Kinetics and gene diversity of denitrifying biocathode in biological electrochemical systems

Abstract

Cathodic denitrification using a bioelectrochemical system removes nitrogen at a low C/N ratio, and also harvests energy as electricity. Denitrifying biocathodes were cultured using three electrode systems with .A high-throughput sequencing analysis of 16S rRNA gene showed high biodiversity in a denitrifying biocathode and nitrite contributed more to the formation of cathodic microbial community structure. Denitrification functional gene analysis revealed Pseudomonas are effective denitrifiers in a biocathode.

Integrated experimental and modeling evaluation of removal efficiency and energy consumption for an autotrophic denitrifying biocathode

“…27 The maximum NO 3 − removal rate, r Na max (1.8 mgN gVSS −1 h −1 ) was higher than the maximum NO 2 − removal rate r Ni max (0.96 mgN gVSS −1 h −1 ); this is consistent with previous reports of higher NO 3 − removal kinetics than NO 2 − in biocathodic denitrification systems. 39 Although the values reported in our model are higher than those reported in Srinivasan et al 22 (1.68 and 0.45 mgN gVSS −1 h −1 respectively), this behavior can be explained by the fact that the poised biocathodes usually have higher denitrifying performances compared to biocathodes in MFCs. Anodic organic matter oxidation in MFC often generated electron limitations at the biocathode.…”

Challenges and applications of nitrate-reducing microbial biocathodes

“…Indeed, in the great majority of studies about NRB, different carbon materials are used as electrode, for example carbon paper [93,114,115,133,135], carbon cloth [134,137,143,145,150,151], graphite felt [84,112,155,116,118,119,122,146,[152][153][154], carbon felt [68,117,130,[156][157][158][159][160][161], graphite rods, bars and plates [70,107,113,131,138,162,163],…”

Progress in Nitrogen Removal in Bioelectrochemical Systems

“…Denitrifiers were the most abundant bacteria in the cathode biofilm, comprised of Comamonas, Paracoccus, Dechloromonas, Thermomonas, Rubrivivax, Simplicispira, Thiobacillus, and Geobacter responsible for alleviating nitrate accumulation. Additionally, the source of nitrogen was revealed to affect the microbial structure [39,67]. It was observed that NO 2 − , relative to NO 3 − , was the main screening for the microbial community of nitrogen removal biocathode [39].…”

“…Additionally, the source of nitrogen was revealed to affect the microbial structure [39,67]. It was observed that NO 2 − , relative to NO 3 − , was the main screening for the microbial community of nitrogen removal biocathode [39]. Proteobacteria was the shared dominant phylum (40%) in biofilms fed with NO 3 − , NO 2 − , or a mixture of NO 3 − and NO 2 − .…”