(425c) Metabolic Engineering of Fatty Acid Pathways In Synechocystis PCC 6803 for Biofuel Production

Cyanobacteria are photosynthetic microorganisms that can consume carbon dioxide and convert them into useful products such as alcohols, fatty acids, and biopolymers. The cyanobacterium Synechocystis PCC6803 is a good candidate for biofuel production because it has a well established molecular biology toolbox for genetic manipulation and its complete genome has been sequenced. There are two variants of Synechocystis 6803; one being the Glucose Tolerant (GT) mutant strain and the other being the wild type (WT) strain. The methods for gene knockouts and insertions developed thus far have primarily focused on the GT mutant strain. We want to utilize the WT strain because it has a higher growth rate compared to the GT strain. To engineer the WT strain, we developed a novel method for counter selection using the general protein synthesis inhibitor mazF from E.coli. We demonstrate the effectiveness of our method by inserting genes to manipulate the fatty acid biosynthesis pathway in the WT strain of Synechocystis.

                 Prokaryotic fatty acid biosynthesis is a well studied pathway especially in E.coli. In Synechocystis, the pathway generally functions to synthesize fatty acid chains which are mostly used for the formation and maintenance of the bacterial cell membrane.  The fatty acid pathway can be manipulated to produce a variety of biochemicals and biofuels that could replace gasoline and diesel.  We are particularly interested in utilizing the techniques of metabolic engineering and synthetic biology to engineer the WT strain of Synechocystis for hydrocarbon production.  This talk will focus on our efforts to date.