Ammonia assimilation: A double-edged sword influencing denitrification of Rhodobacter azotoformans and for nitrogen removal of aquaculture wastewater. (February 2022)

• Record Type: Journal Article
• Authors: Li, Zhen; Li, Lu; Sun, Haoyu; Wang, Wenjuan; Yang, Yuying; Qi, Zhengliang; Liu, Xinli
• Is Part Of: Bioresource technology. Volume 345(2022)
• Publication Date: 2022-02
• Subjects: R. azotoformans -- Ammonia assimilation -- Denitrification -- Nitrogen removal -- Aquaculture wastewater; Biomass -- Periodicals; Biomass energy -- Periodicals; Bioremediation -- Periodicals; Agricultural wastes -- Periodicals; Factory and trade waste -- Periodicals; Organic wastes -- Periodicals; Bioénergie -- Périodiques; Déchets agricoles -- Périodiques; Déchets industriels -- Périodiques; Déchets organiques -- Périodiques; Déchets (Combustible) -- Périodiques; 662.88
• DOI: 10.1016/j.biortech.2021.126495
• Languages: English
• ISSNs: 0960-8524

Abstract

Graphical abstract: Highlights: Low NH4 + -N concentrations accelerates denitrification while high concentrations are inhibitory. NH4 + -N concentration > 0.3 mM inhibits NO reduction causing denitrification depression. Denitrification efficiency is improved via optimizing initial NH4 + -N concentrations. Abstract: NO3 − -N and NH4 + -N are two prevalent nitrogenous pollutants in aquaculture wastewater posing a significant health risk to aquatic animals. R. azotoformans ATCC17025 can rapidly denitrify to remove NO3 − -N, assimilating NH4 + -N. The study investigated the influence of ammonia assimilation on bacterial denitrification. Results revealed that low concentration of NH4 + -N (≤0.3 mM) accelerated denitrification, whereas high concentration inhibited it. RT-qPCR indicated that the inhibition of NO reduction under high concentration of NH4 + -N was the primary cause of denitrification depression, whereas low concentration of NH4 + -N enhanced the synthesis of practically all enzymes involved in denitrification. Finally, nitrogen-rich aquaculture effluent was effectively treated in lab-scale using a semi-continuous operation that provided an appropriate NH4 + -N concentration for denitrification. This semi-continuous operation treated wastewater 2 times faster than the batch operation and the content of nitrogen decreased to effluent standard. The study can provide guidance for nitrogen removal of aquaculture wastewater with bioaugmentation.