Collaborative Research: Elucidating the roles of biogenic exudates in the cycling and uptake of rare earth elements

细菌催化了许多过程，这些过程对从局部到全球范围的元素流动至关重要。在许多情况下，这些过程是由酶推动的，酶需要特定的金属离子才能起作用。在过去的十年中，镧和其他稀土元素（REYs），长期以来被认为在生物学中缺乏作用，已被确定为多种细菌使用的酶的辅助因子。这一令人兴奋的发现进一步扩展了生命周期表，并提出了许多关于REYs生物地球化学的问题。该项目的一个核心问题是，由于REYs在大多数环境中并不丰富，细菌需要特定的策略从它们的环境中获取这些元素。该项目将识别和表征与细菌摄取REYs相关的分子。由于REYs是难以从矿石和废物中纯化的战略材料，因此研究结果不仅对理解生物过程很重要，而且可能对经济竞争力和国家安全产生影响。越来越多的人认识到微生物对必需微量金属的吸收是由生物螯合剂介导的。最近发现甲基营养和其他多种细菌的PQQ型I醇氧化酶需要REYs，再加上REYs以非生物可利用的化学形式自然存在，导致了结构独特但尚未确定的生物螯合剂（镧载体）促进土壤中REYs的溶解和吸收的假设。该项目将微生物学与协调、土壤和分析化学方法相结合，以鉴定和表征镧载体、促进土壤和其他基质中REYs的增溶和结合的细菌配体。该项目的结果有可能改变我们对REYs在生物系统中的重要性及其对营养循环的影响的看法，并修订目前对营养吸收和微生物与矿物基质之间关系的看法。该奖项反映了美国国家科学基金会的法定使命，并通过使用基金会的知识价值和更广泛的影响审查标准进行评估，被认为值得支持。

Bacteria catalyze numerous processes that are critical for the flow of elements at local to global scales. In many cases, these processes are fueled by enzymes that require specific metal ions to function. In the last decade, lanthanum and other rare earth elements (REYs), which have long been thought to lack a role in biology, have been identified as cofactors for enzymes used by diverse bacteria. This exciting discovery further expands the periodic table of life and raises many questions about the biogeochemistry of REYs. A central tenant of the project is that, because REYs are not abundant in most environments, bacteria require specific strategies to acquire these elements from their environments. This project will identify and characterize molecules associated with bacterial uptake of REYs. Because REYs are strategic materials that are difficult to purify from ores and waste products, the results are not only important for understanding biological process but also may have implications for economic competitiveness and national security. There is a growing recognition that the microbial uptake of essential trace metals is mediated by biogenic chelating agents. The recent discovery that REYs are required for PQQ Type I alcohol-oxidizing enzymes in methylotrophic and other diverse bacteria coupled with the natural presence of REYs in non-biologically available chemical forms lead to the hypothesis that structurally distinct, but as-yet unidentified, biogenic chelating agents (lanthanophores) facilitate the solubilization and uptake of REYs from soils. This project combines microbiology with coordination, soil, and analytical chemical approaches to identify and characterize lanthanophores, bacteriogenic ligands that promote solubilization and binding of REYs from soils and other matrices. The result of this project have the potential to transform our view of the importance of REYs in biological systems and their impact on nutrient cycling and revise current thinking towards nutrient uptake and the relationships between microorganisms and mineral matrices.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.