Electrical performance and application in sewage treatment of an electricigenic strain Stenotrophomonas acidaminiphila EFS1

Abstract:

[Background] As a new type of fuel cell resource, microbial fuel cell (MFC) can be used in sewage treatment field to maximize resources while generating electricity. [Objective] A culturable microorganism isolated from MFC was used to study its electrical performance and to characterize the flocculation ability, heavy metal tolerance and the possibility of phenol degradation in sewage treatment of Stenotrophomonas sp. which provides a theoretical basis for expanding the resources pool of electricigens. [Methods] An electrogenic bacterial strain named EFS1was isolated from the anode of MFC using a WO3 nano-probe. The anode electrode was observed by cyclic voltammetry combined with scanning electron microscope, and the polarization curve and power density curve were measured by changing the external resistance. Finally, the flocculation, heavy metal tolerance and phenol degradation of the strain were determined. [Results] The strain was identified as Stenotrophomonas acidaminiphila through the evidences of 16S rRNA, morphology, physiology and biochemistry. The strain EFS1 had a stable cycle of electricity production, the maximum periodic voltage was 300 mV, and the power density was up to 56.25 mW/m2, scanning electron microscopy found that the strain had direct contact with electrodes and secreted electron mediators to transfer electrons; the internal resistance of MFC was about 1 000 Ω. The flocculation rate of the strain could reach 70% under aerobic conditions and 80% in an anaerobic environment with electron acceptor. The strain also had good tolerance to Cd2+, Cu2+, Mn2+ and phenol degradation performance, in which the phenol degradation rate reached 100% at 48 h and 2–4 mg/L. [Conclusion] This study verified that the electrogenic bacteria strain EFS1 had flocculation ability, heavy metal tolerance, and the possibility of phenol degradation and provide theoretical base for the development of electricity producing bacteria and sewage treatment.