Aldehyde-deformylating oxygenase (ADO) is a key enzyme involved in the biosynthetic pathway of fatty alk(a/e)nes in cyanobacteria. However, cADO (cyanobacterial ADO) showed extreme low activity with the kcat value below 1 min−1 , which would limit its application in biofuel production. | Identification of residues important for the activity of aldehyde-deformylating oxygenase through investigation into the structure-activity relationship