Cyanobacterial genes used for synthetic biology "Fit Coli"
From within the New Yorker post titled Synthetic Life After G.M.O.s
To combat the diet-pill menace, her team had decided to design a gut-dwelling E. coli bacterium with an increased ability to absorb certain long-chain fatty acids, such as saturated stearic acid, which is abundant in animal fat, and convert them into unsaturated alpha-linolenic acid (ALA), which is found in plant oils. Their new organism was called Fit Coli.
The team had begun by cloning the native genes that allow E. coli to soak up stearic acid in the gut. These cloned sequences, known as a cassette, were slotted into a fresh E. coli cell, thereby boosting its fat-absorbing powers. Now it was necessary to give the cell the ability to convert the surfeit stearic acid into ALA, which meant inserting three chunks of synthetic DNA, inspired by freshwater cyanobacteria but rewritten to function inside E. coli.
ALA is C18:3. Stearic acid is octadecanoic acid, so that the conversion of stearic acid to ALA (by the cyanobacteria) involves removal of hydrogen.
See also US application 20140051131 to Algaecytes Limited.