Isolation and characterization of a salt-tolerant exoelectrogenic strain Shewanella algae E-1

Abstract:

[Background] The types and electrochemical activity mechanism of exoelectrogenic microorganisms have important influence on the electrogenic performance of microbial fuel cells. [Objective] A salt-tolerant exoelectrogenic strain was isolated from seawater, its exoelectrogenic characteristic was studied and the species information was identified. [Methods] A pure exoelectrogenic bacterium (designated as E-1) was isolated from the enriched anodic biofilm of microbial fuel cells (MFCs), where the seawater from the south sea in China was used as the inoculum and MFCs were operated in the anolytes without and with salt addition. The exoelectrogenic characteristic of the pure isolate strain E-1 was investigated by inoculating into MFCs containing different salt concentrations. The species information was identified using the combined methods of morphological observation, Biolog analysis and 16S rRNA gene sequence alignment. [Results] The power densities of strain E-1 were respectively 51.69 mW/m2 and 26.56 mW/m2 without salt addition and with addition of 6.6% NaCl, which was related to its good salt tolerance. The strain E-1 was identified as Shewanella algae, which showed diversity in substrate utilization, and its growth temperature and pH range were 25?40 °C and 5.0?10.0, respectively. [Conclusion] The strain affiliated to S. algae is firstly reported to show electricity activity when applying in MFCs, which enriches the diversity of electricigens. S. algae E-1 can generate electricity at high salt concentration, which provides a new experimental material for the application of MFCs in seawater resourceful treatment.