Collaborative Research: Enzyme-Mimicking Catalysts for Cellulose Processing

在化学系化学催化计划的支持下，爱荷华州立大学的赵燕和东北大学的董思佳正在研究通过分子印迹来模拟天然纤维素酶的合成催化剂的开发。化石燃料仍然是人类能源和化学原料的主要来源，但对其可持续性和对环境/生态的负面影响的担忧促使许多人寻找替代能源。来自植物的木质纤维生物质是一个可行的替代方案。它是一种可再生的碳中性材料，每年生产170-2000亿吨。不幸的是，纤维素聚合物的化学稳定性和纤维素纤维的高度结晶性阻碍了纤维素的解聚，这是生物质转化的关键步骤。尽管天然纤维素酶是纤维素解聚的有力催化剂，但它们的生产成本往往很高，而且难以回收利用。相比之下，赵和董的研究小组正在开发的合成催化剂是坚固的聚合物纳米颗粒，可以耐高温、有机溶剂和其他不利反应条件。他们预计将极大地扩大解聚过程的操作窗口，使其更具工业可行性。这项研究的多学科性质将通过让学生接触催化、聚合物化学、计算化学、酶学和物理有机化学来为他们提供有价值的培训。赵和董团队的教育和外展活动包括校内外项目，旨在吸引本科生参与研究，并增加K-12学生对STEM(科学、技术、工程和数学)的接触。纤维素的解聚是生物质转化的关键步骤，但糖苷键的稳定性和纤维素纤维的高结晶度阻碍了这一步骤。这项研究是通过分子印迹纳米粒子的发展，对分别模拟内纤维素酶、胞外纤维素酶和β-葡萄糖苷酶的纳米粒子催化剂进行的实验和理论研究。爱荷华州立大学的实验工作重点是优化受天然酶启发的合成催化剂的结合和催化结构域。东北大学的理论工作集中在对活性中心的计算模拟，以更好地了解催化，并被用于指导和设计活性中心。如果成功，这项研究将生产出比天然纤维素酶活性更好的合成催化剂，但更容易制备和回收。这一奖项反映了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。

With the support of the Chemical Catalysis Program in the Division of Chemistry, Yan Zhao of Iowa State University and Sijia Dong of Northeastern University are studying the development of synthetic catalysts by molecular imprinting to mimic natural cellulases. Fossil fuels continue to be the dominant source of energy and chemical feedstocks to humanity but concerns about their sustainability and negative environmental/ecological impact have prompted many to look for alternatives. Lignocellulosic biomass from plants is a viable alternative. It is a renewable, carbon-neutral material produced at a scale of 170–200 billion tons per year. Unfortunately, the depolymerization of cellulose that is a key step in biomass conversion is hampered by the chemical stability of cellulose polymers and the highly crystalline nature of cellulose fibers. Although natural cellulases are powerful catalysts for cellulose depolymerization, they are often expensive to produce and difficult to recycle. In contrast, the synthetic catalysts that the Zhao and Dong research groups are developing are robust polymeric nanoparticles that can tolerate high temperatures, organic solvents, and other adverse reaction conditions. They are expected to greatly expand the operation window of the depolymerization process, making it more industrially viable. The multidisciplinary nature of this research will provide valuable training to students by exposing them to catalysis, polymer chemistry, computational chemistry, enzymology, and physical organic chemistry. The education and outreach activities of the Zhao and Dong teams involve both on- and off-campus programs that aim to engage undergraduates in research and increase the exposure of K–12 students to STEM (science, technology, engineering and mathematics).The depolymerization of cellulose is a key step in biomass conversion that is hampered by the stability of the glycosidic bonds and high crystallinity of cellulose fibers. The proposed research is a combined experimental and theoretical investigation on nanoparticle catalysts to mimic endocellulase, exocellulase, and β-glucosidase, respectively, through the development of molecularly imprinted nanoparticles. The experimental work at Iowa State University focuses on the optimization of the binding and catalytic domains of the synthetic catalysts inspired by the natural enzymes. The theoretical work at Northeastern University centers on computational simulation of the active sites for a better understanding of catalysis and is being used to guide and design active sites. If successful, the research will yield synthetic catalysts for cellulose hydrolysis than can compete with natural cellulases in activity but that are much easier to prepare and recycle.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.