• Membrane and Water Treatment
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• v.11 no.5
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• pp.345-351
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• 2020

Eutrophication of surface waters is commonly caused by excessive inputs of nutrients such as nitrogen and phosphorus. Nakdong River basin was chosen as the study area to investigate the effect of point and non-point source pollution of nitrogen on eutrophication in water body. Non-point source inputs of nitrogen accounted for approximately 84% in the total nitrogen input of the upper Nakdong river watershed, which mainly consists of agricultural land and forests. However, point source inputs of nitrogen accounted for 58~85% in the total nitrogen input of the middle and lower watersheds, including urban area. Therefore, for watershed near urban area, control of point source inputs of nitrogen may be an optimal method to control eutrophication. In this respect, the enforcing reduction of nitrogen in the final effluent of wastewater treatment facilities is needed. On the other hand, to enact more stringent nitrogen regulations, the LOT (limit of technology) and environmental impact should be considered. In this study nitrogen data were analyzed to propose new nitrogen regulations.

• Journal of Environmental Health Sciences
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• v.28 no.5
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• pp.1-3
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• 2002

This study was to evaluate on the removal efficiencies of total nitrogen and phosphorus in municipal wastewater at MUNR process using sludge carbon source for environmental micro-organism. The removal efficiencies of total suspended solid were 85.9~91％, total nitrogen were 38.6~87.2％ and total phosphorus were 30.8~39.0％, respectively. It was shown that removal efficiency of nitrogen was effectively influenced by sludge carbon source treated with ultrasonication. The removal efficiency of total phosphorus was low because the sludge was not wasted during this treatment.

• Journal of Environmental Health Sciences
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• v.28 no.1
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• pp.93-97
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• 2002

The aim of this study was to evaluate on the removal effect of total nitrogen and phosphorus with municipal wastewater in ultrasonic nutrient removal (UNR) process using ultrasonic sludge carbon source. The removal efficiency for total nitrogen was 44.2% at biological nutrient removal (BNR) process, 50.8% at UNR process. The removal efficiency for total phosphorus was 45.6% at BNR process, 46.2% at UNR process. The removal of nitrogen was effectively influenced by ultrasonic sludge carbon source.

• The Korean Journal of Mycology
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• v.41 no.3
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• pp.149-159
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• 2013

The nitrogen source-requirement and preference of ectomycorrhizal fungi (42 strains belong to 13 genera) collected from Korean forests were investigated by incubating mycelial cells in four nitrogen source test media for 56 days. The nitrogen requirement was relatively high in five strains (Heimioporus japonicas (KFRI 1224), Suillus luteus (KFRI 1232), Tylopilus castaneiceps (KFRI 1383), Suillus granulates (KFRI 1997), Rhizopogon sp. (KFRI 1434)) in comparison with other strains. Forty-five percent of ectomycorrhizal strains including Boletus griseus (KFRI 1362) preferred the ammonium-form of inorganic nitrogen source for mycelial growth, whereas thirty-six percent of tested strains including Suillus grevillei (KFRI 1125) preferred the nitrate-form as an inorganic nitrogen source.

• Journal of Microbiology and Biotechnology
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• v.12 no.6
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• pp.979-985
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• 2002

The possibility of microalgal nitrogen treatment was tested in wastewaters with a low carbon/nitrogen (C/N) ratio. Chlorella kessleri was cultured in the two different artificial wastewaters with nitrate as a nitrogen source: one contained glucose for an organic carbon source and the other without organic carbon sources. The growth rates of the two cultures were almost identical when the aeration rate was over 1 vvm. These results suggest that microalgae could successfully remove nitrogen from wastewater, as far as the mass transfer of $CO_2$, was not limited. Nitrate was successfully reduced to below 2 mg $NO_3^-$-N/ml from the initial nitrate concentration of 140 mg $NO_3^-$-N/ml in 10 days, even in the wastewater with no organic carbon source. Similar results were obtained when ammonium was used as the sole nitrogen source instead of nitrate. Higher concentrations of nitrogen of 140, 280, 560 and 1,400 mg/ml were also tested and similar amounts of nitrogen were removed by algal cultures without showing any substrate inhibition.

• Journal of the Korean Wood Science and Technology
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• v.38 no.2
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• pp.124-134
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• 2010

This study was performed to evaluate the efficiency of using softwood as the sawdust medium for Lentinula edodes cultivation, effect of nutrient on the mycelial growth, spawning, the mushroom yield, and quality. The nitrogen nutrition significantly enhanced the mycelial growth of L. edodes. The glutamic acid in the L. leptolepis and P. koraiensis, and asparagine in the P. densiflora were appeared to slight increase in the mycelial growth. The vegetable oil showed very effective on the mycelial growth in the P. koraiensis sawdust medium. Carbon/nitrogen ratio of all the test was reduced after mycelial growth. The mycelial growth was exclusively dependent on reduction of carbon. The mushroom yield (32.7%) of the P. densiflora sawdust medium (carbon source: 3% active carbon, nitrogen source: 0.4% asparagines) was the best in mushroom production of L. edodes, followed by the Q. variabilis sawdust (35.4%) of the control medium. The diameter of mushroom cap was obtained from the P. densiflora sawdust (carbon source: 3% sucrose, nitrogen source: 0.4% potassium nitrate) and P. koraiensis sawdust (carbon source: 3% sucrose, nitrogen source: 0.4% potassium nitrate), and the P. koraiensis sawdust (carbon source: 3% xylose, nitrogen source: 0.4% glutamic acid, supplement: 0.05% amino acid), with values 71.5 mm, 71.5 mm and 72.1 mm, respectively. In the polypropylene bag cultivation, the weight losses of the block medium gradually increased for 80 days in the dark (13.8~16.8%) and then became stable in the range of 20.7~25.8%.

• KSBB Journal
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• v.11 no.4
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• pp.497-503
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• 1996

In this study, the effects of nitrogen sources and pH on pullulan production were investigated. As a result, the best nitrogen source in pullulan production by Aureobasidium pullulans was shown to be peptone and its product yield was 62%. Optimum concentration of carbon/nitrogen source ratio was 50/0.15 and the production of pullulan was inhibited at ratios higher than 50/0.15. Aureobasidium pullulans had produced 29.1, 27.4 and 26.5 g/L pullulan, respectively in media I, II, and III containing mixed nitrogen sources. This result showed that pullulan could be produced efficiently from mixed nitrogen source. It was found that pullulan yield with pH control was higher than that with no pH control. In fedbatch fermentation, pullulan yield obtained with a feeding rate of 0.05 N-g/L for nitrogen source was higher than that without nitrogen source feeding.

• Proceedings of the Korean Society of Soil and Groundwater Environment Conference
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• 2003.09a
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• pp.279-281
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• 2003

This study is intended to give information on agricultural nonpoint source pollution and transport related to fertilizer application and irrigation practice. Field-simulated soil columns were set up and leaching studies on fertilizer components such as nitrogen and phosphorus were performed. Nitrogen and phosphorus in the leachate showed different trends in each column and nonpoint source pollution in agricultural areas may be expected to depend on planted crops, soil conditions, and climate as well as irrigation and fertilizing management.

• Microbiology and Biotechnology Letters
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• v.1 no.1
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• pp.3-11
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• 1973

The biochemical characteristics of Astradix -P, isolated from Astragalus membranaceus Bunge as yeaststatic substance, were reported on a previous paper. And on this report, some relation to the nitrogen metabolism of yeast was studied. Inorganic or organic source of nitrogen easily uptaking yeast did not show any antagonistic action to the inhibitory action of Astradix -P on the yeast growth. Especially an organic nitrogen source, arginine, histidine and lysine, classified to basic amino acid, was reacted as an antagonistic substance to the sample. But, ornithine, a basic amino acid, did not show any antagonistic action to the sample. In the mixed media containing neutral and acidic amino acids as a nitrogen source, yeast growth was inhibited strongly. If the basic amino acid was added to the same mixed media, the yeast growth was not inhibited by Astradix-P therefore, the antagonistic action of basic amino acid to the Astradix-p was readily observed. The yeast static action of Astradix-P was partially related to the isoelectric point of amino acid as a nitrogen source. Yeast cells which propagated under the media containing growth inhibitor, Astradix -p, did not bring any remarkable denaturation of cell structure by electro-microscopic observation.

• KSBB Journal
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• v.6 no.4
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• pp.369-377
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• 1991

The effects of nitrogen sources(sodium glutamate and peptone) on the production of xanthan gum were investigated. The fermentation using sodium glutamate as a nitrogen source is longer than that of peptone. In the initial nitrogen concentration of 0.4-1.0g/L, Bs was about 2.0 and ${\beta}$s was 1.2. The optimal yields were obtained when the carbon source/nitrogen concentration was 10-16. The fermentation time and product yields in the fermentation medium of mixed nitrogen source [sodium glutamate-N(0.75g/L)+peptone-N(0.25g/L)] were similar to those of peptone.