In-situ carboxylate recovery and simultaneous pH control with tailor-configured bipolar membrane electrodialysis during continuous mixed culture fermentation
Arslan, D. ; Zhang, Y. ; Steinbusch, K.J.J. ; Diels, L. ; Hamelers, Hubertus V.M. ; Buisman, C.J.N. ; Wever, H. de - \ 2017
Separation and Purification Technology 175 (2017). - ISSN 1383-5866 - p. 27 - 35.
Bipolar membrane - Electrodialysis - Fermentation - ISPR - Short chain carboxylates
Anaerobic fermentation of organic waste streams by mixed culture generates a mixture of short chain carboxylic acids. To avoid inhibitory effects of the acids or their consumption in internal conversion reactions in the mixed culture environment, in-situ recovery of acids can be beneficial. In this study, electrodialysis with bipolar membranes (EDBM) was applied to a mixed culture fermentation on organic waste streams using a novel EDBM stack with “direct contact” operation mode. We could demonstrate simultaneous recovery of carboxylates from the fermenter by the EDBM stack while in-situ generation and transport of hydroxyl ions to the fermenter allowed direct pH control. Experiments showed productivity increase after EDBM coupling to the fermenter, and complete elimination of external base consumption. It was also observed that EDBM was able to drive the mixed culture fermentation towards acetate and propionate type of carboxylates.
Product Specificity Influenced by Catholyte Conditions during the Microbial Electrosynthesis Process CO2 to Acetate
Bajracharya, S. ; Mohanakrishna, G. ; Vanbroekhoven, K. ; Wever, H. De; Pant, D. ; Buisman, C.J.N. ; Strik, D. - \ 2016
Chemie Ingenieur Technik 88 (2016)9. - ISSN 0009-286X - p. 1253 - 1253.
Integrated Product Separation in Bioelectrochemical CO2 Reduction for Improved Process Efficiency
Bajracharya, S. ; Vanbroekhoven, K. ; Wever, H. De; Strik, D. ; Buisman, C. ; Pant, Deepak - \ 2016
Chemie Ingenieur Technik 88 (2016)9. - ISSN 0009-286X - p. 1255 - 1256.
Selective short-chain carboxylates production : A review of control mechanisms to direct mixed culture fermentations
Arslan, D. ; Steinbusch, K.J.J. ; Diels, L. ; Hamelers, H.V.M. ; Strik, D.P.B.T.B. ; Buisman, C.J.N. ; Wever, H. De - \ 2016
Critical Reviews in Environmental Science and Technology 46 (2016)6. - ISSN 1064-3389 - p. 592 - 634.
Biomass conversion - carboxylates - mixed culture fermentation - operational parameters - organic waste - volatile fatty acids
Anaerobic digestion of organic residual streams can be directed to produce carboxylates such as acetate, propionate, and n-butyrate, which can be either directly used in industry or converted into other valuable compounds. This paper reviews the studies working with mixed culture conversion of organic substrates toward carboxylates. It draws connections between standard fermentation parameters and the carboxylate product concentrations and composition. The use of more concentrated carbohydrate-rich substrates, at longer residence times and at neutral pH ranges, stimulates total acid production. When increasing pH to the neutral range, acetate and propionate fractions are elevated. High propionate concentrations and fractions are infrequently reported and mainly appear on high-protein-containing feedstock. High n-butyrate fraction <70% is usually found when pH > 6, at longer retention times or organic loading rates, under CO2 atmosphere or on substrates with high lactate concentrations. The review concludes with prospects for further developments related to the carboxylate platform.
Selective carboxylate production by controlling hydrogen, carbon dioxide and substrate concentrations in mixed culture fermentation
Arslan, D. ; Steinbusch, K.J.J. ; Diels, L. ; Wever, H. de; Hamelers, H.V.M. ; Buisman, C.J.N. - \ 2013
Bioresource Technology 136 (2013). - ISSN 0960-8524 - p. 452 - 460.
sequencing batch reactor - biohydrogen production - biological production - waste-water - bacteria - glucose - acid - bioconversion - butyrate - caproate
This research demonstrated the selective production of n-butyrate from mixed culture by applying 2 bar carbon dioxide into the headspace of batch fermenters or by increasing the initial substrate concentration. The effect of increasing initial substrate concentration was investigated at 8, 13.5 and 23 g COD/L with potato processing waste stream. Within 1 week of incubation, n-butyrate fraction selectively increased up to 83% by applying 2 bar hydrogen or 78% by applying carbon dioxide into the headspace whereas it was only 59% in the control reactor. Although the fraction of n-butyrate was elevated, the concentration remained lower than in the control. Both the highest concentration and fraction of n-butyrate were observed under the highest initial substrate concentration without headspace addition. The concentration was 10 g COD/L with 73% fraction. The operational conditions obtained from batch experiments for selective n-butyrate production were validated in a continuous process.
Effect of hydrogen and carbon dioxide on carboxylic acids patterns in mixed culture fermentation
Arslan, D. ; Steinbusch, K.J.J. ; Diels, L. ; Wever, H. De; Buisman, C.J.N. ; Hamelers, H.V.M. - \ 2012
Bioresource Technology 118 (2012). - ISSN 0960-8524 - p. 227 - 234.
acidogenic fermentation - biohydrogen production - anaerobic-bacteria - waste-water - fatty-acids - degradation - communities - inhibition - hydrolysis - industrial
This study investigated the carboxylate spectrum from mixed culture fermentation of three organic waste streams after supplying 2 bar hydrogen and carbon dioxide or a mixture of these two gases to the headspace. Under any modified headspace, propionate production was ceased and butyrate, caproate and the total carboxylate concentrations were higher than in the reactors with N2 headspace (control). Production of one major compound was achieved under hydrogen and carbon dioxide mixed headspace after 4 weeks of incubation. Both the highest acetate concentration (17.4 g COD/l) and the highest fraction (87%) were observed in reactors with mixed hydrogen and carbon dioxide headspace independent of the substrate used. In the control reactor, acetate made up maximum 67% of the total products. For other products, the highest concentration and fraction were seldom observed together. Selective butyrate production reaching a 75% fraction was found under the carbon dioxide headspace on the carbohydrate rich waste.