Synergetic interaction of magnetic field and loaded magnetite for enhanced acetate production in biocathode of microbial electrosynthesis system

Abstract

Magnetic field (MF, 200 mT) and Fe3O4 (26 g/m2) are simultaneously employed to enhance acetate production from bicarbonate reduction in Serratia marcescens catalyzed cathode of microbial electrosynthesis system (MES), reaching 8.5 mM at an operational time of 9 d, higher than the controls by 1.7-time (Fe3O4 only), 1.8-fold (MF only), and 2.3-time (neither Fe3O4 nor MF). This confirms synergetic interaction of the MF and Fe3O4 for enhanced acetate production in the MES. The presence of MF and Fe3O4 induces the S. marcescens physiologically releasing more extracellular polymeric substances with a compositional diversity and containing more c-type cytochromes for facilitating extracellular electron transfer for efficient acetate production. Moreover, the favorable MF for less shedding (approximate 40%) of Fe3O4 from the biocathode, also contributes to the efficient MES. This study provides a feasible strategy of the Fe3O4 and MF for efficient acetate production from bicarbonate reduction in the MES.