose/g-untreated rice straw and 0.104 g-xylose/g-untreated rice straw) was obtained when using 1 wt% FeCl3 at 170 °C for 5 min in the first-stage and 190 °C for 5 min in the second-stage, with a value close to that of 1 wt% sulfuric acid. These findings suggest that two-stage treatment with a catalyst is a suitable pretreatment method for the production of glucose and xylose from rice straw owing to the different hydrolysis temperatures of cellulose and hemicellulose.
摘要：
本研究提出了用催化剂进行两级加压微波水热处理，然后是酶促糖化，作为一种有效地将稻草中的纤维素和半纤维素转化为葡萄糖和木糖的预处理方法。使用各种无机盐和稀硫酸作为催化剂可提高糖的产量。第一阶段使用1wt％的硫酸作为催化剂，在150°C下5分钟，然后在第二阶段使用180°C下5分钟，与其他测试的无机盐相比，稻草的糖产量最高。滤液和酶促糖化溶液含有0.434g/g未处理的稻草的总糖(即0.302g-葡萄糖/g-未处理的稻草和0.132g-木糖/g-未处理的稻草)。当无机盐如NaCl时，使用MgCl2、CaCl2和FeCl3作为催化剂，当在170°C下使用1wt％的FeCl3时，获得了0.414g/g未经处理的稻草（即0.310g-葡萄糖/g-未经处理的稻草和0.104g-木糖/g-未经处理的稻草）的最高糖产率。第一阶段5分钟，第二阶段190°C5分钟，值接近1重量%的硫酸。这些发现表明，由于纤维素和半纤维素的水解温度不同，用催化剂进行两阶段处理是由稻草生产葡萄糖和木糖的合适预处理方法。
