ABSTRACT
The present study put forth with the fundamental objective to the exploration of exoelectrogens from theextremophilic environment and to investigate the electricity generation from them. A total of 20 bacterialcultures were isolated, from which BW2(1) was selected for the further investigation of the microbial fuelcell (MFC). The experimental results performed that the strain Bacillus alkalogaya BW2(1) was capable ofutilizing organic acids and sugars as electron donors to generate electricity. The MFC was constructed and theelectricity generation was measured after various intervals using various parameters and substrates, 937 mVelectricity was generated after 1 hour, but after 48 hours the electricity generation dramatically decreases to570 mV. The effect of pH on MFC was also studied, pH enhanced electricity, indicating the requirement ofpH for bacterium BW2(1). This is a valuable information for bioelectricity production and optimization fromB. alkalogaya BW2(1) has bright future toward the improvement and production of bioelectricity for entirelynew areas of industrial and biotechnological applications.
ABSTRACT
The secondary metabolites, phenazine products, produced by Pseudomonas aeruginosa can mediate the electrons transfer in microbial fuel cells (MFCs). How increase the total electricity production in MFCs by improving the characteristics of Pseudomonas aeruginosa is one of research hot spots and problems. In this study, P. aeruginosa strain SJTD-1 and its knockout mutant strain SJTD-1 (ΔmvaT) were used to construct MFCs, and the discharge processes of the two MFCs were analyzed to determine the key factors to electricity yields. Results indicated that not only phenazine but also the viable cells in the fermentation broth were essential for the discharge of MFCs. The mutant strain SJTD-1 (ΔmvaT) could produce more phenazine products and continue discharging over 160 hours in MFCs, more than that of the wild-type SJTD-1 strain (90 hours discharging time). The total electricity generated by SJTD-1 (ΔmvaT) strain could achieve 2.32 J in the fermentation process, much higher than the total 1.30 J electricity of the wild-type SJTD-1 strain. Further cell growth analysis showed that the mutant strain SJTD-1 (ΔmvaT) could keep a longer stationary period, survive much longer in MFCs and therefore, discharge more electron than those of the wild-type SJTD-1 strain. Therefore, the cell survival elongation of P. aeruginosa in MFCs could enhance its discharging time and improve the overall energy yield. This work could give a clue to improve the characteristics of MFCs using genetic engineering strain, and could promote related application studies on MFCs.
ABSTRACT
Electroactive bacteria, including electrigenic bacteria (exoelectrogens) and electroautotrophic bacteria, implement microbial bioelectrocatalysis processes via bi-directional exchange of electrons and energy with environments, enabling a wide array of applications in environmental and energy fields, including microbial fuel cells (MFC), microbial electrolysis cells (MEC), microbial electrosynthesis (MES) to produce electricity and bulk fine chemicals. However, the low efficiency in the extracellular electron transfer (EET) of exoelectrogens and electrotrophic microbes limited their industrial applications. Here, we reviewed synthetic biology approaches to engineer electroactive microorganisms to break the bottleneck of their EET pathways, to achieve higher efficiency of EET of a number of electroactive microorganisms. Such efforts will lead to a breakthrough in the applications of these electroactive microorganisms and microbial electrocatalysis systems.