• Asian-Australasian Journal of Animal Sciences
• /
• 제5권1호
• /
• pp.113-121
• /
• 1992

An the livestock production in Japan is industrialized, a tremendous amount of animal wastes is being produced annually, resulting in serious environmental pollution problems. Animal wastes could be pollutants, but they are also important sources of fertilizer nutrients and organic matter. Composting is an effective way of promoting the increased utilization of animal wastes. The characterization of maturing process during composting is important in order to improve the composting technology and to develop and efficient method to estimate the degree of maturity. The rise and fall in temperature, and changes in the constituents of the compost, reflect the maturing process and may serve as indicators for maturation. In addition, the detection of nitrate by diphenylamine, the determination of cation-exchange capacity (CEC), and the germination test, are also recommended as the methods of estimating the degree of maturity. The heavy applications of animal manure and compost may cause an adverse effect on soils and crops. When excess manure is applied, the nitrogen will be accumulated in soil, resulting in accumulation of nitrate in crops and pollution of the groundwater. Guidelines for application rates are recommended, to maintain soil productivity and quality of crops, and to prevent the environmental pollution.

• Journal of Microbiology and Biotechnology
• /
• 제18권12호
• /
• pp.1958-1965
• /
• 2008

A denitrifying polyphosphate-accumulating bacterium (YKP-9) was isolated from activated sludge of a 5-stage biological nutrient removal process with step feed system. This organism was a Gram-negative, coccus-shaped, facultative aerobic chemoorganotroph. It had a respiratory type of metabolism with oxygen, nitrate, and nitrite as terminal electron acceptors. The 16S rRNA gene sequence of strain YKP-9 was most similar to the 16S rRNA gene sequence of Paracoccus sp. OL18 (AY312056) (similarity level, 97%). Denitrifying polyphosphate accumulation by strain YKP-9 was examined under anaerobic-anoxic and anaerobic-oxic batch conditions. It was able to use external carbon sources for polyhydroxyalkanoates(PHA) synthesis and to release phosphate under anaerobic condition. It accumulated polyphosphate and grew a little on energy provided by external carbon sources under anoxic condition, but did neither accumulate polyphosphate nor grow in the absence of external carbon sources under anoxic condition. Cells with intracellular PHA cannot accumulate polyphosphate in the absence of external carbon sources under anoxic condition. Under oxic condition, it grew but could not accumulate polyphosphate with external carbon sources. Based on the results from this study, strain YKP-9 is a new-type denitrifying polyphosphate-accumulating bacterium that accumulates polyphosphate only under anoxic condition, with nitrate and nitrite as the electron acceptors in the presence of external carbon sources.

• Environmental Engineering Research
• /
• 제25권3호
• /
• pp.274-280
• /
• 2020

The marine sediment sustains from the anoxic condition due to increased nutrients of external sources. The nutrients are liberated from the sediment, which acts as an internal source. In hypoxic environments, anaerobic respiration results in the formation of several reduced matters, such as N₂ and NH₄⁺, N₂O, Fe²⁺, H₂S, etc. The experimental results have shown that nitrogen and sulfur played an influential, notable role in this biogeochemical cycle with expected chemical reductions and a 'diffusive' release of present nutrient components trapped in pore water inside sediment toward the bulk water. Nitate/ammonium, sulfate/sulfides, and ferrous/ferric irons are found to be the key players in these sediment-waters mutual interactions. Organonitrogen and nitrate in the sediment were likely to be converted to a form of ammonium. Reductive nitrogen is called dissimilatory nitrate reduction to ammonium and denitrification. The steady accumulation in the sediment and surplus increases in the overlying waters of ammonium strongly support this hypothesis as well as a diffusive action of the involved chemical species. Sulfate would serve as an essential electron acceptor so as to form acid volatile sulfides in present of Fe³⁺, which ended up as the Fe²⁺ positively with an aid of the residential microbial community.

• 공업화학
• /
• 제33권2호
• /
• pp.222-228
• /
• 2022

As a possible feedstock for biodiesel, the marine green alga Tetraselmis sp. was cultivated under different conditions of phototrophic, mixotrophic and heterotrophic cultures. Glycerol, a byproduct from biodiesel production process, was used as the carbon source of mixotrophic and heterotrophic culture. The effects of glycerol supply and nitrate-repletion were compared for different trophic conditions. Mixotrophic cultivation exhibited higher biomass productivity than that of phototrophic and heterotrophic cultivation. Maximum lipid productivity of 55.5 mg L^-1 d^-1 was obtained in the mixotrophic culture with 5 g L^-1 of glycerol and 8.8 mM of nitrate due to the enhancement of both biomass and lipid accumulation. The major fatty acid methyl esters (FAME) in the produced biodiesel were palmitic acid (C16:0), oleic acid (C18:1), linoleic acid (C18:2), and linolenic acid (C18:3). The degree of unsaturation was affected by different culture conditions. The biodiesel properties predicted by correlation equations based on the FAME profiles mostly complied with the specifications from the US, Europe and Korea, with the exception of the cold-filter plugging point (CFPP) criterion of Korea.

• 한국산림과학회지
• /
• 제81권2호
• /
• pp.183-190
• /
• 1992

기내배양된 현사시나무의 조직배양세포로부터 안토시아닌 생성과 세포생장에 적합한 요인을 구명하여 차후 기내배양을 통한 2차대사산물생산의 기초자료를 제공하고자 연구를 수행하였다. Callus는 0.5mg/l 2, 4-D, 0.1mg/l BAP을 첨가한 MS배지에서 유발시켜 같은 배지에서 증식하였다. 안토지아닌 생산은 MS 기본배지를 기준으로 하여 질산염은 12.5% 감량시키고 인산염은 400%로 증가시켜 5% sucrose와 1.0mg/l IAA 및 1.0mg/l BAP를 첨가한후 7,000 lux의 연속광 하에서 배양했을 때 가장 높게 나타났다. 그러나 세포의 생장은 MS 기본배지를 기준으로 하여 질산염은 50% 감량시키고 인산염은 400%로 증가시켜 5% sucrose와 0.5mg/l 2, 4-D를 첨가한 배지에서 가장 양호한 결과를 얻었다. 안토시아닌의 동정은 1% 염산-메탄올의 유기용매로 추출하여 정제 후 TLC와 UV spectrophotometer로 확인한 결과 pelargonidin 3-rhamnoside-5-glucose로 추정되었다.

• 한국해양바이오학회지
• /
• 제6권2호
• /
• pp.110-117
• /
• 2014

Recently microalgae have been proposed as a promising biodiesel feedstock, owing to their higher lipid productivity and non-arable land based cultivation system. Biomass and lipid productivities of microalgae are largely affected by various environmental and nutritional factors. In this study, the effects of nitrogen (nitrate and ammonium) and organic carbon (glucose and glycerol) sources on the cell growth and lipid production of Chlorella sp. KR-1 were examined in flask cultures. Under autotrophic culture conditions for 15 days, overall cell growth and lipid (fatty acid methyl ester, FAME) production with nitrate were better than those of ammonium, resulting in 1.06 g cell/L and 333 mg FAME/L, respectively. Maximal intracellular lipid contents (348 - 352 mg FAME/g cell) were observed at low concentrations of 1 mM for both nitrate and ammonium. In the supply of light, addition of glucose in the range of 1 - 20 g/L showed higher cell densities than the autotrophic cell growth condition. Higher lipid accumulation of 375 mg FAME/g cell could achieved at 5 g glucose/L albeit of relatively short incubation of 7 days. With glycerol, intracellular lipid contents were ~1.9 times lower than glucose cases although similar cell growths were observed for both carbon sources.

• 한국환경농학회지
• /
• 제19권4호
• /
• pp.294-299
• /
• 2000

차광 및 질소시비량이 상추의 엽내 $NO_3\;^-$ 축적에 미치는 영향을 구명하기 위하여 질소 시비량을 달리하여(100, 180, 200, 300, $400\;kg{\cdot}ha^{-1}$) 50% 차광 과 무차광 상태에서 상추를 재배하였다. 1. 시험전 토양에 비하여 시험후 토양에서 pH는 낮아진 반면 EC 및 $NO_3-N$ 함량은 높아졌다. 질소 시비량이 증가할수록 pH는 낮아지는 경향이며, EC 및 $No_3\;^-$ 함량은 높아지는 경향이었다. 또한, 시험후 토양에서 $NO_3-N$ 함량이 증가할 수록 EC가 높아졌다. 2. 질소시비량이 100, 180, 200, 300 그리고 $400kg{\cdot}ha^{-1}$에서 상추의 입모율은 각각 84, 78, 76, 72 및 74% 이었고, 생존율은 각각 94, 94, 90, 60 및 46%로서 질소시비량이 증가할수록 입모율 및 생존율이 감소하였다. 상추의 생산량은 무차광 재배에서 진단시비($180\;kg{\cdot}ha^{-1}$)에서 $45\;g{\cdot}$주$^1$ 로서 가장 높았다. 3. 상추 엽중 $NO_3\;^-$ 함량은 질소시비량이 증가할수록 높아졌고 또한 무차광에 비하여 50% 차광에서 $2.8{\sim}4.1$배 높았으며, 엽위별로의 $NO_3\;^-$ 함량은 7엽기까지 증가하다가 8엽기부터 감소하였다. 4. NRA은 50% 차광보다 무차광에서 높게 나타났다.

• 자연과학논문집
• /
• 제6권1호
• /
• pp.49-54
• /
• 1993

사과나무에 대한 칼슘용액의 수관살포 시 칼슘염의 종류에 따른 과실 내 칼슘함량증가효과를 구명하고 자 본 연구를 수행하였다. $CaCl_2$, $CaCO_3$, Ca$(CH_3COO)_2$ 및 Ca$(NO_3)_2$ 등의 칼슘염을 수관살포한 결과 "쓰가루" 품종에는 Ca$(NO_3)_2$, $CaCl_2$ 및 $CaCO_3$, 그리고 "후지" 품종에는 $CaCl_2$와 $CaCO_3$가 과실의 칼슘함량증가에 효과적이었다. 수관살포에 의하여 과실로 흡수된 칼슘은 과피와 과피직하의 과육에 국한되었다. Ca$(CH_3COO)_2$를 살포한 과실은 저장 중에 에틸렌 발생량이 감소하는 경향이었다.

• 한국토양비료학회지
• /
• 제20권1호
• /
• pp.35-41
• /
• 1987

질산태질소(窒酸態窒素)를 선택흡수(選擇吸收)하는 담배식물에 대하여 흡수된 $NO_3-N$의 각조직별(各組織別) 이동양상(移動樣相)과 질산환원효소(窒酸還元酵素)의 활성도(活性度)(nitrate reductase activity. NRA)를 조사하고 생육과정(生育過程)에서 출엽(出葉)된 잎들의 질산환원능력(窒酸還元能力)을 비교조사(比較調査)한 결과(結果) 1. 도관조직(導管組織)인 엽맥(葉脈)까지는 함유(含有)된 질소(窒素)의 대부분(大部分)이 $NO_3-N$으로써 무기태질소(無機態窒素)로 엽맥(葉脈)을 통과(通過)하며 엽육(葉肉)에서는 $NO_3-N$이 환원(還元)되어 무기태질소(無機態窒素)가 거의 검출(檢出)되지 않았다. 2. NRA는 성숙(成熟)된 잎에서 가장 왕성하였으며 분열생장중(分裂生長中)인 잎이나 도관조직(導管組織)에서는 환원기능이 매우 낮은 수준에 머물렀다. 3. 하위(下位)의 성숙엽(成熟葉)은 두껍고 수분(水分)을 많이 함유(含有)하였으며 가장 왕성한 질산환원능력(窒酸還元能力)을 보였다. 4. 생장조직(生長組織)으로 유기질소물질(有機窒素物質)을 공급(供給)하기 위하여 유식물(幼植物)때는 소수(小數)의 좁은 잎에서 높은 수준(水準)의 NRA를 유지(維持)했으나 생육(生育)이 진전되어 많은 잎이 착엽(着葉)되면서 상위(上位)쪽의 성숙엽(成熟葉)은 NRA가 낮은 수준에 머물렀다.

• 한국환경과학회지
• /
• 제21권12호
• /
• pp.1455-1462
• /
• 2012

The vertical distributions of nitrifying bacteria in aerobic fixed biofilm were investigated to evaluate the relationship between nitrification performance and microbial community at different HRT. Fluorescent in situ hybridization (FISH) and portable ion selective microelectrode system were adopted to analyze microbial communities and ions profiles according to the biofilm depth. Cilia media packed MLE (Modified Ludzack-Ettinger) like reactor composed of anoxic, aerobic I/II was operated with synthetic wastewater having COD 200 mg/L and $NH_4{^+}$-N mg/L at HRT of 6 hrs and 4 hrs. Total biofilm thickness of aerobic I, II reactor at 4 hrs condition was over two times than that of 6 hrs condition due to the sufficient substrate supply at 4 hrs condition (6 hrs; aerobic I 380 ${\mu}m$ and II 400 ${\mu}m$, 4 hrs; aerobic I 830 ${\mu}m$ and II 1040 ${\mu}m$). As deepen the biofilm detection point, the ratio of ammonia oxidizing bacteria (AOB) was decreased while the ratio of nitrite oxidizing bacteria (NOB) was maintained similar distribution at both HRT condition. The ratio of AOB was higher at 4 hrs than 6 hrs condition and $NH_4{^+}$-N removal efficiency was also higher at 4 hrs with 89.2% than 65.4% of 6 hrs. However, the ratio of NOB was decreased when HRT was reduced from 6 hrs to 4 hrs and $NO_2{^-}$-N accumulation was observed at 4 hrs condition. Therefore, it is considered that insufficient HRT condition could supply sufficient substrate and enrichment of AOB in all depth of fixed biofilm but cause decrease of NOB and nitrite accumulation.