Sustainable and highly selective microbial ammonia synthesis from nitrate induced by electron flow

The data of DNA and RNA sequencing are from Illumina HiSeq 4000 (Illumina, San Diego, CA, USA) at Guangdong Magigene Technology Co., Ltd. Metagenome-assembled genomes (MAGs) were retrieved by MetaWRAP using the clean data obtained from metagenomic sequencing. The content of NADH and ratio of NADH/NAD+ were measured using a kit (NADH/NAD+ Assay Kit with WST-8, Beyotime Biotechnology). The viability of complex I, III, and Ⅳ was measured using a kit (mitochondrial respiratory chain complex I/III/IV test kit, Solarbio Science & Technology). The concentration of NH4+-N, NO3--N and NO2--N in water from the reactor were determined using a flow analyzer (SKALA, The Netherlands) after being filtered through a 0.45 μm membrane. The protein content in EPS was measured using the colorimetric method and the Bradford assay. Data were processed using Origin 9.0 (OriginLab, Northampton, MA, USA) and presented as mean ± standard deviation. All charts and plots were prepared using Origin.