Biomimetic and Rubisco-Inspired CO2 Capture from Air

在这个由化学系化学结构、动态和机理B计划资助的项目中，哥伦比亚密苏里大学化学系的Rainer Gaser教授正在开发用于从空气中可逆捕获二氧化碳的二氧化碳捕获和释放(CCR)系统。这种仿生CCR系统的设计是基于对Rubisco酶活性部位二氧化碳结合的理解。为了在田间试验中演示CCR概念，开发了一种在农业温室中进行二氧化碳浓缩的简单装置。未来的用途是大规模、分布式地清除空气中的二氧化碳，并随后永久捕获和储存二氧化碳。该项目提供跨学科培训(机械、结构和计算化学；蛋白质合成和生物材料)。通过开发科学传播中的“化学在新闻中”项目和科学写作课程来指导学生关于科学过程、科学写作、科学同行评议和职业道德，还产生了其他更广泛的影响。利用小分子模型对二氧化碳捕获反应进行了详细的热力学分析，证明了受Rubisco启发的小肽仿生技术有望成为二氧化碳释放能量需求较低的CCR系统。要实现高能效的CCR系统，需要开发具有相当大的负反应熵的二氧化碳捕获反应。本研究的目标是用捕获热化学方法确定最适合有效捕获和能量高效释放的小肽。为此，合成了游离型和固定化四肽文库。具体的实验包括(A)二氧化硅颗粒的合成和表面功能化，(B)多肽在各种载体上的固定化，(C)光谱和多肽结晶学的表征，(D)二氧化碳吸附/解吸的定量测量，以及(E)二氧化碳浓缩的简单装置的制造。实验工作还伴随着对四肽库的理论研究，以确定镁络合四肽中二氧化碳加成的热化学和动力学，以评估镁的替代品。

In this project, funded by the Chemical Structure, Dynamic & Mechanism B Program of the Chemistry Division, Professor Rainer Glaser of the Department of Chemistry at the University of Missouri, Columbia is developing carbon dioxide capture and release (CCR) systems for the reversible carbon dioxide capture from air. The design of this biomimetic CCR systems is informed by the understanding of the binding of carbon dioxide in the active site of the enzyme rubisco. A simple device for carbon dioxide enrichment in agricultural greenhouses is developed to demonstrate the CCR concept in a field test. Future use is envisioned for large-scale, distributed carbon dioxide removal from air and its subsequent permanent capture and storage. The project provides cross-disciplinary training (mechanistic, structural and computational chemistry; protein synthesis, and biomaterials). Additional broader impacts are achieved through the development of the "Chemistry is in the News" project in science communication and the scientific writing curriculum to instruct students about the scientific process, scientific writing, scientific peer review, and professional ethics. Detailed thermodynamic analyses performed for the carbon dioxide capture reaction with a small molecule model demonstrates the promise of rubisco-inspired, small peptide biomimetics as CCR systems with low energy requirements for carbon dioxide release. The realization of energy-efficient CCR systems requires the development of carbon dioxide capture reactions with negative reaction entropies of substantial magnitude. It is the goal of this research to identify small peptides with capture thermochemistry most suitable for effective capture and energy-efficient release. For this purpose, libraries of free and immobilized tetrapeptides are synthesized. Specific experiments include (a) silica particle synthesis and surface functionalization,(b) peptide immobilization on various supports,(c) characterization by spectroscopy and by peptide crystallography,(d) quantitative measurements of carbon dioxide sorption/desorption,and (e) the fabrication of a simple device for carbon dioxide enrichment. The experimental effort is accompanied by theoretical studies of the library of tetrapeptides to determine the thermochemistry and the kinetics of the carbon dioxide addition to the magnesium complexed tetrapeptides, to assess alternatives to magnesium.