Efficient degradation of carbamazepine and metagenomic investigations of anodic biofilm in microbial fuel cells.

Environmental contamination with carbamazepine is a considerable global problem. In this study, two-compartment microbial fuel cells (MFCs) were constructed to investigate the degradation performance of carbamazepine, and the degradation mechanism was further explored by using metagenomic analysis. The results showed that MFCs exhibited excellent carbamazepine removal performance and also generated electricity. The removal rate of carbamazepine reached 73.56% over the 72-h operation period, which was 3.09 times higher than that of the traditional anaerobic method, and the peak voltage of the MFCs could reach 416 mV. Metagenomics revealed significant differences in microbial community composition between MFCs and the traditional anaerobic method (p < 0.05), and Proteobacteria (81.57%) was predominant bacterial phyla during the degradation of carbamazepine by MFCs. Among them, the microbial communities at the genus level were mainly composed of Pseudomonas, Pusillimonas, Burkholderia, Stenotrophomonas, Methyloversatilis and Nitrospirillum. Kyoto Encyclopedia of genes and genomes (KEGG) metabolic pathway analysis showed that the number of genes related to carbon and nitrogen metabolism increased by 85.12% and 142.25%, respectively. Importantly, a greater number of genes of microbial grown on the surface of anode were assigned to denitrification and the degradation of aromatic compounds. This research provides a cost-effective method for treating wastewater contaminated with carbamazepin.