Collaborative Research: Identification of Lignin-derived Ligands Associating With Iron

在美国国家科学基金会化学部环境化学科学项目的支持下，内华达大学的于洋、俄勒冈州立大学的雷诺和雷内·博伊特奥正在研究来自木质素有机化合物的铁配合物。与氧化铁有关的有机碳是地球表面最大的碳库之一。预测土壤碳库大小的变化并可持续地管理土壤和水质是一项重要的挑战。对铁-有机碳络合物的化学性质的严格理解有可能帮助科学家们进行这一努力。到目前为止，土壤有机碳与铁的络合物的来源和形成机制尚不清楚。作为土壤有机碳的主要前体，植物来源的木质素可以被降解成可能与铁氧化物结合的化合物。该项目旨在揭示木质素衍生的铁配体的化学性质。土壤碳是地球碳循环的重要组成部分，也是这一循环中与气候高度相关的元素。研究生、本科生和K-12年级的学生将在这两所大学从事这项研究。利用国家科学基金会资助的研究生教育创新项目，将开发一个夏令营模块，重点关注与可持续发展相关的环境化学，以增加第一代学生和代表性不足的群体在科学研究生学习中的代表性。本项目致力于开发目标和非目标的方法，结合高分辨率电喷雾电离质谱仪和电感耦合等离子体质谱检测和定量木质素衍生的配体及其铁络合物。该方法将用一组已知的木质素降解产物进行开发和验证，并用于表征纯培养和土壤培养中木质素微生物降解形成的铁结合产物。预计这些研究将有助于阐明生物聚合物(木质素)衍生的铁配体及其络合物的化学性质，并为深入了解土壤有机碳的分级，最终控制土壤有机碳储量的化学机制提供帮助。这样的理解对于开发土壤受限有机碳的性质和形式的预测模型至关重要。该项目开发的方法预计将广泛适用于土壤和水环境中其他生物聚合物(纤维素、角质和其他)衍生配体的研究。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。

With support from the Environmental Chemical Sciences Program of the NSF Division of Chemistry, Yu Yang of the University of Nevada, Reno and Rene Boiteau of Oregon State University are studying iron complexes derived from lignin-based organic compounds. Iron oxide-associated organic carbon is one of the largest reservoirs of carbon on the Earth’s surface. Predicting changes to the size of soil carbon reservoirs and sustainably managing soil and water quality is an important challenge. A rigorous understanding of the chemical nature of iron-organic carbon complexes has the potential to assist scientists in this endeavor. So far, the origin and formation mechanism of soil organic carbon in complex with iron remain poorly understood. As a primary precursor for soil organic carbon, plant-derived lignin can be degraded into compounds that may bind to iron oxides. This project aims to uncover the chemical nature of lignin-derived ligands for iron. Soil carbon is an important part of the Earth's carbon cycle, and an element of this cycle that is highly relevant to climate. Graduate, undergraduate, and K-12 students will be engaged in this research at both institutions. Leveraging an NSF-funded Innovations in Graduate Education project, a summer camp module will be developed focusing on environmental chemistry relevant to sustainability, to increase the representation of first-generation students and underrepresented groups in graduate studies in science. This project sets out to develop targeted and non-targeted methods to detect and quantify lignin-derived ligands and their iron complexes by liquid chromatography together with high resolution electrospray ionization mass spectrometry and inductively coupled plasma mass spectrometry. The method will be developed and validated with a set of known lignin degradation products and used to characterize the iron-binding products formed by microbial degradation of lignin in pure culture and soil incubation. It is expected that these studies will help elucidate the chemical nature of biopolymer (lignin)-derived iron ligands and their complexes and provide insights into the chemical mechanisms that fractionate soil organic carbon, ultimately governing soil organic carbon stocks. Such understanding is critical for developing predictive models for the nature and form of soil-constrained organic carbon. The methods developed in this project are expected to be broadly applicable for the investigation of other biopolymer (cellulose, cutin, and others)-derived ligands in soil and aqueous environments.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.