Engineering Bacteria Transmembrane for Efficient Extracellular Electron Transfer
Abstract
Microbial fuel cells (MFCs) can directly convert over 50% of chemical energy stored in many sources of biodegradable organic matters to electrical energy through the microorganism metabolism. The diverse bacteria species and the wide range of fuels make MFC an attractive technology for renewable bioelectric power generation from biomass and from wastewater treatment. For this reason, MFCs andthe relevant bacteria have attracted increasing attention from both academic and industrial communities. However, the current density and power density obtained from the typical Shewanella MFCs are generally too low to satisfy practical applications. Although considerable efforts have been devoted to improving the MFC anodic electrodes by increasing the bacteria loading capacity, or enhancingthe electrode conductivity, the output power density of the MFCs to date appeared to have hit the plateau and can rarely exceeds 3W/m2. This limitation comes from the limited charge transfer efficiency in the transmembrane and extracellular electron transfer processes which generally involve sluggish electron hopping through redox centers. Therefore, to break through the power limit of the current MFCs, it is essential to design and fabricate novel anodic electrodes that can futations to efficiently deliver the metabolic electrons to the external electrodes.Here we propose to engineer at the bacteria levelto fundamentally improve the charge transfer efficiency. We will perform systematic studies from synthesizing novel bacteria-metal hybrid materials, understand the charge transport mechanism within, and achieve the overarching goal of greatly enhanced MFC output performance to a practically relevant level. The focus of the project is to construct and offer insights on extracellular electron transfer mechanisms with transmembrane metal nanoparticles. Specifically, we will: (1) use reduced graphene oxide/metal (e.g. Ag and Cu) electrodes to functionalize the charge-producing microbes (model system: Shewanella) to build a dense and highly biocompatible ba for current, power and Coulombic efficiency tests to evaluate the output performance; (3) explore the extracellular electron transfer mechanisms in bacteria with transmembrane nanoparticles through single cell studies in micro-electrode device and building effective circuit models to obtain comprehensive understanding for future MFC development. The successful demonstration of our proposed concept will open up exciting opportunities for the design and engineering of a new generation of bioelectronic device system for both energy harvesting and bio-sensing.Potential Naval Relevance: The proposed studies aim to elucidate fundamental charge transport mechanism at the bacterium level through microelectronic studies, and to apply the knowledge in the construction of novel bacteria-metal hybrid MFCs that reach the performance level for practical devices. These proposed studies will provide knowledge needed to breakthrough the limitation in exoelectrogenic bacteria extracellular electron transfer. The outcome of the proposed studies will lead to the development a novel approach for the synthesis of bio-materials hybrids, the fundamental understanding of the extracellular electron transfer across the bacteria-inorganic interfaces and establish the important intellectual underpinnings for engineering highly efficient microbial assemblies. The development of highly efficient bacteria-metal hybrid biomaterials could offer a novel pathway to harvest energy from the ocean bacteria, organic waste and bio-mineralization for extended Naval operation.(Approved for Public Release)
Document Details
- Document Type
- DoD Grant Award
- Publication Date
- Apr 06, 2021
- Source ID
- N000142112285
Entities
People
- Yu Huang
Organizations
- Office of Naval Research
- United States Navy
- University of California, Los Angeles