BioChem - DOS

Long-term operation of electro-biocatalytic reactor for carbon dioxide transformation into organic molecules

Bioresource technology : biomass, bioenergy, biowastes, conversion technologies, biotransformations, production technologies

Srikanth, Sandipam; Kumar, Manoj; Singh, Dheer; Singh, M.P.; Puri, S.K.; Ramakumar, S.S.V.

<P><B>Abstract</B></P> <P>Electro-biocatalytic reactor was operated using selectively enriched mixed culture biofilm for about 320 days with CO<SUB>2</SUB>/bicarbonate as C-source. Biocathode consumed higher current (&minus;16.2 &plusmn; 0.3 A/m<SUP>2</SUP>) for bicarbonate transformation yielding high product synthesis (0.74 g/l/day) compared to CO<SUB>2</SUB> (&minus;9.5 &plusmn; 2.8 A/m<SUP>2</SUP>; 0.41 g/l/day). Product slate includes butanol and butyric acid when CO<SUB>2</SUB> gets transformed but propionic acid replaced both when bicarbonate gets transformed. Based on electroanalysis, the electron transfer might be H<SUB>2</SUB> mediated along with direct transfer under bicarbonate turnover conditions, while it was restricted to direct under CO<SUB>2</SUB>. Efficiency and stability of biofilm was tested by removing the planktonic cells, and also confirmed in terms of Coulombic (85&ndash;97%) and carbon conversion efficiencies (42&ndash;48%) along with production rate (1.2&ndash;1.7 kg/m<SUP>2</SUP> electrode) using bicarbonate as substrate. Selective enrichment of microbes and their growth as biofilm along with soluble CO<SUB>2</SUB> have helped in efficient transformation of CO<SUB>2</SUB> up to C4 organic molecules.</P> <P><B>Highlights</B></P> <P> <UL> <LI> Electro-biocatalytic CO<SUB>2</SUB> transformation to organics was studied for 320 days. </LI> <LI> Stabilized biocathode of selectively enriched culture was studied for electro-synthesis. </LI> <LI> CO<SUB>2</SUB> availability in soluble form dictated the product slate. </LI> <LI> Electron transfer is possibly H<SUB>2</SUB> mediated and DET with bicarbonate but restricted to DET with CO<SUB>2</SUB>. </LI> <LI> CE was high irrespective of carbon nature but CCE significantly varied for CO<SUB>2</SUB> and bicarbonate. </LI> </UL> </P>

2018

Elsevier

0960-8524

265

pp.66-74

10.1016/j.biortech.2017.12.075

http://click.ndsl.kr/servlet/OpenAPIDetailView?keyValue=05787966&target=NART&cn=NART85395732

Microbial electrosynthesis (MES); Bio-electrochemical system (BES); CO2 capture and reduction; Butanol; Butyric acid