Charge transfer at abiotic-biotic interface for photosynthetic biohybrids

该奖项是与ENG/CBET电化学系统计划共同资助的，用于光合作用生物杂交种的非生物-生物界面的充电转移快速发展的工业世界需要创造性和可持续的战略来应对单向碳循环。将二氧化碳转化为以太阳能为动力的增值产品是理想的解决方案。将单细胞微生物与捕光纳米材料相结合，形成光合作用生物杂交系统(PBS)是一种很有前途的方法。生物微生物利用一系列酶和还原途径，从包括二氧化碳、氮气和水在内的简单构件中产生长链碳氢化合物。半导体纳米材料具有可调的宽带光吸收和表面电荷的高度可配置性，与微生物配对良好，能够显著捕获阳光，从而将太阳能转化为化学物质。这些光合作用生物杂化材料增强了生物全细胞催化剂和半导体纳米材料的最佳功能。然而，由于生物/非生物半导体/细菌界面的复杂性，这些新兴的光合作用生物杂化材料中的基本电子传递和能量传递途径在很大程度上仍未被探索。本项目的目的是研究这种能量传递途径，从半导体纳米结构对太阳光的吸收开始，电子的产生和从半导体到微生物的转移，然后微生物利用转移的电子还原二氧化碳。通过利用可再生能源(即太阳能和人工光合作用)将化石燃料燃烧的主要副产品二氧化碳减少到增值燃料中，可以帮助关闭碳排放循环，减少二氧化碳排放，并使我们的社会更可持续。从光合作用生物杂交系统产生的简单分子开始，可以构建更复杂的物质，如化肥、工业和商品化学品、聚合物和药品等，所有这些都源于捕获大气中的二氧化碳。与研究工作相结合，PI还提出了一个教育项目，旨在刺激和准备大学预科学生在材料科学和能源研究方面的职业生涯，包括在当地中学的外展努力(湾区科学家在学校，以及夏季STEM实习)。TECHNICAL SUMMARYLING太阳光代表了一种新形式的化学能，从太阳能转化并储存在化学键中。光合作用生物杂交体通过可通过时空成像和光谱分析探测到的“光子输入、化学键合”材料/生物界面产生液态阳光。光合作用生物杂化系统(PBS)结合了生物全细胞催化剂和半导体纳米材料的最佳特性。包裹在其天然细胞环境中的酶机械提供了精致的产品选择性和较低的底物激活势垒，而半导体纳米材料比生物分子更稳定和更有效地获取光能。最近，已经证明，利用这些光合作用生物杂化材料，可以直接从二氧化碳中生产一系列增值化学品，如液体燃料、可生物降解聚合物和其他复杂的天然产品。然而，由于生物/非生物半导体/细菌界面的复杂性，这些新兴的光合作用生物杂化系统中的基本电子传递和能量传递途径仍未被探索。从根本上说，这些PBSS的光合作用功能来自于一个在长度和时间尺度上跨越多个数量级的“光子输入、化学键合”材料/生物界面。本研究的目的是通过对无机光敏剂的界面电荷转移和生物矿化的研究，设计和探索无机-生物人工光合作用模型体系的基本非生物-生物界面。这项模型系统研究将需要三个阶段：1)阐明伍德-永达路径中光敏剂和生物参与者之间的电荷转移；2)光敏剂生物矿化和光敏剂-全细胞电荷转移的详细研究；3)开发一个功能性的全细胞光敏系统，并筛选矿物前体和空穴清除剂对系统生产力的影响。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。

This award is Co-Funded with ENG/CBET Electrochemical Systems programCharge transfer at the abiotic-biotic interface for photosynthetic biohybridsNON-TECHNICAL SUMMARYA rapidly developing industrial world requires creative and sustainable strategies for dealing with the unidirectional carbon cycle. The conversion of CO2 to value-added products powered with solar energy is an ideal solution. Combining single-cell microorganisms with light-harvesting nanomaterials into photosynthetic biohybrid systems (PBS) represents a promising approach. Biological microorganisms engage a collection of enzymes and reductive pathways to produce long-chain hydrocarbons from simple building blocks, including CO2, N2, and H2O. Semiconducting nanomaterials are highly configurable with tunable broadband light absorption and surface charge, pair well with microorganisms and enable significant sunlight capture, hence solar-to-chemical conversion. These photosynthetic biohybrids boost the best functions of biological whole-cell catalysts and semiconducting nanomaterials. However, the fundamental electron transfer and energy transduction pathway in these emerging photosynthetic biohybrids remains largely unexplored due to the complex nature of the biotic/abiotic semiconductor/bacteria interfaces. The purpose of this project is to examine this energy transduction pathway, starting from solar light absorption by the semiconductor nanostructures, electron generation and transfer from the semiconductor to microorganism, and then CO2 reduction by the microorganism using transferred electron. By reducing CO2, the major byproduct of fossil fuel combustion, into value-added fuels using renewable energy sources (i.e., solar energy and artificial photosynthesis), one can help close the carbon emission loop, mitigate CO2 emissions, and make our society more sustainable. Starting from the simple molecules produced by photosynthetic biohybrid systems, more complex substances, like fertilizers, industrial and commodity chemicals, polymers, and pharmaceuticals, among others, can be constructed, all originating from capturing atmospheric CO2. Integrated with the research effort, the PI also proposes an educational project that stimulates and prepares pre-college students for careers in materials science and energy research, including outreach efforts at local middle-high schools (Bay Area Scientists in Schools, and summer STEM internship).TECHNICAL SUMMARYLiquid sunlight represents a new form of chemical energy converted and stored in chemical bonds from solar energy. Photosynthetic biohybrids produce liquid sunlight through a “photon-in, chemical bond-out” materials/biology interface that can be probed through spatiotemporal imaging, and spectroscopic analyses. Photosynthetic biohybrid systems (PBS) combine the best attributes of biological whole-cell catalysts and semiconducting nanomaterials. Enzymatic machinery enveloped in its native cellular environment offers exquisite product selectivity and low substrate activation barriers while semiconducting nanomaterials harvest light energy stably and more efficiently than biomolecules. Recently, it has been demonstrated that a collection of value-added chemicals, such as liquid fuels, biodegradable polymers, and other complex natural products can be directly produced from CO2 using these photosynthetic biohybrids. However, the fundamental electron transfer and energy transduction pathway in these emerging photosynthetic biohybrid systems remains unexplored due to the complex nature of the biotic/abiotic semiconductor/bacteria interfaces. Fundamentally, the photosynthetic function of these PBSs originates from a “photon-in, chemical bond-out” materials/biology interface that spans multiple orders of magnitude both in the length and time scale. The objective of this research is to design and explore the fundamental abiotic-biotic interfaces of a model system for inorganic-biological artificial photosynthesis through studies on interfacial charge transfer and biogenic mineralization of inorganic photosensitizers. This model system study will require three phases: 1) elucidation of charge transfer between photosensitizers and biological participants in the Wood-Ljungdahl Pathway; 2) a detailed study of photosensitizer biomineralization and photosensitizer-whole cell charge transfer; and 3) development of a functional whole-cell photosensitized system and screening the effects of mineral precursor and hole scavenger on system productivity.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.