Reduction Of Cu(?)and Simultaneous Production Of Acetate From Inorganic Carbon By S.Marcescens Biofilms And Plankton Cells In Microbial Electrosynthesis Systems

As a new sustainable technology,bioelectrochemical systems provide a new method for removing heavy metal ions and using inorganic carbon to produce acetate.In this study,Serratia marcescens Q1 was used as cathode catalyst to explore the reduction of Cu???and simultaneous production of acetate in microbial electrosynthesis systems?MESs?.This is the first study that evaluates the EPS constituents and the physiological activities of the biofilms and the plankton cells in the MES and it favors the production of acetate from CO₂ sequestration and the simultaneous reduction of Cu???from organics-barren waters contaminated with heavy metals.Simultaneous Cu???reduction?6.42±0.02 mg/L/h?,acetate production?1.13±0.02mg/L/h?from inorganic carbon,and hydrogen evolution?0.0315±0.0005 m³/m³/d?were achieved in a Serratia marcescens Q1 catalyzed MESs.The biofilms released increasing amounts of extracellular polymeric substances?EPS?with a higher compositional diversity and stronger Cu???complexation,compared to the plankton cells.The presence of Cu???and an appropriate increase in current also stimulate the secretion of EPS and improve its binding ability with Cu???.The physiological activities of GSH,SOD,CAT and dehydrogenase were correlated to the rates of Cu???removal and acetate production in the metallurgical MESs.The dehydrogenase activity in the biofilms was higher than that in the plankton cells,and increased with circuital current,which was converse to the lower activities of catalase CAT,SOD and GSH in the biofilms than the plankton cells.