Controlling Ethanol Use in Chain Elongation by CO2 Loading Rate
| Autor: | David P.B.T.B. Strik, Tim Hoogstad, Mark Roghair, Peer H. A. Timmers, Marieke E. Bruins, Cees J.N. Buisman, Caroline M. Plugge, Ruud A. Weusthuis |
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| Rok vydání: | 2018 |
| Předmět: |
Bio Process Engineering
Biobased Chemistry and Technology 020209 energy 02 engineering and technology 010501 environmental sciences Microbiology 01 natural sciences Article chemistry.chemical_compound Bioreactors Volatile fatty acids Microbiologie 0202 electrical engineering electronic engineering information engineering Bioreactor Life Science Environmental Chemistry Food science VLAG 0105 earth and related environmental sciences chemistry.chemical_classification WIMEK Ethanol General Chemistry Carbon Dioxide Fatty Acids Volatile BBP Bioconversion chemistry Biofuel Carbon dioxide Propionate Loading rate Environmental Technology Milieutechnologie Elongation Biotechnology |
| Zdroj: | Environmental Science and Technology 52 (2018) 3 Environmental Science & Technology Environmental Science and Technology, 52(3), 1496-1505 |
| ISSN: | 1520-5851 0013-936X |
| Popis: | Chain elongation is an open-culture biotechnological process which converts volatile fatty acids (VFAs) into medium chain fatty acids (MCFAs) using ethanol and other reduced substrates. The objective of this study was to investigate the quantitative effect of CO2 loading rate on ethanol usages in a chain elongation process. We supplied different rates of CO2 to a continuously stirred anaerobic reactor, fed with ethanol and propionate. Ethanol was used to upgrade ethanol itself into caproate and to upgrade the supplied VFA (propionate) into heptanoate. A high CO2 loading rate (2.5 LCO2·L–1·d–1) stimulated excessive ethanol oxidation (EEO; up to 29%) which resulted in a high caproate production (10.8 g·L–1·d–1). A low CO2 loading rate (0.5 LCO2·L–1·d–1) reduced EEO (16%) and caproate production (2.9 g·L–1·d–1). Heptanoate production by VFA upgrading remained constant (∼1.8 g·L–1·d–1) at CO2 loading rates higher than or equal to 1 LCO2·L–1·d–1. CO2 was likely essential for growth of chain elongating microorganisms while it also stimulated syntrophic ethanol oxidation. A high CO2 loading rate must be selected to upgrade ethanol (e.g., from lignocellulosic bioethanol) into MCFAs whereas lower CO2 loading rates must be selected to upgrade VFAs (e.g., from acidified organic residues) into MCFAs while minimizing use of costly ethanol. |
| Databáze: | OpenAIRE |
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