Experimental evaluation of the influential factors of acetate production driven by a DC power system via CO2 reduction through microbial electrosynthesis

Tian-Shun Song,Haoqi Wang,Guangrong Wang,Jingjing Xie,Qiong Huang

doi:10.1186/s40643-019-0265-5

Abstract

Microbial electrosynthesis (MES) is potentially useful for the biological conversion of carbon dioxide into value-added chemicals and biofuels. The study evaluated several limiting factors that affect MES performance. Among all these factors, the optimization of the applied cell voltage, electrode spacing, and trace elements in catholytes may significantly improve the MES performance. MES was operated under the optimal condition with an applied cell voltage of 3 V, an electrode spacing of 8 cm, 2× salt solution, and 8× trace element of catholyte for 100 days, and the maximum acetate concentration reached 7.8 g L−1. The microbial community analyses of the cathode chamber over time showed that Acetobacterium, Enterobacteriaceae, Arcobacter, Sulfurospirillum, and Thioclava were the predominant genera during the entire MES process. The abundance of Acetobacterium first increased and then decreased, which was consistent with that of acetate production. These results provided useful hints for replacing the potentiostatic control of the cathodes in the future construction and operation of MES. Such results might also contribute to the practical operation of MES in large-scale systems.

Highlights

The current worldwide emission of greenhouse gases, such as C O2, is mainly attributed to the use of fossil fuels (O’Neill and Oppenheimer 2002)
Effect of the cell voltage The production rate of acetate was optimized on the basis of a reaction time of 14 days
The results show that a high concentration of acetate can be obtained using Microbial electrosynthesis (MES) with a DC power source

Summary

Introduction

The current worldwide emission of greenhouse gases, such as C O2, is mainly attributed to the use of fossil fuels (O’Neill and Oppenheimer 2002). Researchers should develop the cost-effective C O2 transformation technologies to balance the increasing energy demand with the need to economically reduce C O2 emissions. In comparison with pure strains (Nie et al 2013; Nevin et al 2010; Zhang et al 2013), mixed culture (Dong et al 2018; Marshall et al 2013; Modestra and Mohan 2017; Jourdin et al 2014; Patil et al 2015; Song et al 2017, 2018) is possibly more suitable for the commercialization of MES because it has better resistance to environmental disturbances, high biomass, Song et al Bioresour. The bio-production rate of acetate should reach at least 4550 mol per day to achieve economic feasibility. This analysis indirectly indicates that MES can be scaled up as high-value chemicals producers

Methods

Results

Conclusion