Microorganisms Used in Syngas Fermentation
As this is a relatively new area of science a limited number of microorganisms are presently known for the fermentation of syngas to ethanol and other biofuels. Some of the most commonly used microorganisms that can produce a significant proportion of ethanol in the fermentation process are as follows:
Clostridium Ijungdahlii [14,15]
Clostridium carboxidivorans P7 [16]
Clostridium ragsdalei (also called Clostridium strain P11) [17-21] Clostridium autoethanogenum [22]
Peptostreptococcus products [23]
These microorganisms can proficiently operate in the pH 4.0 to 7.0 range, at temperatures close to ambient temperature, and utilize the reductive acetyl-CoA pathway for growth and production of acetic acid and ethanol as major products from CO, H2 and CO2 [11,24,15]. Alcohol and acetate yields from a selected sample of microorganisms and experimental conditions used in recent literature examples are shown in Table 12.1.