Metabolic engineering of cyanobacteria for the synthesis of commodity products

• Metabolic engineering expands the list of products made with cyanobacteria.
• A limited number of branching points from intermediary metabolism are utilized.
• Metabolic engineering design principles are utilized and tailored to cyanobacteria.
• Carbon partitioning into product reaches almost 100% for some compounds.

Through metabolic engineering cyanobacteria can be employed in biotechnology. Combining the capacity for oxygenic photosynthesis and carbon fixation with an engineered metabolic pathway allows carbon-based product formation from CO2, light, and water directly. Such cyanobacterial ‘cell factories’ are constructed to produce biofuels, bioplastics, and commodity chemicals. Efforts of metabolic engineers and synthetic biologists allow the modification of the intermediary metabolism at various branching points, expanding the product range. The new biosynthesis routes ‘tap’ the metabolism ever more efficiently, particularly through the engineering of driving forces and utilization of cofactors generated during the light reactions of photosynthesis, resulting in higher product titers. High rates of carbon rechanneling ultimately allow an almost-complete allocation of fixed carbon to product above biomass.