Samsung Advanced Institute of Technology, Yongin 446-712, Republic of Korea.
Bioresour Technol. 2011 Oct;102(19):8992-9. doi: 10.1016/j.biortech.2011.06.068. Epub 2011 Jun 23.
Liberation of fermentable sugars from recalcitrant lignocellulosic biomass is one of the key challenges in production of cellulosic ethanol. Here we developed a two-stage pretreatment process using aqueous ammonia and dilute sulfuric acid in a percolation mode to improve production of fermentable sugars from rice straw. Aqueous NH₃ was used in the first stage which removed lignin selectively but left most of cellulose (97%) and hemicellulose (77%). Dilute acid was applied in the second stage which removed most of hemicellulose, partially disrupted the crystalline structure of cellulose, and thus enhanced enzymatic digestibility of cellulose in the solids remaining. Under the optimal pretreatment conditions, the enzymatic hydrolysis yields of the two-stage treated samples were 96.9% and 90.8% with enzyme loadings of 60 and 15FPU/g of glucan, respectively. The overall sugar conversions of cellulose and hemicellulose into glucose and xylose by enzymatic and acid hydrolysis reached 89.0% and 71.7%, respectively.
从木质纤维素生物质中释放可发酵糖是生产纤维素乙醇的关键挑战之一。在这里，我们开发了一种两步预处理工艺，使用氨水溶液和稀硫酸在渗滤模式下，以提高从稻草中生产可发酵糖的效率。在第一阶段使用氨水溶液，可选择性地去除木质素，但保留了大部分纤维素（97%）和半纤维素（77%）。在第二阶段使用稀酸，可去除大部分半纤维素，部分破坏纤维素的结晶结构，从而提高剩余固体中纤维素的酶解可及性。在最佳预处理条件下，两步处理样品的酶水解产率分别为 96.9%和 90.8%，酶用量分别为 60 和 15FPU/g 葡聚糖。通过酶解和酸解，纤维素和半纤维素转化为葡萄糖和木糖的总糖转化率分别达到 89.0%和 71.7%。
