title: Capture of carbon dioxide from ethanol fermentation by liquid absorption for use in biological production of succinic acid.
abstract: Previously, it was shown that the gas produced in an ethanol fermentor using either corn or barley as feedstock could be sparged directly into an adjacent fermentor as a feedstock for succinic acid fermentation using Escherichia coli AFP184. In the present investigation, it was demonstrated that the CO2 produced in a corn ethanol fermentor could be absorbed in a base solution and the resultant carbonate solution used both for pH control and supply of the CO2 requirement in succinic acid fermentation. Thus, the CO2 produced in a 5-L corn mash containing 30 wt% total solids was absorbed in a packed column containing 2 L of either 5 M NaOH, 5 M KOH, or 15 wt% NH4OH, and the resultant carbonate solutions were used for pH control in a succinic acid fermentor. The results obtained indicated no significant differences between succinic acid production in these experiments and when 2.5 M solutions of Na2CO3, K2CO3, and (NH4)2CO3 from commercial sources were used. In a commercial setting, the demonstrated capture of CO2 in liquid form will allow transportation of the carbonate solutions to locations not in the immediate vicinity of the ethanol plant, and excess carbonate salts can also be recovered as value-added products.
authors.affiliation: Sustainable Biofuels and Co-products Research Unit, Eastern Regional Research Center, Agricultural Research Service, USDA, Wyndmoor, PA, 19038, USA, john.nghiem@ars.usda.gov.
authors.forename: Nhuan P
authors.initials: NP
authors.lastname: Nghiem
authors.forename: Gerard E
authors.initials: GE
authors.lastname: Senske
mesh_terms: D000468:Alkalies; D018533:Biomass; D019149:Bioreactors; D057486:Carbon Cycle; D002245:Carbon Dioxide / Q000737:chemistry* / Q000378:metabolism; D002254:Carbonates / Q000737:chemistry* / Q000378:metabolism; D003470:Culture Media / Q000737:chemistry; D004926:Escherichia coli / Q000378:metabolism*; D000431:Ethanol / Q000378:metabolism*; D005285:Fermentation; D001467:Hordeum / Q000378:metabolism; D006863:Hydrogen-Ion Concentration; D019802:Succinic Acid / Q000378:metabolism*; D003313:Zea mays / Q000378:metabolism
chemical_list: D000468:Alkalies; D002254:Carbonates; D003470:Culture Media; D002245:Carbon Dioxide; D000431:Ethanol; D019802:Succinic Acid