Dual character of methane production and antibiotic resistance genes reduction by adding nano-Fe2O3 during anaerobic digestion of swine manure

Nano-Fe2O3 are widely used in products, which were washed into the sewage system. In this study, effects of nano-Fe2O3 addition on methane production and antibiotic resistance genes (ARGs) reduction were investigated during anaerobic digestion (AD) of swine manure. The fate of ARGs were performed through the high-throughput qPCR (HT-qPCR), and key functional genes and microbial community were evaluated by adding nano-Fe2O3.The reactive oxygen species (ROS) can accelerate death of the host of ARGs associated with mainly ARGs reduction by a maximum of 33.4%. Nano-Fe2O3 could improve the methane production before day12 and inhibition impacts in this study were emerged after the 13th day of BMP test. The exposure of nano-Fe2O3 with short time is beneficial for the methanogenic activity to improve methane production by direct interspecies electron transfer (DIET) mechanism in AD. But the high dosage of nano-Fe2O3 completely is disrupted the cell integrity and damages the bacterial community led to the lowest methane production because of the strong dispersion of nano-Fe2O3 during the AD.