Propane produced in pathway-engineered Δahr/ΔyqhD single or double knockout
strains and the effects of co-expressing a ferredoxin electron donating system. Propane production in the pathway-engineered ΔyqhD knockout cells with wild-type ADO or with the ADOA134F variant enzyme is shown (A). The ΔyqhD knockout strains were either engineered to contain the atoB-TPC7 route (indicated by red colour) or the nphT7-TPC7 route (indicated by green colour). Wild-type ADO or the ADOA134F variant enzyme was co-expressed in the engineered cells either in combination with or without ferredoxin (Fdx) from Synechocystis sp. PCC 6803 (B). A detailed protocol for the pathway engineering and propane detection is included in the ‘Materials and methods’ section and supporting information (Additional file 1: Figure S6). Error bars are standard deviation (n = 4). ADO, aldehyde deformylating oxygenase.