S109: Metabolic Engineering of Synechococcus sp. PCC 7002 for Sustainable Production of Specialty Chemicals

Finding a sustainable alternative for today’s petrochemical industry is a major challenge facing society at large. To be sustainable, routes for converting carbon dioxide and light into organic compounds for use as both fuels and chemical building blocks must be identified, understood, and engineered. Advances in metabolic engineering, synthetic biology, and other biological engineering disciplines have expanded the scope of what can be produced in a living organism. As in other engineering disciplines, synthetic biologists want to apply a general understanding of science to construct complex systems from well-characterized parts. Once novel synthetic biological systems are constructed, they must be engineered to function inside evolving cells without negatively impacting the host’s physiology.

Using synthetic biology tools, we are engineering PCC7002 to produce a range of high-value chemicals. Here, I will discuss efforts to produce medium chain length alpha-olefins and organic acids in PCC7002. Our work focuses primarily on a novel polyketide pathway for converting acyl-ACPs to alpha-olefins (Mendez-Perez et. al, Applied and Environmental Microbiology, 2011). We have shown that this pathway is responsible for producing two 19-carbon olefins in PCC7002 that are essential for growth of PCC7002 under specific environmental conditions. We have begun to explore the auxiliary enzymes needed for their synthesis in effort to increase the titers of native olefins. In addition, we have begun to engineer the olefin synthase to accept alternative acyl-substrates by swapping individual domains. To facilitate these studies, we have developed metabolic engineering tools for PCC7002 including a novel counter-selection strategy and promoter libraries.