Collaborative Research: The chemistry of lignin's photochemical transformation in the environment: implications for global carbon cycling

合作研究：环境中木质素光化学转化的化学：对全球碳循环的影响

• 批准号: 1610021
• 负责人: Patrick Hatcher
• 金额: $ 33万
• 依托单位: Old Dominion University Research Foundation
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 2016
• 资助国家: 美国
• 起止时间: 2016-08-01 至 2020-07-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1610021&HistoricalAwards=false
• 关键词: Collaborative; Research; chemistry; lignin; photochemical

In this project funded by the Environmental Chemical Sciences program of the Chemistry Division, Drs. Patrick Hatcher of Old Dominion University, Satish Myneni of Princeton University, and Christopher Hadad of The Ohio State University employ a multidisciplinary approach to study lignin, a complex organic polymer deposited in the cell walls of many plants, making them rigid and woody. Lignin is an Earth abundant organic biopolymer that provides the starting point to recycle carbon from plants into the environment. In this project, the researchers explore pathways for the molecular rearrangement of lignin to form the molecules present in soil, water and sediments. A postdoctoral associate, graduate students, and several undergraduates are trained to combine geochemistry, fundamental molecular studies, advanced analytical techniques, and modern computational modeling of complex reaction pathways. This training provides these future scientists with an interdisciplinary experience. Undergraduate and high school engagement, including diversified recruitment, is included.In this research project, lignin is subjected to oxidative degradation by reactive oxygen species (ROS) to partially reorganize and polymerize to form humic substances. These humic substances may effectively sequester lignin-derived carbon in contrast to the theory that lignin is completely oxidized to carbon dioxide and contribute to greenhouse warming. This research subjects both synthesized and natural lignin to oxidative decomposition by ROS in the presence of aqueous iron species, mimicking environmental oxidation. The study employs Fourier transform ion cyclotron resonance mass spectrometry, multidimensional liquids and solids NMR, and synchrotron-based X-ray absorption spectroscopy to discern molecular transformation pathways. The research also provides new information regarding both the pathways and magnitude with which photochemistry and ROS affect the cycling of terrestrial carbon among Earth's large reservoirs of carbon, impacting the chemistry of terrestrial systems and oceans.

在这个由化学部环境化学科学项目资助的项目中，博士。奥道明大学的 Patrick Hatcher、普林斯顿大学的 Satish Myneni 和俄亥俄州立大学的 Christopher Hadad 采用多学科方法来研究木质素，木质素是一种复杂的有机聚合物，沉积在许多植物的细胞壁中，使植物变得坚硬和木质。 木质素是地球上丰富的有机生物聚合物，为将植物中的碳回收到环境中提供了起点。 在这个项目中，研究人员探索了木质素分子重排形成土壤、水和沉积物中分子的途径。 一名博士后助理、研究生和几名本科生接受了将地球化学、基础分子研究、先进分析技术和复杂反应途径的现代计算建模相结合的培训。 这种培训为这些未来的科学家提供了跨学科的经验。 包括本科生和高中的参与，包括多样化的招聘。在这个研究项目中，木质素受到活性氧（ROS）的氧化降解，部分重组和聚合形成腐殖质。这些腐殖质可以有效地隔离木质素衍生的碳，这与木质素完全氧化成二氧化碳并导致温室变暖的理论相反。这项研究使合成木质素和天然木质素在水性铁物质存在的情况下通过活性氧进行氧化分解，模拟环境氧化。该研究采用傅里叶变换离子回旋共振质谱、多维液体和固体核磁共振以及基于同步加速器的 X 射线吸收光谱来辨别分子转化途径。 该研究还提供了有关光化学和活性氧影响地球大型碳库中陆地碳循环、影响陆地系统和海洋化学的途径和程度的新信息。