UTILIZATION OF WEED MANURES AND BIOFERTILIZER AS A NUTRIENT SOURCE TO PHASEOLUS AUREUS ROXB

The aim of the study was to determine if solid, slightly soluble compounds can be used as nutrient source in activated sludge treatment plants instead of liquid phosphoric acid. Four different solid materials were tested in lab-scale solubility tests to find compounds which are least soluble. Two materials were chosen for further studies: apatite and raw phosphate. The use of apatite and raw phosphate as nutrient source was studied in lab-scale activated sludge reactors along with a control reactor where phosphorus was added in liquid form. The phosphorus dosage, measured as elementary phosphorus, was the same for all three reactors. The reactors were fed with pre-clarified chemi-thermomechanical pulp mill (CTMP) wastewater. There were no significant differences in the reductions of organic matter between the three reactors. The mean effluent concentration of total phosphorus was 3 mg P/l in the control reactor and less than 1 mg P/1 in the other two reactors. The soluble phosphorus concentration was more than 2 mg P/l in the control reactor and less than 0.5 mg P/l in the other two. Apatite was an even better nutrient source than raw phosphate. Further lab-scale tests were conducted using two different grain sizes of apatite. No significant differences were found between the studied grain sizes (<0.074 mm and 0.074 mm-0.125 mm). Apatite was then used in full-scale at a CTMP-mill two different times. The experiments showed that the mean concentrations of phosphorus can be reduced radically by using apatite as a nutrient source instead of liquid phosphorus. Solid phosphorus compounds are a viable alternative to reduce the phosphorus load from forest industry wastewater treatment plants.

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Effects of Soil, Cover Crop, and Nutrient Source on Amounts and Forms of Phosphorus Movement Under Simulated Rainfall Conditions

Journal of Environmental Quality ◽

10.2134/jeq1978.00472425000700010010x ◽

1978 ◽

Vol 7 (1) ◽

pp. 50-54 ◽

Cited By ~ 16

Author(s):

G. Y. Reddy ◽

E. O. Mc Lean ◽

G. D. Hoyt ◽

T. J. Logan

Keyword(s):

Cover Crop ◽

Soil Cover ◽

Simulated Rainfall ◽

Nutrient Source

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Mechanism of NanR gene repression and allosteric induction of bacterial sialic acid metabolism

Nature Communications ◽

10.1038/s41467-021-22253-6 ◽

2021 ◽

Vol 12 (1) ◽

Author(s):

Christopher R. Horne ◽

Hariprasad Venugopal ◽

Santosh Panjikar ◽

David M. Wood ◽

Amy Henrickson ◽

...

Keyword(s):

Sialic Acid ◽

Dna Binding ◽

Protein Interactions ◽

Acid Metabolism ◽

Environmental Changes ◽

Dna Interaction ◽

Protein Protein Interactions ◽

Nutrient Source ◽

Cryo Electron Microscopy ◽

Close Proximity

AbstractBacteria respond to environmental changes by inducing transcription of some genes and repressing others. Sialic acids, which coat human cell surfaces, are a nutrient source for pathogenic and commensal bacteria. The Escherichia coli GntR-type transcriptional repressor, NanR, regulates sialic acid metabolism, but the mechanism is unclear. Here, we demonstrate that three NanR dimers bind a (GGTATA)3-repeat operator cooperatively and with high affinity. Single-particle cryo-electron microscopy structures reveal the DNA-binding domain is reorganized to engage DNA, while three dimers assemble in close proximity across the (GGTATA)3-repeat operator. Such an interaction allows cooperative protein-protein interactions between NanR dimers via their N-terminal extensions. The effector, N-acetylneuraminate, binds NanR and attenuates the NanR-DNA interaction. The crystal structure of NanR in complex with N-acetylneuraminate reveals a domain rearrangement upon N-acetylneuraminate binding to lock NanR in a conformation that weakens DNA binding. Our data provide a molecular basis for the regulation of bacterial sialic acid metabolism.

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