Role of Lignin in Biochemical Conversion of Lignocellulose Biomass into Fuels and Biochemicals

在木质纤维素材料(如木材和农业废弃物)生化转化为燃料和化学品的典型过程中，必须去除半纤维素或木质素，以便纤维素酶更容易获得纤维素分子。木质素占植物质量的20%-30%，因物种不同而不同。木质素是限制纤维素酶与纤维素酶结合的物理屏障，木质素及其衍生物也与纤维素酶结合，即所谓的非生产性结合。本研究的目的是从根本上了解木质纤维素底物中的木质素对生物质转化的影响。我们将使用EM、XPS、CLSM、AFM来确定木质素在预处理过程中的重新分布，并将使用我们实验室专门设计的AFM系统来研究纤维素酶和木质素之间的相互作用力。木质素的含量，木质素的分布，以及不同类型的木质素在底物和水解体系中的组成将被研究，以确定其对底物抵抗酶水解的贡献。为了开发生物质转化技术，世界各地在研究方面做出了许多努力；然而，经济上可行的技术很少。显然，生物质转化过程中更根本的问题需要得到解答。这项拟议的项目将在微米和纳米尺度上对木质纤维素生物质的结构和化学成分有新的理解，并将这些特征与基质的消化率联系起来。预计从这项研究中获得的新知识将为改进现有的生化转化技术和开发经济上可行的工业应用的新的生化转化技术提供至关重要的信息。这项研究计划涉及化学工程、化学、生物、工业流程以及最先进的表面和纳米分析技术领域的专业知识，因此为加拿大的HQP培训提供了一个独特的机会。

In a typical process of biochemical conversion of lignocellulose materials such as wood and agriculture residues into fuels and chemicals, either hemicellulose or lignin has to be removed so that cellulase can access cellulose molecules more easily. Lignin makes up 20%-30% of plant mass varying with species. Lignin acts as a physical barriers restricting access of cellulases to cellulose; and lignin and lignin derivatives also bind with cellulase, so called non-productive binding. The objective of this study is to obtain fundamental understanding of how lignin in the lignocellulose substrate affects biomass conversion. We will use EM, XPS, CLSM, AFM to determine the redistribution of lignin after a pretreatment process, and will use a specially designed AFM system in our lab to study the interactive forces between cellulases and lignin. Lignin content, lignin distribution, and the composition of different types of lignin in substrates and in hydrolysis systems will be investigated for its contribution to substrate recalcitrance to enzyme hydrolysis. Many efforts have been made in research around the world in order to develop technologies for biomass conversion; however, economically viable technologies are scarce. It is clear that more fundamental questions in biomass conversion process need to be answered. This proposed project will gaining new understanding of lignocellulose biomass structure and chemical components at micro- and nano-scale, and link these characteristics to the substrate digestibility. It is expected that new knowledge obtained from this study will provide crucially important information for improving the existing and developing new biochemical conversion technologies which is economically viable for industrial applicaitons. This research program involves expertise in the areas of chemical engineering, chemistry, biology, industrial processes, and state-of-the-art surface and nanoscale analysis techniques, and thus provides a unique opportunity for training HQP’s for Canada.