Metagenomic analysis of microbial community and gene function of anodic biofilm for nonylphenol removal in microbial fuel cells

Abstract

Nonylphenol as a high priority control of persistent toxic contaminant has been frequently detected in environment. In this study, Dual-chamber microbial fuel cells (MFCs) were constructed for simultaneous nonylphenol degradation and electricity generation; and microbial community and gene function of anodic biofilm were analyzed through metagenomic sequencing. The results showed that nonylphenol removal rate reached 82% within 60 h in MFCs, and the maximum voltage achieved 0.60 V when the external resistance was 1000 Ω. Metagenomics analysis showed that Proteobacteria and Actinobacteria were dominant phyla in biofilm attached to anode. At genus level, the relative abundance of Streptomyces (21.45%), Microbacterium (11.96%), Burkholderia (10.90%), Pusillimonas (7.59%), Stenotrophomonas (6.62%), Pseudomonas (4.44%), Nitrospirillum (3.75%), Nocardia (1.73%), Arthrobacter (1.71%) and Bacillus (1.21%) were remarkably higher than those of control groups. In terms of functional genes annotation, a relatively high gene number was focus on various metabolic pathways (such as carbon metabolism, riboflavin metabolism, and nitrogen metabolism) during MFCs operated. The metabolic pathways of nonylphenol were suggested to divide into the oxidation of aromatic ring (route-1) and the fission of alkyl chain (route-2) based on KEEG analysis.