Lignocellulosic Biomass Fractionation and Depolymerization with Sub/Supercritical Fluids

开发新的环境友好型技术对于从大量木质纤维素生物质（以下简称生物质）中生产增值产品至关重要。亚/超临界条件下的流体是农业副产品（滞销作物秸秆）和食品工业副产品（马铃薯皮）生物质加工的通用溶剂。加压液体（PL，如亚临界水）和超临界流体（SCF，如超临界水和超临界二氧化碳（SC-CO2））为利用分馏技术获得新的增值产品提供了绿色处理平台。近年来，以PL/SCF作为解聚介质引起了广泛的关注。有报道表明，通过优化反应温度和压力，可以控制水解以获得特定应用的目标增值化合物。但是，所涉及的反应机理、活化能和体积等还有待进一步研究。**申请人迄今为止的研究项目主要集中在使用亚临界水和SC-CO2来确定选定的糖和酚类物质的溶解度，提取生物活性物质，如酚类物质、碳水化合物、青蒿素等，以及在SC-CO2介质中和在热处理辅助下的高压下的反应，以及在新溶剂混合物中化合物的相平衡建模。因此，未来的工作将继续建立在这种专业知识的基础上，进一步为PL/SCF介质的新型组合处理开发做出贡献。**本提案的主要目标是扩展关于增值化合物在PL中的溶解度行为的基础知识，并确定热力学变量和输运性质如何影响PL/SCF介质中的分馏、反应、颗粒形成以及这些过程的组合，以开发进一步的新绿色技术，以获得可在食品和非食品工业应用中具有多种用途的生物质增值产品。在拟议的研究计划中，热力学性质，如溶解度将通过实验测量。平衡研究将允许为分馏和反应过程选择最佳压力和温度。在反应过程中，将使用马铃薯皮和秸秆，并在PL/SCF处理前后测定其纤维素、半纤维素和木质素的含量。新的工艺组合将进行实验研究。分馏后，进一步解聚将被评估，以获得各种增值化合物。在半纤维素中发现的增值化合物可以先去除，然后通过特定反应或在纤维素中富集残渣，将其转化为增值化合物。然后，通过新的工艺开发，获得纳米纤维素纤维/晶体。**依靠创新加工技术开发增值化合物的总体目标将通过实验室规模的基础研究来实现概念验证。一旦新工艺建立，将研究涉及多种生物质谷物作物的应用。对于间歇和半连续系统，将获得有关工艺参数影响的有价值的信息，未来的目标是将其应用于连续系统。PL/SCF技术的使用最大限度地减少或消除了有机溶剂和催化剂的使用，从而最大限度地减少对环境的影响，满足注重环境和健康的消费者日益增长的需求，并通过探索大量可利用的生物质来促进加拿大的生物经济。

Development of new environmentally friendly technologies is crucial to generate value-added products from vast lignocellulosic biomass, herein after referred to as biomass. Fluids under sub/supercritical conditions are versatile solvents for biomass processing of agricultural by-products (unmarketable crop straw) and food industry by-products (potato peel). Pressurized liquid (PL, e.g. subcritical water) and supercritical fluids (SCF), such as supercritical water and supercritical carbon dioxide (SC-CO2) provide a green processing platform to obtain new value-added products using fractionation techniques. Recently, the use of PL/SCF as reaction media has attracted attention for depolymerization. Reports have shown that by optimizing the reaction temperature and pressure, hydrolysis can be controlled to achieve targeted value-added compounds for specific applications. However, the reaction mechanisms involved need to be further investigated as well as their activation energy and volume. **The applicant's research program to date has focused on the use of subcritical water and SC-CO2 to determine solubility of selected sugars and phenolics, extraction of bioactives, such as phenolics, carbohydrates, artemisinin, etc, as well as reactions in SC-CO2 media and under high pressure assisted by thermal processing, and modeling of phase equilibria of compounds in new solvent mixtures. Future work would therefore continue to build on this expertise by further contributions to novel combined processing development in PL/SCF media. **The main objectives of this proposal are to expand fundamental knowledge on solubility behavior of value-added compounds in PL, and to determine how thermodynamic variables and transport properties influence fractionation, reaction, particle formation and the combination of these processes in PL/SCF media to develop further new green technologies to obtain value-added products of biomass that can have a number of uses in food and non-food industrial applications. In the proposed research program, thermodynamic properties, such as solubility will be measured experimentally. Equilibrium studies will allow the selection of optimum pressure and temperature for fractionation and reaction processes. For the reaction process, potato peel and straw will be used where their contents of cellulose, hemicellulose and lignin will be determined before and after treatments with PL/SCF. Novel combination of processes will be experimentally investigated. After fractionation, further depolymerization will be assessed to obtain a diverse range of value-added compounds. Value-added compounds found in hemicellulose can be first removed and then the residues can be converted to value-added compounds through specific reactions or enriching the residue in cellulose. Then, nano-cellulose fiber/crystal will be obtained by novel process development. **The overall goal of developing value-added compounds relying on innovative processing technologies will be accomplished through fundamental research at laboratory scale for proof-of-concept. Once the novel process is established, applications involving diverse biomasses of cereal crops will be investigated. Valuable information on the effect of process parameters will be obtained for a batch and semi-continuous system with a future goal to implement it on a continuous system. The use of PL/SCF technology minimizes or eliminates the use of organic solvents and catalysts, thus minimizing environmental impact and meeting the growing demands of environment- and health-conscious consumers as well as boosting Canada's bioeconomy with the exploration of vast biomass available.