Biological conversion of carbon monoxide to ethanol: Effect of pH, gas pressure, reducing agent and yeast extract

► Initial total pressure and reducing agent had positive effects on ethanol production. ► Initial pH and yeast extract had a negative impact on ethanol production. ► All factors and interactions were statistically significant for ethanol production. ► A high ethanol production (0.65 g/L) was obtained using Clostridium autoethanogenum.