Growth, headspace pressure change and metabolite profiles of C. autoethanogenum WT (black circles), aor1 KO (red triangles), aor2 KO (green squares), and aor1+2 KO strains (blue diamonds) on 200 kPa CO. (A) Growth profile; (B) Change in headspace pressure from start to end of cultivation; (C) Acetate profile; (D) Ethanol profile; (E) 2,3-Butanediol profile; and (F) Lactate profile; For each strain n =4, except for aor2 KO n =3; Error bars = s.e.m. (For interpretation of the references to color in this figure legend, the reader is referred to the web version of this article.)