Global human energy consumption is expected to increase by over 30% in the next 15 years. Although there is more than enough energy in sunlight to meet this challenge, efficient means to concentrate this diffuse solar energy and store it have not yet been developed. Photosynthesis is the biological process by which green plants and some microorganisms capture and store solar energy; they use it to convert carbon dioxide to metabolic fuels. However, photosynthesis is inherently an inefficient process; it is limited not by the availability of light from the sun but by the rate of the first step in the chemical reactions by which carbon dioxide is converted into products that are rich in energy. There is therefore unused capacity for the capture and use of solar energy by natural photosynthesis. This program engages teams of researchers from the US and the United Kingdom with the goal to re-invent photosynthesis with enhanced efficiency thereby improving the capacity of photosynthetic organisms to make renewable fuels and enhance food security. In the course of the scientific research, this project will provide research training opportunities for more than 14 people (including both women and underrepresented minorities) at the post-doctoral, graduate and undergraduate levels. The international and interdisciplinary nature of the project will build bridges between the US and UK scientific communities in a range of important scientific areas including synthetic biology, photosynthetic physiology, catalysis, and metabolic regulation. The researchers will engage and inform both the public and other investigators through activities that include peer-reviewed publications, public science lectures, blogs, websites, and popular science articles.
To dramatically enhance the efficiency of photosynthesis, this project will develop a range of mechanisms to electrically connect light-activated electron flow from the photosynthetic reaction center (PSI) to downstream fuel-production pathways. This will include increasing flux through natural pathways, creating electrical connections between distinct microbial cell types by construction of artificial biological nanowires, and employing a soluble, chemical, redox shuttle to transfer reducing equivalents from a light harvesting cell to different fuel-producing cells. These scientific goals will be accomplished through four parallel specific aims. 1. Characterization of the components of (and mechanism for controlling flux through) the natural extracellular electron transfer pathway of the cyanobacterium Synechocystis. 2. Construction of artificial systems to abstract reducing equivalents from PSI; these will compete with natural electron acceptors only under highly reducing conditions. 3. Development of artificial means to move reducing equivalents out of the cytoplasm of Synechocystis. 4. Construction within microbes of artificial fuel-production modules that require only reducing equivalents and carbon dioxide as inputs. The project is highly interdisciplinary and will employ a range of techniques including those from microbiology, molecular biology, synthetic biology, biochemistry, electrochemistry, and protein and metabolic engineering.
This award is supported jointly by the Cellular Dynamics and Function Cluster in the Division of Molecular and Cellular Biosciences and by the Biotechnology, Biochemical and Biomass Engineering Program in the Division of Chemical, Bioengineering, Environmental and Transport Systems.
