Microbial electrochemical systems for enhanced degradation of glyphosate: Electrochemical performance, degradation efficiency, and analysis of the anodic microbial community

Abstract

Glyphosate, one of the most used herbicides worldwide, is known as an aquatic contaminant of concern and can present adverse impacts in the agroecosystems. In this study, we investigated the degradation of glyphosate in microbial electrochemical systems (MESs), analysed the microbial composition of enriched anodic biofilms, and compared them with microbial communities of non-MESs enriched cultures. MESs supported higher glyphosate degradation (68.41 % to 73.90 %) compared to non-MESs cultures (48.88 %). The Linear Sweep Voltammetry (LSV) analysis showed that MESs operated at +300 mV, produced a maximum current of 0.611 mA, which was the highest among all the applied voltages. 16S amplicon sequencing revealed a significant difference in microbial community composition of MESs anodic biofilms and non-MESs enriched communities. The anodic biofilms were dominated by Rhodococcus (51.26 %), Pseudomonas (10.77 %), and Geobacter (8.67 %) while in non-MESs cultures, methanogens including Methanobrevibacter (51.18 %), and Methanobacterium (10.32 %), were the dominant genera. The present study suggested that MESs could be considered as a promising system for glyphosate degradation.