Ethanol production during semi-continuous syngas fermentation in a trickle bed reactor using Clostridium ragsdalei. (June 2016)

• Record Type: Journal Article
• Authors: Devarapalli, Mamatha; Atiyeh, Hasan K.; Phillips, John R.; Lewis, Randy S.; Huhnke, Raymond L.
• Is Part Of: Bioresource technology. Volume 209(2016)
• Page Start: 56
• Page End: 65
• Publication Date: 2016-06
• Subjects: Semi-continuous syngas fermentation -- Clostridium ragsdalei -- Ethanol -- Trickle bed reactor -- Mass transfer; Biomass -- Periodicals; Biomass energy -- Periodicals; Bioremediation -- Periodicals; Agricultural wastes -- Periodicals; Factory and trade waste -- Periodicals; Organic wastes -- Periodicals; Bioénergie -- Périodiques; Déchets agricoles -- Périodiques; Déchets industriels -- Périodiques; Déchets organiques -- Périodiques; Déchets (Combustible) -- Périodiques; 662.88
• DOI: 10.1016/j.biortech.2016.02.086
• Languages: English
• ISSNs: 0960-8524

Abstract

Highlights: Biofilm formation in TBR resulted in two fold improvement in H2 uptake. Doubling gas flow rate increased CO and H2 uptake by over 80% in run R10 than in R2. Co-current flow reduced flooding and gas bypass occurred in counter-current mode. Maximum ethanol production rate of 0.80 mmol/L h was achieved in co-current flow. 5.7 g/L of ethanol and 12.3 g/L of acetic acid were produced with co-current flow. 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 4.6 sccm 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 1662 h, the final ethanol and acetic acid concentrations were 5.7 and 12.3 g/L, respectively, at 200 ml/min of liquid flow rate and 4.6 sccm gas flow rate.