Engineered Cyanobacteria for High Current Density Photosynthetic Fuel Cells
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Solution Overview
Problem
Current photo-bioelectrochemical cells and microbial fuel cells based on photosynthetic microorganisms like cyanobacteria have lower current densities compared to standard solar cells and biofuel cells, limiting their competitiveness.
Innovation Solution
Engineered photosynthetic cells and organisms are developed by introducing an exogenous nucleic acid encoding a non-native redox enzyme, such as outer membrane cytochrome from Geobacter, to enhance extracellular electron transport, combined with nanostructured materials for improved electron transfer in photo-bioelectrochemical cells and microbial fuel cells.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If cyanobacteria are used in photo-bioelectrochemical cells, then the system is clean and renewable, but the current density is two orders of magnitude lower than exoelectrogens in MFC
Solution Approach 1:
The patent combines cyanobacteria (photosynthetic organisms) with exoelectrogenic capabilities by introducing heterologous electron transport proteins. This merging integrates the environmental benefits of photosynthesis with the high current density of exoelectrogens, creating a hybrid system that maintains cleanliness while achieving competitive productivity.
Solution Approach 2:
The engineered cyanobacteria represent a composite biological system, combining native photosynthetic machinery with foreign electron transport proteins (MtrA, OmcA, CymA). This composite approach allows the organism to simultaneously perform photosynthesis and extracellular electron transfer, resolving the contradiction between environmental cleanliness and high current density.
2Device complexity
If isolated photosynthetic organelles are used, then the system is simplified, but the stability is lower than whole cells
Solution Approach 1:
The patent extracts only the essential electron transport proteins (MtrA, OmcA, CymA) from exoelectrogenic bacteria and introduces them into cyanobacteria. This selective extraction avoids the complexity of using entire exoelectrogenic organisms while maintaining their high current density capability, and the cyanobacteria whole cell structure provides the necessary stability.
3Productivity
If standard solar cells are used, then the current density is high, but the system is not renewable and requires external organic carbon sources
Solution Approach 1:
The engineered cyanobacteria are self-sufficient, using only light and water as inputs through photosynthesis to generate electrons for electricity production. They do not require external organic carbon sources, making the system renewable and environmentally clean while achieving improved current density through the introduced electron transport proteins.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The engineered cells exhibit significantly higher extracellular electron transfer rates and photocurrent generation, increasing current densities and efficiency, making them more competitive with existing energy conversion technologies.
Implementation Method 1
extracellular electron transport
Implementation Method 2
photosynthesis, a process that evolved over 2.5 billion years
Implementation Method 3
combined with nanostructured materials for improved electron transfer
Data Source
AI summary
The present disclosure provides engineered photosynthetic cells and organisms, methods for engineering photosynthetic cells and organisms with increased extracellular electron transport, photo-bioelectrochemical cells (PBECs), anodes for a PBECs and/or photosynthetic microbial fuel cells (PMFCs), methods of generating an electrical current with PBECs, and methods and systems for generating H2 fuel.