Nitrite accumulation during the denitration process with SBR treating pre-treated by anoxic/anaerobic up-flow anaerobic sludge bed (UASB) was observed at low temperatures. The effects of types of carbon sources on nitrite accumulation were investigated for comprehensive understanding the mechanism of nitrite accumulation. Experimental results clearly showed that nitrite accumulated obviously when five carbon sources (methanol, ethanol, sodium acetate, sodium propinoate and glucose), except for glucose, were used as electron donor. Additionally, nitrite accumulations were observed at four different initial nitrate concentrations and lower temperatures. The maximum concentrations of nitrite accumulation were 37.8, 21.5, 25.2 and 18.8 mg/L, respectively, and the corresponding nitrite accumulation rates (N/VSS x t) were 0.117, 0.136, 0.235 and 0.068 g/(g x d) during the nitrite accumulation period. Two break points of "nitrate knee" and "nitrite knee" on oxidation reduction potential (ORP) profile indicated that the reduction reactions of nitrate and nitrite were completed, respectively.
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Water Res
January 2025
National Engineering Laboratory for Advanced Municipal Wastewater Treatment and Reuse Technology, Engineering Research Center of Beijing, Beijing University of Technology, Beijing 100124, PR China. Electronic address:
Hydroxylamine (HA) dosing is an effective strategy for promoting partial nitrification (PN); however, its impact on endogenous denitrification remains underexplored. In this study, long-term continuous HA dosing (1.4 mg/L) was introduced for over 110 days in a pilot-scale anaerobic/aerobic/anoxic (AOA) system treating municipal wastewater (66.
View Article and Find Full Text PDFPlants (Basel)
December 2024
College of Agronomy and Biotechnology, Yunnan Agricultural University (YNAU), Kunming 650201, China.
Quinoa () is an Andean allotetraploid pseudocereal crop with higher protein content and balanced amino acid composition in the seeds. Ammonium (NH), a direct source of organic nitrogen assimilation, mainly transported by specific transmembrane ammonium transporters (), plays important roles in the development, yield, and quality of crops. Many and their functions have been identified in major crops; however, no systematic analyses of and their regulatory networks, which is important to increase the yield and protein accumulation in the seeds of quinoa, have been performed to date.
View Article and Find Full Text PDFMicroorganisms
December 2024
School of Environmental Science and Engineering, Sun Yat-Sen University, Guangzhou 510006, China.
A novel bacterial strain, DGFC5, was isolated from a municipal sewage disposal system. It efficiently removed ammonium, nitrate, and nitrite under conditions of 5% salinity, without intermediate accumulation. Provided with a mixed nitrogen source, DGFC5 showed a higher utilization priority for NH-N.
View Article and Find Full Text PDFMicroorganisms
November 2024
State Key Laboratory of Biocatalysis and Enzyme Engineering, Environmental Microbial Technology Center of Hubei Province, College of Life Sciences, Hubei University, Wuhan 430062, China.
Poly-γ-glutamic acid (γ-PGA) is a natural polymer whose molecular weight and viscosity are critical for its application in various fields. However, research on super-high-molecular-weight or -viscosity γ-PGA is limited. In this study, the gene in WX-02 was knocked out using homologous recombination, and the batch fermentation performances of the recombinant strain WX-ΔpgdS were compared to those of WX-02.
View Article and Find Full Text PDFFoods
December 2024
School of Food Science and Engineering, South China University of Technology, Guangzhou 510640, China.
This study investigated the effect of fermentation-promoting peptides (FPPs) on the improvement of the quality of cowpea pickles during fermentation and storage. FPPs were introduced to evaluate their effects on key parameters such as pH, total acidity, nitrite levels, and salinity. FPP accelerated fermentation by stimulating lactic acid bacteria (LAB) activity, leading to a rapid reduction in pH and a stable increase in total acidity.
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