Collaborative Research: Microbial Fuel Cell Optimization through Digital Microfluidic Electrochemistry in Single-Bacterial Drops

合作研究：通过单细菌液滴中的数字微流体电化学优化微生物燃料电池

• 批准号: 1605482
• 负责人: Daniel Hassett
• 金额: $ 15.2万
• 依托单位: University of Cincinnati Main Campus
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2016
• 资助国家: 美国
• 起止时间: 2016-08-01 至 2019-07-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1605482&HistoricalAwards=false
• 关键词: Collaborative; Research; Microbial; Fuel; Cell

Municipal wastewater treatment processes consume significant amounts of energy. However, the organic materials fed into the waste treatment process offer the potential for energy-positive waste water treatment if this waste organic material can be converted into energy. Many bacteria that grow in waste water can be harnessed to consume these organic contaminants to clean up the water and at the same time generate electrical current from their metabolism. These bacteria are bound within an electrode of a device called a microbial fuel cell to harvest this current as electrical power. To achieve maximum power output from microbial fuel cells, it must be determined how many species of bacteria, when organized into complex colonies known as biofilms, collaborate to convert organic matter into electricity. This project will study this collaborative metabolism within a novel miniaturized culture system capable of high-through analysis to accelerate the screening process. This miniature culture system will be capable of measuring metabolism of a single bacterial species, as well as in small mixed colonies of many bacteria, from a single drop of culture. This information will be used to determine how the electrical current produced and the organic matter consumed depends on bacterium type, as well as the potential synergy between many types of bacteria. The educational activities inspired by this project feature a hands-on teaching module for high school girls, who will build a simple microbial fuel cell to power a light-emitted diode (LED) or a digital watch. It is hoped this activity will illustrate to high school girls the potential of renewable green energy and biotechnology as exciting future career choices.The microbial fuel cell system components, which include electrodes, membranes, and bacteria, must be carefully engineered to achieve optimal power generation. This project will focus on genetic optimization of the bacteria within the electrode. This optimization is challenging given the interconnected manner in which wastewater bacteria grow. Towards this end, the proposed research has two primary objectives. The first objective is to develop a high-throughput digital microfluidic (DMF) platform for studying microbial fuel cell metabolism and electrical current evolution from single species of bacteria or small colonies of mixed bacteria. The second goal is to optimize the bacterial communities for high power density through high-throughput analysis of single bacterium electron transfer limitations. The DMF chip will be fabricated with droplet actuation electrodes, nanostructured electrochemical electrodes, and isolated on-chip microwell cell culture chambers. The droplet actuation electrode deposits a culture droplet into the microwell, and nanostructured electrodes within the culture microwell will enable the detection of single bacterium output current as well as measurement of specific cell culture contents using cyclic voltammetry. Bacteria known to consume organic matter in waste water and convert it into electrical current through microbioelectrochemical metabolic processes, including P. aeruginosa, Geobacter (G. sulfurreducens) and Shewanella (S. oneidensis) will first be studied as the model exoelectrogens in single species culture. By selectively increasing complexity and heterogeneity in the culture systems, beginning with isolated single species and moving to mixed bacterial colonies, a better understanding of the synergism among bacteria can be systematically determined. Through this study, it also is hoped that the DMF chip will become established as a new tool for studying electron transfer processes in bioelectrochemically-active bacteria.

城市污水处理过程消耗大量能源。 然而，如果这种废弃的有机材料可以转化为能量，则进料到废物处理过程中的有机材料提供了能量正的废水处理的潜力。 许多在废水中生长的细菌可以被利用来消耗这些有机污染物来净化水，同时从它们的新陈代谢中产生电流。 这些细菌被束缚在一种叫做微生物燃料电池的装置的电极内，以收集这种电流作为电力。 为了实现微生物燃料电池的最大功率输出，必须确定有多少种细菌，当组织成称为生物膜的复杂菌落时，合作将有机物质转化为电能。 该项目将在一种新型的小型化培养系统中研究这种协同代谢，该系统能够进行高通量分析，以加速筛选过程。 这种微型培养系统将能够从一滴培养物中测量单个细菌物种以及许多细菌的小混合菌落的代谢。 这些信息将用于确定产生的电流和消耗的有机物如何取决于细菌类型，以及许多类型细菌之间的潜在协同作用。 受该项目启发的教育活动为高中女生提供了一个实践教学模块，她们将构建一个简单的微生物燃料电池，为发光二极管（LED）或数字手表供电。 希望这次活动能向高中女生说明可再生绿色能源和生物技术作为令人兴奋的未来职业选择的潜力。微生物燃料电池系统的组成部分，包括电极，膜和细菌，必须经过精心设计，以实现最佳的发电。该项目将重点关注电极内细菌的遗传优化。 考虑到废水细菌生长的相互关联方式，这种优化具有挑战性。为此，拟议的研究有两个主要目标。第一个目标是开发一个高通量的数字微流体（DMF）平台，用于研究微生物燃料电池的代谢和电流演变从单一物种的细菌或混合细菌的小菌落。第二个目标是通过对单个细菌电子传递限制的高通量分析来优化高功率密度的细菌群落。DMF芯片将制造有液滴驱动电极、纳米结构电化学电极和隔离的芯片上微孔细胞培养室。 液滴致动电极将培养液滴沉积到微孔中，并且培养微孔内的纳米结构化电极将使得能够使用循环伏安法检测单个细菌输出电流以及测量特定的细胞培养物内容物。 已知消耗废水中的有机物质并通过微生物电化学代谢过程将其转化为电流的细菌，包括铜绿假单胞菌、吉西他滨（G. sulfurreducens）和希瓦氏菌（S. oneidensis）将首先作为单一物种培养中的模式外生产电菌进行研究。 通过选择性地增加培养系统的复杂性和异质性，从分离的单一物种开始，并移动到混合细菌菌落，可以系统地确定细菌之间的协同作用的更好的理解。 通过这项研究，也希望DMF芯片将成为一个新的工具，研究生物电化学活性细菌的电子转移过程。