Nanoscale Imaging of Microbial-Mineral Interactions (NIMMI)

微生物过程介导了许多金属和放射性核素的氧化还原状态，这反过来又控制了它们在环境中的流动性和各种矿物相的稳定性。有机物也受到这些过程的影响，它们要么作为金属/矿物还原的电子供体，要么作为竞争的电子受体，例如在氯化溶剂的情况下。分子生态学、基因组学和后基因组学技术的进步，通常在遗传水平上，使我们对负责这些重要过程的生物体的多样性和基础生理学有了深刻的了解。与此同时，纳米级成像和光谱学的发展现在提供了揭示这些生物过程如何在原子尺度上影响地圈的潜力。该项目的目的是通过结合最先进的同步加速器成像技术，包括STXM，以及微生物学，显微镜学，地球化学和建模方法，在纳米尺度上对关键的微生物-矿物相互作用有更深入的了解。三个互补和相互联系的主要环境重要性系统是本调查的重点。首先，我们将解决不溶性铁（III）氢氧化物的微生物还原，它在地下环境中的许多耦合生物地球化学过程中起着重要作用，以确定控制这种普遍存在的厌氧呼吸形式的纳米级过程。接下来，我们将重点关注吸附在铁（III）氢氧化物上的As(V)的还原动员，以确定这一生物过程的机制，该过程被认为是由铁（III）还原细菌催化的，并威胁着全球数千万人的生命。最后，还将研究Fe（III）还原系统中U（VI）的生物还原，这可能会限制铀的溶解度，因为它与我们现有的土壤污染和遗留核废料的管理有相当大的相关性，但在机制层面上知之甚少。通过这一方案，申请人的目的是获得明确的证据，以帮助我们了解这些重要过程的确切机制，这些过程已经被世界各地的许多团体研究了十多年，但仍然难以捉摸。影响将遍及广泛的科学界，在非常引人注目的领域，包括污染物生物修复、微量金属/类金属生物地球化学和我们遗留核废料的长期安全管理，建立更强大的概念和数值模型。利益相关者的参与将通过曼彻斯特与英国和世界各地涉及土地和水质以及核废料处理的关键中心之间已经存在的紧密联系来实现。我们还将把北美和欧洲同步加速器设施的软x射线和STXM专业知识转移到英国钻石同步加速器（正在建设中的光束线），同时培训英国的关键人员，以最大限度地利用这些令人兴奋和强大的新世界级设施。

Microbial processes mediate the redox state of many metals and radionuclides, which in turn controls their mobility in the environment and the stability of a wide range of mineral phases. Organics are also influenced by these processes, acting either as electron donors for metal/mineral reduction, or as competing electron acceptors, for example in the case of chlorinated solvents. Advances in molecular ecology, genomics and post-genomic technologies have given us significant insight into the diversity of the organisms responsible for these important processes, and the underpinning physiology, often at a genetic level. In parallel, developments in nano-scale imaging and spectroscopy now offer the potential to reveal how these biological processes impact on the geosphere at an atomic-scale. The aim of this project is to gain a deeper understanding of key microbial-mineral interactions at the nano-scale using a combination of new state of the art synchrotron imaging techniques, including STXM, alongside microbiological, microscopy, geochemical and modelling approaches. Three complementary and interlinked systems of major environmental importance are the foci of this investigation. First, we will address the microbial reduction of insoluble Fe(III) oxyhydroxides, which plays a major role in many coupled biogeochemical processes in subsurface environments, to identify the nano-scale processes controlling this ubiquitous form of anaerobic respiration. Next, we will focus on the reductive mobilisation of As(V) sorbed onto Fe(III) oxyhydroxides, to identify the mechanism of this bioprocess thought to be catalysed by Fe(III)-reducing bacteria, and threatening the lives of tens of millions worldwide. Finally, the bioreduction of U(VI) in Fe(III)-reducing systems, which potentially limits uranium solubility, will also be studied as it has considerable relevance to the management of our existing soil contamination and our legacy nuclear waste, but is poorly understood at a mechanistic level.Through this programme, the applicants aim to obtain definitive evidence to help us understand the precise mechanisms of these important processes, which have been studied for more than a decade by many groups world-wide, but remain elusive. Impact will be across a broad scientific community, underpinning more robust conceptual and numerical models in very high profile areas including contaminant bioremediation, trace metal/metalloid biogeochemistry and the safe long-term stewardship of our legacy nuclear waste. Stakeholder engagement will be through strong links that already exist between Manchester and key centres involved in land and water quality and nuclear waste disposal, in the UK and worldwide. We will also enable the transfer of soft x-ray and STXM expertise from synchrotron facilities in North America and Europe to the UK Diamond synchrotron (beamline under construction), while training of key personal in the UK to make maximal use of these exciting and powerful new world-class facilities.