• Clean Technology
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• v.4 no.2
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• pp.23-31
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• 1998

Photo-sensitized oxidation of benzene in aqueous solution was conducted with persulfate, nitrate, nitrite, sulfate and chloride as sensitizers.In the photo-sensitized oxidation of benzene persulfate, nitrate and nitrite could act as sensitizers, while no detectable effects could be observed with sulfate and chloride. With increasing nitrite concentration the photo-sensitized oxidation of benzene ran through a maximum value and decreased thereafter with increasing nitrite concentration. A build-up of nitrite ions seemed to scavenge hydroxyl radicals. When nitrite was present with other ions, nitrite inhibited the photo-sensitized oxidation of benzene. Phenol and biphenyl were identified as intermediate.

• Journal of Microbiology and Biotechnology
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• v.23 no.5
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• pp.719-723
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• 2013

Nitrification in wastewater treatment emits a significant amount of nitrous oxide ($N_2O$), which is one of the major greenhouse gases. However, the actual mechanism or metabolic pathway is still largely unknown. Selective nitrification inhibitors were used to determine the nitrification steps responsible for $N_2O$ emission with activated sludge and enriched nitrifiers. Allylthiourea (86 ${\mu}M$) completely inhibited ammonia oxidation and $N_2O$ emission both in activated sludge and enriched nitrifiers. Sodium azide (24 ${\mu}M$) selectively inhibited nitrite oxidation and it led to more $N_2O$ emission than the control experiment both in activated sludge and enriched nitrifiers. The inhibition tests showed that $N_2O$ emission was mainly related to the activity of ammonia oxidizers in aerobic condition, and the inhibition of ammonia monooxygenase completely blocked $N_2O$ emission. On the other hand, $N_2O$ emission increased significantly as the nitrogen flux from nitrite to nitrate was blocked by the selective inhibition of nitrite oxidation.

• Journal of Microbiology and Biotechnology
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• v.20 no.3
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• pp.485-493
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• 2010

A modified graphite felt electrode with neutral red (NR-electrode) was shown to catalyze the chemical oxidation of nitrite to nitrate under aerobic conditions. The electrochemically oxidized NR-electrode (EO-NR-electrode) and reduced NR-electrode (ER-NR-electrode) catalyzed the oxidation of $1,094{\pm}39$ mg/l and $382{\pm}45$ mg/l of nitrite, respectively, for 24 h. The electrically uncharged NR-electrode (EU-NR-electrode) catalyzed the oxidation of $345{\pm}47$ mg/l of nitrite for 24 h. The aerobic bacterial community immobilized in the EO-NR-electrode did not oxidize ammonium to nitrite; however, the aerobic bacterial community immobilized in the ER-NR-electrode bioelectrochemically oxidized $1,412{\pm}39$ mg/l of ammonium for 48 h. Meanwhile, the aerobic bacterial community immobilized on the EU-NR-electrode biochemically oxidized $449{\pm}22$ mg/l of ammonium for 48 h. In the continuous culture system, the aerobic bacterial community immobilized on the ER-NR-electrode bioelectrochemically oxidized a minimal $1,337{\pm}38$ mg/l to a maximal $1,480{\pm}38$ mg/l of ammonium to nitrate, and the community immobilized on the EU-NR-electrode biochemically oxidized a minimal $327{\pm}23$ mg/l to a maximal $412{\pm}26$ mg/l of ammonium to nitrate every two days. The bacterial communities cultivated in the ER-NR-electrode and EU-NR-electrode in the continuous culture system were analyzed by TGGE on the $20^{th}$ and $50^{th}$ days of incubation. Some ammonium-oxidizing bacteria were enriched on the ER-NR-electrode, but not on the EU-NR-electrode.

• Journal of Microbiology and Biotechnology
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• v.16 no.3
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• pp.469-474
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• 2006

Partial nitrification blocking of the oxidation of nitrite ($NO_{2}^{-}$) to nitrate ($NO_{3}^{-}$) has cost-efficient advantages such as lower oxygen and organics demand for nitrification and denitrification, respectively. A nitrifying membrane bioreactor of submerged type was operated for the treatment of synthetic ammonium wastewater with the purpose of nitrite build-up without affecting the efficiency of ammonium oxidation. A high ammonium concentration (1,000 mg/l) was completely converted to nitrate at up to 2 kg $N/m^3$ day under sufficient aeration. The control of pH under sufficient aeration was not a reliable strategy to maintain stable nitrite build-up. When the dissolved oxygen concentration was kept at 0.2-0.4 mg/l by adjusting the aeration rate, about 70% of nitrite content was obtained with ammonium oxidation efficiency higher than 93%. The increase of suction pressure due to membrane fouling was not significant under lowered aerating environment over a 6-month period of operation. The composition of nitrifier community, including relative abundance of nitrite oxidizers in a nitrite-accumulating condition, was quantified by fluorescence in situ hybridization analysis.

• Korean Journal of Food Science and Technology
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• v.23 no.6
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• pp.667-672
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• 1991

Varying amount of ginseng was added to pork and chicken breast meat at various pH for a model system. Pork and chicken breast meat sausages were manufactured with 2.5% of ginseng and varying concentration of nitrite. Ginseng reduced the lipid oxidation in the pork except at pH 4.5 whereas promoted in the chicken breast meat regardless of pH. In the presence of ginseng, nitrite decreased the lipid oxidation of the sausages with increasing concentration. Cured color formation increased with an increase of ginseng upto 7.5% in the pork whereas upto 2.5% in the chicken breast meat. Redness of the pork sausage containing ginseng increased with an increase of nitrite. Lightness of the chicken breast meat sausage containing ginseng decreased with increasing nitrite level.

• Bulletin of the Korean Chemical Society
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• v.27 no.2
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• pp.329-332
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• 2006

• The Korean Journal of Ecology
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• v.17 no.3
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• pp.251-260
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• 1994

Nitrification potential bioassay and terpenoid analyses were performed to determine the roles of terpenoid as an inhibitor of nitrification in the Douglas fir (Pseudotsuga menziesii) forests. The effect of terpenoids in the forest floor was also tested by adding $10{\mu}g/ml$ of four terpenoids(${\alpha}-pinene,{\beta}-pinene,{\gamma}-terpinene, and terpinolene) to mineral soils. The amount of terpenoids in the litter was higher than that in the soil and varied over time, but the amount of terpenoids in the soils was relatively constant. The correlation between the amount of terpenoids in the litter and ammonium oxidation was in inverse proportion to that in the mineral layers $(r^2=0.678)$. Inhibition of ammonium oxidation by terpenoids in the litter was always higher than in the mineral layer, but nitrite oxidation was different from the ammonium oxidation. The fact that there was greater nitrate production from ammonium in the mineral layer than in the forest floor layer seems to be due to the less amounts of terpenoids in the mineral layer. The result of the experiment in which four terpenoids were added to the mineral layer suggests that, after some lag time, the four terpenoids were effective in inhibiting ammonium oxidation. However, nitrite oxidation did not appear to be affected by the four terpenoids. Accordingly, all of our results suggested that terpenoids in Douglas fir forests apparently would act as a part of the inhibitors of nitrification.

• Food Science of Animal Resources
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• v.38 no.5
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• pp.1029-1042
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• 2018

This study aimed to investigate the use of golden thread extract (GTE), clove extract (CE), and commercially available nitrite for retarding lipid and protein oxidation and for maintaining color stability and sensory attributes in beef patties stored at $4^{\circ}C$. GTE, CE, and nitrite treatment samples were found to be efficient in retarding lipid oxidation as all three treatments resulted in low thiobarbituric acid reactive substance (TBARS) content (p<0.05). By using GTE, CE, and nitrite into beef patties, protein oxidation was not developed. Incorporation of GTE and CE into beef patties maintained color stability by protecting against the decrease of $L^*$, $a^*$, $b^*$, chroma, and hue angle values and exhibited significant influence on sensory characteristics, including color and odor of beef patties (p<0.05). Compared to commercially available nitrite, GTE and CE were more effective as antioxidants for inhibiting lipid oxidation, and preserving color stability of fresh beef patties. The study indicated that GTE and CE could be utilized efficiently to extend the shelf life of beef patties.

• Journal of the Korean Society of Food Science and Nutrition
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• v.28 no.5
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• pp.984-989
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• 1999

This study was carried out to investigate the effects of ethanol extracts on lipid oxidation of oil emulsion. The results are as follows; The scavenging ability of plant extracts for hydroxyl radical was found, and plant extracts played an important role as a strong chelating agents to bind iron if Fe2+ ion exists in oil emulsion. Pinus densiflora(PD), Lithospermum erythrorhizon(LE) and PD＋LE acted as strong chelating agents to bind iron to reduce lipid oxidation in oil emulsion. The content of Fe2+ ion in ethanol extracts from LE and PD＋LE were significantly higher(p<0.05) than that of ethanol extracts from PD. The content of total iron has same tendency. The ascorbic acid content of PD(16.36ppm) was slightly higher than those of LE(13.08ppm). Electron donating ability of PD was significantly higher(p<0.05) than those of LE. However, the superoxide(SOD) like ability of LE showed a little higher than those of LE and PD＋LE, which means the strong antioxidant activity of LE. The nitrite scavenging effects were dependent on pH value, however, they decreased as pH value increased. Especially, they almost didn't show the nitrite scavenging effect in pH 6.0. In conclusion, the PD and LE extracts may be used as natural antioxidant sources to reduce lipid oxidation in oil emulsion.

• Korean Journal of Food Science and Technology
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• v.19 no.1
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• pp.50-53
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• 1987

The effect of cytochrome on pork fat oxidation was studied either in the absence or in the presence of nitrite and/or ascorbate. Results showed that the back-fat oxidation measured by TBA test increased with increasing concentration of cytochrome c but the Increment decreased with increasing concentration. The addition of ascorbate alone to cytochrome c did not prevent the oxidation. The same result was obtained with the addition of nitrite alone to cytochrome c. However, the backfat oxidation was pretented by the addition of nitrite and ascorbate together With the rendered fat, the trends were more obvious than with backpat.