School of Chemical and Biomolecular Engineering, Georgia Institute of Technology, Atlanta, GA 30332-0100, USA.
Biotechnol Prog. 2013 Jul-Aug;29(4):909-16. doi: 10.1002/btpr.1751. Epub 2013 Jun 8.
Lignocellulosic biomass is the most promising feedstock for biofuels production. To enhance the efficiency of enzymatic hydrolysis, lignocellulosics needs to be pretreated to lower their recalcitrance. SO(2) -catalyzed steam explosion is an efficient and relatively cost-efficient pretreatment method for softwood. This work investigates the effects of steam explosion severity on the digestibility, accessibility, and crystallinity of Loblolly pine. Higher severity was found to increase the accessibility of the feedstock while also promoting nonselective degradation of carbohydrates. The adsorption behavior of Celluclast® enzymes on steam-exploded Loblolly pine (SELP) can be described by a Langmuir isotherm. Cellulose crystallinity was found to first increase and then decrease with increasing pretreatment severity. A linear relationship between initial hydrolysis rates and crystallinity index (CrI) of pretreated Loblolly pine was found; moreover, a strong correlation between X-ray diffraction intensities and initial rates was confirmed. The findings demonstrate the significance of CrI in enzymatic hydrolysis of pretreated lignocellulosic biomass.
木质纤维素生物质是生产生物燃料最有前途的原料。为了提高酶水解的效率，木质纤维素需要进行预处理以降低其抗降解性。SO2-催化的蒸汽爆破是一种高效且相对具有成本效益的预处理方法，适用于软木。本工作研究了蒸汽爆破强度对火炬松可消化性、可及性和结晶度的影响。较高的强度被发现可以提高原料的可及性，同时促进碳水化合物的非选择性降解。纤维素酶在蒸汽爆破火炬松（SELP）上的吸附行为可以用朗缪尔等温线来描述。发现纤维素结晶度先增加后减少，随着预处理强度的增加而减少。发现预处理火炬松的初始水解速率与结晶度指数（CrI）之间存在线性关系；此外，还证实了 X 射线衍射强度与初始速率之间存在很强的相关性。这些发现表明 CrI 在预处理木质纤维素生物质的酶水解中具有重要意义。
