Biodiesel production using blue-green cyanobacterium Synechococcus elongatus PCC 7942

Due to concerns about global climate change and diminishing supplies of petroleum, there is a need to develop a clean sustainable alternative. The two main alternative fuels are bioethanol and biodiesel. Production of these biofuels using cyanobacteria is a new promising development. I describe the initial rational engineering of S. elongatus PCC 7942 for the production of biodiesel precursors. Three strains were constructed Se:T, Se:∆A and Se:∆A+T. These were subsequently characterized with regard to their intracellular and extracellular fatty acid (FA) profile, intracellular hydrocarbon profile and effect on growth. This provided a comprehensive picture of early effects caused by the introduced mutations. I describe further rational optimization of free FA production by overexpressing the native acetyl-CoA carboxylase (ACCase) from S. elongatus PCC 7942. Introduction of the ACCase in wild type S. elongatus PCC 7942 alone did not cause an increase in intracellular FAs. However, in strain Se:∆A+T, there was a significant increase in the amount of extracellular FAs. I describe the initial inverse metabolic engineering of S. elongatus PCC 7942 for the production of biodiesel precursors. Our results suggest that the GTP-binding protein Era is a promising target to further rational engineering to improve the production of biofuel precursors.