Engineering neutral lipid synthesis in cyanobacteria for biofuel production

We use the cyanobacterium Synechococcus elongatus as a model to implement and improve pathways for neutral lipid biosynthesis (triglycerides and wax esters) in photosynthetic bacteria.  Optimization of these pathways requires manipulation of multiple variables, notably the natural diversity of enzymes that catalyze each essential step, the level of enzyme expression, and the subcellular localization of the exogenous biosynthetic pathway.  We will discuss how we’ve addressed these considerations and engineered continuously growing Synechococcus to produce wax esters and other intracellular lipids at 15-20% of biomass.  Further optimization of these pathways can be achieved by improving upstream steps that provide limiting metabolic resources.  We will highlight our work to increase photosynthetic efficiencies by reducing wasteful, photochemically non-productive absorbtion of photons by the phycobilisome light harvesting complex.