Bioethanol Synthesis for Liquid Fuel Using Rhodospirillum rubrum and Clostridium ljungdahlii

Synthesis gas was used to convert low value waste gas to clean fuel such as hydrogen. Non- sulfur autotrophic bacterium, Rhodospirillum rubrum and Clostridium ljungdahlii were used in the bioconversion of waste gas to liquid fuel. Biological production of hydrogen from synthesis gas has been carried out in a batch and continuous cultures. Phototrophic anaerobic bacterium, Rhodospirillum rubrum was used to oxidize CO and water to CO2 and hydrogen in batch and continuous fermentation. The bacteria were grown under anaerobic condition in liquid media; acetate was used as carbon source in presence of synthesis gas. In batch culture all process parameters and biological conditions were investigated, effect of substrate in liquid media and pH were studied to maximize and enhance hydrogen production. Clostridium ljungdahlii are strictly anaerobic autotrophic bacteria, were grown on synthesis gas to produce hydrogen, acetate and ethanol from gaseous substrates. C. ljungdahlii was also grown on a various concentrations of carbon monoxide with synthesis gas.

Keywords:

Synthesis gas , Rhodospirillum rubrum , Clostridium ljungdahlii , Ethanol , Acetate