The degradation of glyphosate is enhanced in a microbial fuel cell: Electrochemical performance, degradation efficiency, and analysis of the anodic microbial community

Glyphosate, one of the most used herbicides worldwide, is known as an aquatic contaminant of concern, and has been identified as presenting adverse impacts in agroecosystems, due to a somewhat limited natural chemical and biological degradation in the environment. In this study, we investigated the degradation of glyphosate in microbial electrochemical systems (MESs), and compared the performance and the microbial composition of enriched anodic biofilms with those shown by native microbial communities. The reduction of glyphosate content observed in MESs (approx. 70 %) was much higher than in non-electroactive microbial cultures (approx. 49 %). The analysis of the microbial communities by 16S amplicon sequencing revealed a significant difference between the microbial community composition of MESs anodic biofilms and non-electroactive 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 complete degradation of glyphosate from waters polluted by this herbicide.