TY - JOUR
T1 - Long-term operation of microbial electrosynthesis cell reducing CO2 to multi-carbon chemicals with a mixed culture avoiding methanogenesis
AU - Bajracharya, Suman
AU - Yuliasni, Rustiana
AU - Vanbroekhoven, Karolien
AU - Buisman, Cees J.N.
AU - Strik, David P.B.T.B.
AU - Pant, Deepak
PY - 2017
Y1 - 2017
N2 - In microbial electrosynthesis (MES), CO2 can be reduced preferably to multi-carbon chemicals by a biocathode-based process which uses electrochemically active bacteria as catalysts. A mixed anaerobic consortium from biological origin typically produces methane from CO2 reduction which circumvents production of multi-carbon compounds. This study aimed to develop a stable and robust CO2 reducing biocathode from a mixed culture inoculum avoiding the methane generation. An effective approach was demonstrated based on (i) an enrichment procedure involving inoculum pre-treatment and several culture transfers in H2:CO2 media, (ii) a transfer from heterotrophic to autotrophic growth and (iii) a sequential batch operation. Biomass growth and gradual acclimation to CO2 electro-reduction accomplished a maximum acetate production rate of 400 mg Lcatholyte − 1 d− 1 at − 1 V (vs. Ag/AgCl). Methane was never detected in more than 300 days of operation. Accumulation of acetate up to 7–10 g L− 1 was repeatedly attained by supplying (80:20) CO2:N2 mixture at − 0.9 to − 1 V (vs. Ag/AgCl). In addition, ethanol and butyrate were also produced from CO2 reduction. Thus, a robust CO2 reducing biocathode can be developed from a mixed culture avoiding methane generation by adopting the specific culture enrichment and operation procedures without the direct addition of chemical inhibitor.
AB - In microbial electrosynthesis (MES), CO2 can be reduced preferably to multi-carbon chemicals by a biocathode-based process which uses electrochemically active bacteria as catalysts. A mixed anaerobic consortium from biological origin typically produces methane from CO2 reduction which circumvents production of multi-carbon compounds. This study aimed to develop a stable and robust CO2 reducing biocathode from a mixed culture inoculum avoiding the methane generation. An effective approach was demonstrated based on (i) an enrichment procedure involving inoculum pre-treatment and several culture transfers in H2:CO2 media, (ii) a transfer from heterotrophic to autotrophic growth and (iii) a sequential batch operation. Biomass growth and gradual acclimation to CO2 electro-reduction accomplished a maximum acetate production rate of 400 mg Lcatholyte − 1 d− 1 at − 1 V (vs. Ag/AgCl). Methane was never detected in more than 300 days of operation. Accumulation of acetate up to 7–10 g L− 1 was repeatedly attained by supplying (80:20) CO2:N2 mixture at − 0.9 to − 1 V (vs. Ag/AgCl). In addition, ethanol and butyrate were also produced from CO2 reduction. Thus, a robust CO2 reducing biocathode can be developed from a mixed culture avoiding methane generation by adopting the specific culture enrichment and operation procedures without the direct addition of chemical inhibitor.
KW - Autotrophic bioproduction
KW - Biocathode
KW - CO reduction
KW - Microbial electrosynthesis
KW - Wood-Ljungdahl pathway
U2 - 10.1016/j.bioelechem.2016.09.001
DO - 10.1016/j.bioelechem.2016.09.001
M3 - Article
AN - SCOPUS:84994406842
VL - 113
SP - 26
EP - 34
JO - Bioelectrochemistry
JF - Bioelectrochemistry
SN - 1567-5394
ER -