Halophilic starch degrading bacteria isolated from Sambhar Lake, India, as potential anode catalyst in microbial fuel cell: A promising process for saline water treatment

Understanding the cumulative effects of salinity, temperature and inoculation size for the design of optimal halothermotolerant bioanodes from hypersaline sediments

“…The integration of microbial catalysis with electrochemistry has given rise to several innovative processes, broadly known as bioelectrochemical systems (BES), with potential energy, environmental and industrial applications such as electricity generation, hydrogen production, wastewater treatment, pollutant removal and biomolecule synthesis [1,2,3,4,5]. In BES, the efficiency of bioanodes, in terms of electron exchange kinetics, ability to recover electrons from soluble molecules and, finally, robustness, is the key to considering their industrial exploitation [2,6].The apparent rates of electron transfer of bioanodes have greatly improved and, today, it has become possible to obtain very high current densities (greater than several tens of A/m 2 ) by using anodes of different materials, with different geometrical designs, and with chemical, thermal or electrochemical surface treatments or coatings [6,7,8]. Along these lines, Chen et al obtained a current density of up to 390 A/m 2 at 0.39 V/SHE by using multilayer structure bioanodes for the oxidation of acetate [9].…”

“…Some halophilic and/or thermophilic bacterial species isolated from extreme natural or industrial environments have been reported to display electroactive properties [19,20]. In particular, sediments from salt marsh [7,8], saline microbial mats and salt lakes [21], saline ponds [22], the Red Sea [17], the Great Salt Lake [2], and Sambhar Lake [6] have been investigated to select electroactive bacterial biofilms. In the majority of these studies, a positive correlation between salinity and current generation has been demonstrated.…”

“…However, all these studies were carried out at temperatures lower than or equal to 37°C and so none of this work examined the combined effect of increased salinity and high temperature on the bioanode current production, yet the salinity and thermal tolerance of halothermophilic microorganisms would make it possible to consider the design of halothermotolerant bioanodes that would be truly suitable for the treatment of hot, highly saline wastewater. In addition, the approaches used to improve the performance of bioanodes under saline or thermal conditions have so far been carried out by monitoring the influence of a single factor at a time, by following a single experimental response, which is often only the generation of current [3,6,7,8,15,21,22].These approaches, known as one-variable-at-a-time optimization, do not include the interactive effects between the variables studied. Consequently, this optimization does not depict the effects of all the factors on the response.…”

Osmotic Pressure Compensated Solute Ectoine Improves Salt Tolerance of Microbial Cells in Microbial Fuel Cells

“…The high concentrations of anions and cations in the MFCs substrate under high salt conditions can accelerate the ion migration rate, which can significantly reduce the internal resistance of MFCs which, in turn, is beneficial to MFCs electricity production. However, high salt environments also inhibit the growth of microbes . In this paper, we investigated the effects of different salt concentrations on the growth and electricity production of microbial flora in MFCs anodes.…”

“…Thus, the internal resistance of MFCs can be significantly reduced, which is beneficial to the electricity production . However, the high salt environment will also adversely affect the metabolism and growth of electrogenic microorganisms on the anode of MFCs, thereby affecting the population and community structure of anode biofilm, and may inhibit the electricity production and pollutants removal capacity of MFCs . Therefore, the problem of inhibition of microbial growth and metabolism under high salt conditions needs to be solved to obtain a high electricity generation of MFCs.…”