Release Time:2019-07-01  Hits:

Indexed by: Journal Article

Date of Publication: 2019-05-20

Journal: SCIENCE OF THE TOTAL ENVIRONMENT

Included Journals: EI、SCIE、PubMed

Volume: 666

Page Number: 114-125

ISSN: 0048-9697

Key Words: Microbial electrosynthesis system; Cu-tolerant biofihn and plankton cell; CO2 fixation; Extracellular polymeric substances; Physiological activity; Variable cathode potential

Abstract: Simultaneous CLOD reduction (6.42 +/- 0.02 mg/L/h), acetate production (1.13 +/- 0.02 mg/L/h) from inorganic carbon (i.e., CO2 sequestration), and hydrogen evolution (0.0315 +/- 0.0005 m(3)/m(3)/d) were achieved in a Serratia marcescens Q1 catalyzed microbial electrosynthesis system (MES). The biofilms released increasing amounts of extracellular polymeric substances (EPS) with a higher compositional diversity and stronger Cu(II) complexation, compared to the plankton cells, at higher Cu(II) concentrations (up to 80 mg/L) and circuital currents (cathodic potential of -900 mV vs. standard hydrogen electrode (SHE)). Moreover, the biofilms reduced Cu(II) to Cu (0) more effectively than the plankton cells. At Cu(II) concentrations below 80 mg/L, the dehydrogenase activity in the biofilms was higher than in the plankton cells, and increased with circuital current, which was converse to the lower activities of catalase (CAT), superoxide dismutase (SOD) and antioxidative glutathione (GSH) in the biofilms than the plankton cells, although all these physiological activities were positively correlated with the concentration of Cu(II). This is the first study that evaluates the EPS constituents and the physiological activities of the biofilms and the plankton cells in the MESS, that favors the production of acetate from CO2 sequestration and the simultaneous reduction of CLOD from organics-barren waters contaminated with heavy metals. (C) 2019 Elsevier B.V. All rights reserved.