The inhibition of free ammonia (FA) on nitrite-oxidizing bacteria (NOB) was investigated using an enriched NOB community with high nitrifying performance. A continuous-flow reactor was operated for the enrichment of the bacterial community. High-throughput sequencing analysis showed that (NOB) using in batch experiments was extended from 4.78% to 12.08% during the under continuous-flow operation for 27 days. For each batch experiments, an ammonia injection at the start-up resulted in the desired initial FA concentration (at pH = 8.1-8.2, = 25 °C), and a continuous ammonia feeding stream allowed for a relatively stabilized FA levels as much as the initial one. Results indicated that FA inhibition on NOB was not instantaneous but occurred gradually at a certain reaction time. Low concentrations of FA (18.08-24.95 mg L) had a limited inhibition on NOB with increasingly high nitrate production rates, whereas high FA levels (36.06-50.66 mg L) exerted a significant negative impact on the NOB. Also, strong adaptation happened in these high levels of FA inhibition on NOB, which resulted in an overall low NOB activity during the whole aerobic operation.
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http://dx.doi.org/10.1039/c8ra06198j | DOI Listing |
Carbohydr Polym
March 2025
College of Food Science and Engineering, Nanjing University of Finance and Economics/Collaborative Innovation Center for Modern Grain Circulation and Safety, Nanjing 210023, China. Electronic address:
Nobiletin (NOB), a lipid-soluble polymethoxyflavone with potent antioxidant, antimicrobial, and anti-inflammatory properties, suffers from poor stability and pH sensitivity, limiting its bioavailability. In this study, Pickering high internal phase emulsions (HIPEs) stabilized by soy protein isolate (SPI) and κ-carrageenan (KC) were developed to encapsulate and protect NOB. The emulsions, containing a 75 % medium-chain triglyceride (MCT) volume fraction, were optimized by investigating the effects of pH and KC concentration on the key properties such as the creaming index, particle size, zeta potential, microstructure, and rheology.
View Article and Find Full Text PDFFront Cell Dev Biol
December 2024
Key Laboratory of Agricultural Biosafety and Green Production of Upper Yangtze River (Ministry of Education), College of Horticulture and Landscape Architecture, Southwest University, Chongqing, China.
Plant-driven extracellular vesicles (PEVs) have attracted significant interest due to their natural origin, remarkable bioactivity, and efficacy in drug encapsulation and target delivery. In our work, extracellular vesicles from Citri Reticulate Pericranium (CEVs) were isolated and investigated their physicochemical characteristics and biological activities. We identified the vesicle structures as regular, with a particle size of approximately 200 nm.
View Article and Find Full Text PDFEnviron Res
January 2025
Key Laboratory of Water Science and Water Environment Recovery Engineering, Beijing University of Technology, Beijing, 100123, China; State Key Laboratory of Urban Water Resource and Environment, Harbin Institute of Technology, Harbin, 150090, China.
Stable inhibition of nitrite-oxidizing bacteria (NOB) is a significant challenge in achieving partial nitrification (PN) and partial nitrification-anaerobic ammonia oxidation (PNA). Growing evidence suggested that NOB can develop resistance to suppression over time, leading to the re-enrichment of NOB within reactors. To address these issues, this study aimed to achieve stable PN by regulating SRT to selectively washout NOB during the lag phase of activity recovery following FA/FNA exposure.
View Article and Find Full Text PDFJ Environ Manage
January 2025
Department of Environmental Science and Engineering, Zhejiang Ocean University, No.1 Haida South Road, Zhoushan, 316022, PR China; Zhejiang Provincial Key Laboratory of Petrochemical Environmental Pollution Control, Zhoushan, 316022, PR China. Electronic address:
In order to study the resistance mechanisms of biofilm and granular sludge to various dissolved oxygen (DO) exposures in anaerobic ammonium oxidation (anammox) process, a biofilm - granular sludge anammox reactor was established and operated. Experimental results showed that DO levels of ≤0.41 mg L hardly affected the total nitrogen removal efficiency (TNRE).
View Article and Find Full Text PDFWater Res
March 2025
State Key Joint Laboratory of Environment Simulation and Pollution Control, School of Environment, Tsinghua University, Beijing, China; Research and Application Centre for Membrane Technology, School of Environment, Tsinghua University, Beijing, 100084, China. Electronic address:
The integration of partial nitrification-anammox (PN/A) into membrane-aerated biofilm reactor (MABR) is a promisingly energy-efficient and high-efficiency technology for nitrogen removal. The inhibition of nitrite oxidizing bacteria (NOB) remains as the most significant challenge for its development. In our investigation, we proposed a novel process to integrate carriers to MABR (CMABR), which combined the carriers enriched with anaerobic ammonium-oxidizing bacteria (AnAOB) and partial nitrifying MABR system.
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