Building Metabolic Engineering Tools to Better Understanding Product Production from Microbial Sources: Using the Cyanobacterium Synechocystis Sp. PCC 6803 for Astaxanthin Production

Product production in microorganisms has great potential to fulfill many industries requirements for biologically derived molecules. Because of the simplicity of bacteria, cyanobacteria make good candidates as a platform for product production. For photosynthetic organisms to fulfill this potential, gene expression will need to be manipulated, controlled, and ultimately managed within the cell. Currently, metabolic engineers utilize molecular tools that are poorly understood and therefore contribute to inconsistent results and product titers. The objective of my research is to better understand how commonly utilized promoter constructs operate during typical environmental conditions within cyanobacterial cells.

Using the photosynthetic cyanobacterium Synechocystis sp. PCC 6803, we have been able to successfully quantify gene expression from several suites of promoter constructs.  We have developed and tested variants based on the commonly used E. coli tac suite of promoters, which includes an inducible construct capable of inducing gene expression in Synechocystis.   Additionally, we have quantified expression of promoters commonly believed to control gene expression during circadian rhythms.  As a proof of concept, we have begun to use these promoter constructs to engineer the carotenoid biosynthesis pathway found in Synechocystis. This poster will detail the specifics related to our research.