title: Ethanol production during semi-continuous syngas fermentation in a trickle bed reactor using Clostridium ragsdalei.
abstract: An efficient syngas fermentation bioreactor provides a mass transfer capability that matches the intrinsic kinetics of the microorganism to obtain high gas conversion efficiency and productivity. In this study, mass transfer and gas utilization efficiencies of a trickle bed reactor during syngas fermentation by Clostridium ragsdalei were evaluated at various gas and liquid flow rates. Fermentations were performed using a syngas mixture of 38% CO, 28.5% CO2, 28.5% H2 and 5% N2, by volume. Results showed that increasing the gas flow rate from 2.3 to 4.6sccm increased the CO uptake rate by 76% and decreased the H2 uptake rate by 51% up to Run R6. Biofilm formation after R6 increased cells activity with over threefold increase in H2 uptake rate. At 1662h, the final ethanol and acetic acid concentrations were 5.7 and 12.3g/L, respectively, at 200ml/min of liquid flow rate and 4.6sccm gas flow rate.
authors.affiliation: Biosystems and Agricultural Engineering Department, Oklahoma State University, Stillwater, OK, USA.
authors.forename: Mamatha
authors.initials: M
authors.lastname: Devarapalli
authors.affiliation: Biosystems and Agricultural Engineering Department, Oklahoma State University, Stillwater, OK, USA. Electronic address: hasan.atiyeh@okstate.edu.
authors.forename: Hasan K
authors.initials: HK
authors.lastname: Atiyeh
authors.affiliation: Biosystems and Agricultural Engineering Department, Oklahoma State University, Stillwater, OK, USA.
authors.forename: John R
authors.initials: JR
authors.lastname: Phillips
authors.affiliation: Department of Chemical Engineering, Brigham Young University, Provo, UT, USA.
authors.forename: Randy S
authors.initials: RS
authors.lastname: Lewis
authors.affiliation: Biosystems and Agricultural Engineering Department, Oklahoma State University, Stillwater, OK, USA.
authors.forename: Raymond L
authors.initials: RL
authors.lastname: Huhnke
mesh_terms: D019342:Acetic Acid / Q000378:metabolism; D018441:Biofilms; D019149:Bioreactors; D002245:Carbon Dioxide / Q000737:chemistry / Q000378:metabolism*; D002248:Carbon Monoxide / Q000737:chemistry / Q000378:metabolism*; D003013:Clostridium / Q000378:metabolism*; D000431:Ethanol / Q000378:metabolism*; D005285:Fermentation; D006859:Hydrogen / Q000737:chemistry / Q000378:metabolism*; D007700:Kinetics
chemical_list: D002245:Carbon Dioxide; D000431:Ethanol; D002248:Carbon Monoxide; D006859:Hydrogen; D019342:Acetic Acid
keywords: Clostridium ragsdalei; Ethanol; Mass transfer; Semi-continuous syngas fermentation; Trickle bed reactor