Dept. of Biological Systems Engineering, University of Nebraska-Lincoln, Lincoln, NE 68583, USA.
Biotechnol Prog. 2010 May-Jun;26(3):644-52. doi: 10.1002/btpr.371.
Switchgrass and coastal bermudagrass are promising lignocellulosic feedstocks for bioethanol production. However, pretreatment of lignocelluloses is required to improve production of fermentable sugars from enzymatic hydrolysis. Microwave-based alkali pretreatment of switchgrass and coastal bermudagrass was investigated in this study. Pretreatments were carried out by immersing the biomass in dilute alkali reagents and exposing the slurry to microwave radiation at 250 W for residence times ranging from 5 to 20 min. Simons' stain method was used to quantify changes in biomass porosity as a result of the pretreatment. Pretreatments were evaluated based on yields of total reducing sugars, glucose, and xylose. An evaluation of different alkalis identified sodium hydroxide as the most effective alkali reagent for microwave-based pretreatment of switchgrass and coastal bermudagrass. 82% glucose and 63% xylose yields were achieved for switchgrass and 87% glucose and 59% xylose yields were achieved for coastal bermudagrass following enzymatic hydrolysis of biomass pretreated under optimal conditions. Dielectric properties for dilute sodium hydroxide solutions were measured and compared with solid losses, lignin reduction, and reducing sugar levels in hydrolyzates. Results indicate that dielectric loss tangent of alkali solutions is a potential indicator of the severity of microwave-based pretreatments.
柳枝稷和海滨雀稗是很有前途的木质纤维素生物乙醇生产原料。然而，为了提高酶解过程中可发酵糖的产量，需要对木质纤维素进行预处理。本研究中对柳枝稷和海滨雀稗的微波碱预处理进行了研究。通过将生物质浸泡在稀碱试剂中，并在 250 W 的微波辐射下辐射 5 到 20 分钟来进行预处理。西蒙氏染色法用于定量生物质孔隙率因预处理而发生的变化。根据总还原糖、葡萄糖和木糖的产率来评估预处理。对不同碱的评价表明，氢氧化钠是用于柳枝稷和海滨雀稗微波预处理的最有效碱试剂。在最佳条件下预处理生物质，经酶水解后，柳枝稷的葡萄糖和木糖得率分别为 82%和 63%，海滨雀稗的葡萄糖和木糖得率分别为 87%和 59%。测量了稀氢氧化钠溶液的介电特性，并与水解产物中的固形物损失、木质素减少和还原糖水平进行了比较。结果表明，碱溶液的介电损耗因子是微波预处理强度的潜在指标。
