RII Track-4: Elucidating Enzyme-Ionic Liquid Interactions to Enable Effective Lignin Valorization

将社会对以石油为基础的燃料和化学品的依赖转向生物质衍生产品，这不仅对于减少我们的碳使用，而且对于增加我们的能源安全和经济稳定都是重要的。为此，对被视为工农业经济副产品的材料进行无害环境的再利用或升级是可持续做法的最终目标之一。木质素是自然界中含量最丰富的芳香族聚合物，具有结构强度和抗微生物/酶降解作用。它的数量超过1亿干吨，作为造纸和制浆工业的废流。尽管木质素作为原料生产各种化学品的潜力很大，但它仍然是一种未得到充分利用的底物。在目前的生物炼油厂概念下，木质素通常被燃烧来产生蒸汽和电力。将木质素废液转化为高附加值的化学品和材料对生物炼油业的经济可行性和成功至关重要。拟议工作的成功示范将为将相关废液中的木质素转化为高价值商品和特种化学品提供一条新的生物催化路线，极大地减少生物燃料供应链上的障碍。该项目还将整合阿巴拉契亚地区贫困群体在STEM领域的外联和教育活动。阻碍木质素有效转化的两个关键挑战是改善笨重、难于溶解的木质素聚合物与催化剂的接触以及单元间连接的选择性/受控破坏。阐明木质素分解酶与离子液体(IL)的相互作用，将有助于更合理地合成更好的离子液体，并有能力对更好的酶进行重组，以优化其在IL水溶液中的活性。这一EPSCoR研究奖学金为PI提供了一个独特的机会，让他们访问位于能源部S太平洋西北国家实验室的环境分子科学实验室并与其合作。总体目标是通过访问国家主要的科学用户设施，通过延长对EMSL的访问来探索IL-酶界面，并在努力开发将木质素转化为高价值化学品的创新生物催化途径的基础上再接再厉。这项研究将涉及：1)从机理上了解木质素的溶解、选择性解聚和酶与ILS的相容性；2)通过EMSL先进的EPR/核磁共振、生物成像、分光光度和计算化学功能探索新的IL-木素分解酶对，以探索IL-酶-木质素之间的界面作用。对这种相互作用的更好理解将指导我们未来的研究，以设计新的生物相容性ILS，通过定向进化/修饰表面电荷来设计更好的酶，或者探索新的膜/催化剂界面，以进一步提高产品产量和选择性。该奖项反映了NSF的法定使命，并通过使用基金会的智力优势和更广泛的影响审查标准进行评估，被认为值得支持。

Shifting society's dependence on petroleum-based fuels and chemicals to biomass derived products is important not only to reduce our carbon usage but also to increase the robustness of our energy security and economic stability. To that end, the environmentally benign reuse or upgrading of materials considered byproducts of industrial and agricultural economies is one of the ultimate goals of sustainable practices. Lignin, as the most abundant aromatic polymers in nature, provides structural strength and protection against microbial/enzymatic degradation of plants. It is available in quantity of over 100 million dry tons as a waste stream from paper and pulping industry. Despite its great potential as a feedstock for making a wide range of chemicals, lignin is still an underutilized substrate. Under the current bio-refinery concept, lignin is commonly burned to generate steam and electricity. Converting lignin waste streams to high value-added chemicals and materials is critical for the economic viability and success of a bio-refinery industry. The successful demonstration of the proposed work will provide a novel biocatalysis route for valorizing lignin from relevant waste streams to high value commodity and specialty chemicals, greatly reducing barriers along the biofuels supply chain. This project will also integrate outreach and education activities for underprivileged groups from the Appalachian region in STEM fields.Two key challenges hindering effective lignin conversion are to improve the contact of the bulky poorly soluble lignin polymer to the catalyst and the selective/controlled breakdown of inter-unit linkages. Elucidating the interactions of lignolytic enzyme with ionic liquid (IL) will allow a more rational approach to synthesize better ILs and the ability to reengineer better enzymes to optimize their activities in aqueous IL solution. This EPSCoR Research Fellowship provides a unique opportunity for the PI to visit and collaborate with the Environmental Molecular Sciences Laboratory (EMSL) at the Department of Energy (DOE)'s Pacific Northwest National Laboratory. The overarching goal is to explore IL-enzyme interfaces through extended visits to EMSL by accessing the nation's premier scientific user facilities and build on efforts to develop innovative biocatalysis pathways to convert lignin to high value chemicals. The research will involve: 1) mechanistic understanding of lignin solubility, selective lignin depolymerization and enzyme compatibility with aqueous ILs; 2) exploration of new IL-lignolytic enzyme pairs via advanced EPR/NMR, bioimaging, spectrophotometry and computational chemistry capacities at EMSL to probe interfacial interactions between IL-enzyme-lignin. A better understanding of such interactions will guide our future research to design new biocompatible ILs, engineer better enzymes via directed evolution/modifying surface charges, or explore new membrane/catalyst interfaces, to further improve product yield and selectivity.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.