FIG 3.

In vivo reduction of CO₂ by C. acetobutylicum expressing the CODH/ACS complex or the CODH enzyme alone. Cells of C. acetobutylicum expressing the CODH/ACS complex or the CODH enzyme alone were grown on glucose (40 g/liter) in defined medium in sealed serum bottles with 10 lb/in² CO₂ and H₂ (20/80) in the headspace. A concentration of 50 mM [¹³C]bicarbonate was added to the sealed bottles. (A) Total nanomoles CO (¹²CO and ¹³CO) in each serum bottle (10 ml of liquid culture). (B) Percentage of ¹³CO in produced CO. There was no statistically significant difference in either the amount of CO produced or the percentage of ¹³C-labeling in CO (n = 4). Error bars indicate the standard error of four biological replicates.