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The rapid enrichment of anaerobic ammonia oxidation (anammox) bacteria (AnAOB) is challenging owing to their slow growth rate. Substrate supply strategies influence the AnAOB yield and anammox performance. In this study, a feeding strategy for low nitrogen strength with constant substrate concentrations and a hydraulic retention time decreasing over a gradient was investigated in an up-flow sludge blanket reactor. With increasing nitrogen load, the nitrogen removal rate increased from 0.2 to 6.3 kg-N m day, and the ratios among ammonium utilization, nitrite depletion, and nitrate production changed from 1:2.62:2.03 to 1:0.99:0.17. Excessive extracellular adenosine triphosphate (ATP) release occurred under famine conditions, whereas intracellular ATP accumulated under feast conditions. Rapid AnAOB growth, with a doubling time of 2 d, was associated with high microbial viability. A combined strategy of low nitrogen strength and microbial viability was proposed for the rapid growth of AnAOB. These results demonstrate accelerated process start-up and help us to understand anammox metabolism in depth.
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http://dx.doi.org/10.1016/j.biortech.2025.132403 | DOI Listing |
Ecotoxicol Environ Saf
September 2025
Instititue of International Rivers and Eco-security, Yunnan Key Laboratory of Eco-security, Yunnan University, Kunming 650091, China.
Freshwater lakes are increasingly subject to simultaneous nutrient enrichment and antibiotic pollution, yet the joint effects of these stressors on microbial network structure remain poorly characterized. This study examined the combined effects of nutrients and antibiotics on bacterial communities across eight bays in Erhai Lake, which were classified into high-, moderate-, and low-pollution zones. High-pollution bays (Haichao, Dongsha, and Shuanglang) recorded the region's highest nutrient concentrations, with chemical oxygen demand reaching 33.
View Article and Find Full Text PDFJ Environ Manage
September 2025
National Engineering Research Center for Efficient Utilization of Soil and Fertilizer Resources, College of Resources and the Environment, Shandong Agricultural University, Tai'an, 271018, China.
Excessive use of conventional potassium chloride (KCl) fertilizer has led to soil degradation problems such as compaction and salinization. While controlled-release potassium chloride (CRK) fertilizer has the potential to enhance crop productivity and mitigate these problems, its impact on soil quality (SQ) remains unclear. In this study, four potassium (K) fertilization treatments were established: no K application (CK), conventional KCl fertilizer (CRK0), 50 % substitution with CRK (CRK0.
View Article and Find Full Text PDFJ Phys Chem A
September 2025
National Synchrotron Radiation Laboratory, University of Science and Technology of China, Hefei 230026, China.
To elucidate possible mechanisms of nitrogen chemistry between ammonia (NH) and ethanol, the potential pathways of ethanol radicals (Wa, Wb, and Wc) following H-abstraction by NH radicals were primarily investigated including HCN addition, H-transfer, and dissociation reactions by quantum chemical calculations. The rate constants were solved in the master equation based on RRKM and TST theory and fitted to the Arrhenius equation. The results demonstrate that H-abstraction from CHOH by NH at the b-site is the most competitive, facilitating subsequent HCN addition.
View Article and Find Full Text PDFProg Nucl Magn Reson Spectrosc
February 2025
Brown Boveri Platz 4, 5400 Baden, Switzerland.
Zero and ultralow-field nuclear magnetic resonance (ZULF NMR) is an NMR modality where experiments are performed in fields at which spin-spin interactions within molecules and materials are stronger than Zeeman interactions. This typically occurs at external fields of microtesla strength or below, considerably smaller than Earth's field. In ZULF NMR, the measurement of spin-spin couplings and spin relaxation rates provides a nondestructive means for identifying chemicals and chemical fragments, and for conducting sample or process analyses.
View Article and Find Full Text PDFEnviron Res
September 2025
Yunnan Key Laboratory for Plateau Mountain Ecology and Restoration of Degraded Environments & School of Ecology and Environmental Sciences, Yunnan University, Kunming, 650500, China; Central Yunnan Field Scientific Station for Restoration of Ecological Function & Yunnan International Joint Research
The expansion of floriculture has increased the need for sustainable floral waste management to support agricultural carbon neutrality. This study assessed the impact of carnation, lily, and rose straw amendments (with varying C/N ratios, lignin, and cellulose) on GHG emissions and soil quality with earthworm (Eisenia fetida). Controlled microcosm experiments were conducted to examine the effects of straw types and earthworms on CO and NO fluxes, as well as soil properties, enzyme activities, and microbial functions.
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