Wednesday, October 19, 2011
Exhibit Hall B (Minneapolis Convention Center)
Syngas fermentation involves complex biochemical reactions of gaseous substrates to produce liquid products such as ethanol, butanol and acetic acid using special group of acetogenic microorganisms. Ethanol productivity and syngas conversion efficiency are severely affected by the low solubility of CO and H2, the primary components of syngas, in the fermentation media. One way to improve ethanol productivity and syngas conversion efficiency is to increase the rate at which CO and H2 are transferred into the fermentation media. A trickle bed reactor (TBR) can enhance gas-liquid mass transfer efficiency by minimizing the liquid resistance to mass transfer because of a very thin liquid film that is in contact with the gas. Results on mass transfer characteristics of a 1L TBR with two packing materials and syngas fermentations using “Clostridium ragsdalei” strain P11 will be presented. A counter-current flow of liquid and gas configuration in the TBR were used. The optimal conditions based on the highest gas-liquid mass transfer coefficients for CO and H2 were considered in syngas fermentation experiments. A commercial syngas mixture containing 40% CO, 30% CO2, 30% H2, by volume, was fed to the TBR at 37°C. Cell growth rates, ethanol and acetic acid production rates, CO and H2 consumption rates were determined.