Photosynthetic production of glycerol by a recombinant cyanobacterium

•Recombinant Synechocystis harboring phosphoglycerol phosphatase produces glycerol.•Glycerol is produced at high levels.•Wild-type Synechocystis produces low amounts of glycerol under salt stress.•Glycerol production through the heterologous phosphatase and through salt stress is cumulative.•A sustainable route to glycerol production is provided that does not require arable land.

Cyanobacteria are prokaryotic organisms capable of oxygenic photosynthesis. Glycerol is an important commodity chemical. Introduction of phosphoglycerol phosphatase 2 from Saccharomyces cerevisiae into the model cyanobacterium Synechocystis sp. PCC6803 resulted in a mutant strain that produced a considerable amount of glycerol from light, water and CO2. Mild salt stress (200 mM NaCl) on the cells led to an increase of the extracellular glycerol concentration of more than 20%. Under these conditions the mutant accumulated glycerol to an extracellular concentration of 14.3 mM after 17 days of culturing.