Oxygen-producing photosynthetic bacteria, known as cyanobacteria, have many properties that make them excellent candidates for the production of green fuels and chemicals. They require few nutrient inputs, can grow in water that is of poor quality for drinking or farming, and can easily be manipulated through genetic engineering. The cyanobacterium Synechococcus elongatus PCC7942 has already been successfully engineered to produce a number of useful chemicals such as alcohols and oils. However, first generation strategies to genetically engineer cyanobacteria resulted in only modest chemical production rates, and did not consider how these rates would be affected by growing bacteria outdoors in a day/night cycle. More effective engineering of cyanobacteria for industrial purposes requires basic research that addresses how these bacteria integrate information related to conditions in the external environment and timing programs inside their cells to make decisions on when to run various aspects of their metabolism. This project will utilize Synechococcus elongatus PCC7942 as a model to address three questions: (1) When Synechococcus transitions from being in light to darkness, is there a specific signaling pathway that detects this change and alters the organism's gene expression and metabolism? (2) Does the internal circadian clock of Synechococcus influence the decision of whether to use carbon immediately for growth or to store it for later use? and (3) How does the cell integrate external environmental signals and internal circadian clock information to subsequently exert control over metabolism? Better understanding of these signaling networks will both expand basic understanding of how cyanobacteria control their metabolism and facilitate more effective genetic engineering efforts that take into account how the bacteria will respond to modifications and external environmental conditions.
Broader Impacts:
This research will answer basic scientific questions about when and how carbon is utilized and stored in a model cyanobacterial system; such information has been essential in the successful engineering of non-photosynthetic bacteria such as Escherichia coli. In doing so this project will enable the engineering of photosynthetic microorganisms to produce fuel and industrial chemicals, decreasing dependence on petroleum for these products. Success in the biofuels arena will improve environmental sustainability through the development of carbon neutral fuels, and produce a new domestic fuel source that will strengthen economic and homeland security. This project will generate genetic tools, strains, and network map data that will be made available to the biofuels research community. Further, many of these tools and strains will be of interest to biotechnology companies for direct commercialization. The project will directly train two doctoral graduate students and a number of undergraduate students in systems biology, a growing field with a need for trained personnel. In turn the doctoral students will utilize knowledge and actual data gleaned from this project as a teaching tool in a local bioenergy certificate program known as EDGE (Educating and Developing workers for the Green Economy). Graduates of this program have actively and successfully contributed to the growing green biotechnology industry of San Diego.
