Effect of Electrical Stimulation of the External Circuit of Membraneless Bioelectrochemical Systems on Imidacloprid Degradation and Representation of the mtrB and DyP-Type Peroxidases Genes

Abstract

In all variants where carbon felt was present, imidacloprid degradation by the microflora of bottom sediments was many times higher than in the control, reaching 84.0 ± 1.7% under the polar connection of an external voltage source (1.2 V). When Shewanella oneidensis MR-1 was introduced, almost complete degradation of the pollutant was observed, while in the control without electrodes, it was 29.7 ± 6.0%. The relative representation of the genes of the MtrB transmembrane protein of the respiratory chain, which is associated with exoelectrogenesis, depended on the external chain and had a maximum value when the voltage source was connected polarly, correlating with the pesticide degradation by the autochthonous microflora, similar to the DyP-type peroxidase genes. The introduction of S. oneidensis MR-1 resulted in an almost tenfold increase in the relative representation of DyP-type peroxidase genes. In all experimental variants, the values of the DyP relative representation were significantly higher than in the control without carbon felt, as well as the degree of imidacloprid degradation under these experimental conditions.