• Applied Biological Chemistry
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• v.24 no.4
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• pp.230-237
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• 1981

For the investigation of efficient use of fertilizer nitrogen NPK simple trials were carried out using newly bred Tongil line(japonica indica hybrid selection) and the leading local varieties with sulfur coated area in fields for two years. The yield of Tongil line was higher than that of leading local varieties by 16% in the cool year and 23% is warm year with high solar radiation from NPK simple trials including SCU and 2-split application which were carried in 130 fields at 32 locations. Warm year increased yield by 9% in Tongil but only 3% in the local than the cool year did. Optimum nitrogen level was higher in Tongil by 3.8㎏ in the cool year and 5.5㎏ in warm year than for the local. Yearly variation of optimum nitrogen in the carne variety was greater than varietal variation in the same Year. Two-split application resulted in 1 to 2% of inconsistent yield variation. Sulfur coated urea increased yield by average 2 to 4% even at 20% reduced rate of nitrogen. It was remarkably effective in same $(27{\sim}39%)$, virgin (20%) and unmatured (10%) soils.

• Korean Journal of Weed Science
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• v.11 no.3
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• pp.205-210
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• 1991

The freezing resistance of Eleocharis kuroguqai was evaluated in artifical and natural freezing conditions in relation to tuber size, depth of tuber burial and soil moisture conditions. Osmotic potential of immature and mature tuber of E. kuroguqai before hardening was -12.1 and -23.5 bar, respectively, but decreased to -61. 0 and -67.1 bar after 120-day hardening period. Percent survival of E. kuroguqai tubers during the winter period was 13% and 67% in dry and moist moisture conditions at burial of 5cm depth, but all tubers were survived in the three moisture conditions employed when buried at 25cm depth. Greater decrease of osmotic potential was observed in tubers buried at 5cm depth than tubers buried at 25cm depth, resulting in greater freezing resistance in the former. Large tuber was more susceptable to freezing temperatures than small tuber.

• Korean Journal of Environmental Agriculture
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• v.18 no.1
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• pp.70-76
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• 1999

Since high concentrations of N, P, and organic C cause the excessive eutrophication in water systems, the control of nutrient export from agricultural nonpoint sources has become important. This study was conducted to estimate discharges of N, P, and organic C from a small agricultural watershed of the upper Imgo stream in Youngchun, Kyongbuk. Of the total area(1.420ha), 25% was agricultural land including paddy, upland and orchards and most of the remainder was forest. The resident population in the watershed was 194 in 80 households and relatively small numbers of livestocks including cow were raised. Mean concentrations of nutrients in the stream water were 4.95, 0.80, 6.72, 0.07 and 2.52mg/L for $NO_3-N$, $NH_4-N$, Total N, Total P and COD respectively. Annual discharges in 1997 were 28,991kg of $NO_3-N$. 3,010kg of $NH_4-N$, 37,006kg of Total N. 590kg of Total P, and 29,138kg of COD. There was a strong positive relationship between stream flow and precipitation, and also most of the nutrient discharges occurred in the rainy season (May to August). Since there was no any other industries in the watershed, agricultural practices and sewage from the resident households, forest runoff and livestock wastes were the major sources of NPS discharges. A combination of management options, including management of soil erosion and fertilizer application, could lead to reductions in nutrient exports.

• Applied Biological Chemistry
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• v.37 no.4
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• pp.221-225
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• 1994

For producing single cell protein from the agricultural waste, heat treatment and antibiotics on the growth of Cellulomonas sp. KL-6, isolated in rotting leaf and the adjacent soil mixture, were examined. The organism was able to grow until 5 min. at $65^{\circ}C$, 1 min. at $75^{\circ}C$ and 1/4 min. at $85^{\circ}C$ in gradually rising temperatures. It can be Seen that preheating the suspension at $48^{\circ}C$ results in a marked decrease in heat resistance. On heating at temperature of $55^{\circ}C$ for 30 min., strain KL-6 was more resisted in the 0.1 M phosphate buffer when such substrates as casamino acid (1%), yeast extract (1%) or xylose (5%) were added to it whereas this organism was appeared weaker resistances in 0.1 M phosphate buffer when cysteine (0.03 M), sodium citrate (1%) or casein (1%) were in fused into it. Test strain was susceptible to penicillin-G $(1.563\;{\mu}g/ml)$ and ampicillin $(3.125\;{\mu}g/ml)$, but the organism was resisted to kanamycin $(>200\;{\mu}g/ml)$. The treatment of strain KL-6 with sodium dodecyl sulfate (SDS) resulted in the elimination of R-plasmid from the host strain and the elimination rate with SDS $(10{\sim}30\;{\mu}g/ml)$ was about $9.2{\sim}31.2%$, respectively.

• Applied Biological Chemistry
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• v.37 no.4
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• pp.295-302
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• 1994

For the development of biological wastewater treatment process using photosynthetic bacteria (PSB), photosynthetic sludge process consisted of anaerobic digestion and PSB reactor were designed for the treatment of swine wastewater and the optimal operating conditions in flask-scale were examined. Photosynthetic bacteria from soil, pond, rice field, ditch etc. were isolated in synthetic medium containing high amount of organic acids and finally isolated one strain KK14 which showed the most degradating ability of organic acids was selected for the treatment of swine wastewater. It was identified as Rhodopseudomonas palustris. In the anaerobic digestion stage, the maximum organic acid productivity was obtained at pH 5.0, $37^{\circ}C$, HRT 2 day and under anaerobic standing condition. The optimal operating conditions of PSB reactor for the treatment of swine wastewater were pH 7.0, $30^{\circ}C$ under 4,000 lux illumination, and optimal initial COD loading (kg COD/kg D. C. W of PSB) was 2 (20% v/v seeding) in the main purification stage. Maximum removal rate of COD reached 92% under the above optimal conditions for 5 days.

• Applied Biological Chemistry
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• v.36 no.6
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• pp.488-494
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• 1993

A photosynthetic bacterium strain P17 having high growth rate and assimilating ability of organic acids was isolated from several soil samples, which was identified as Rhodospirillum rubrum. Cultural conditions of the strain P17 were examined for the production of starter culture used in the treatment of organic waste water. The addition of organic acids mixture as carbon source containing 0.2% Na-acetate, 0.1% Na-propionate and 0.2% Na-lactate and 0.1% of yeast extract as growth factor stimulated the cell growth. The maximal cell production was obtained at $30^{\circ}C$, pH 7.0, 2,500 lux of illumination and $50{\sim}100\;rpm$ of agitation. Under the optimal conditions of batch and fed-batch culture systems in a Jar fermentor, 5.17 g/l and 7.93 g/l of cells were obtained after S days of cultivation, respectively. In continuous culture system, the cell productivity was 0.206 g/l/h at a dilution rate of 0.21 $h^{-1}$. When R. rubrum P17 was cultivated in a soybean curd waste water, initial COD level(3,240 mg/l) of the waste water was reduced to 250 mg/l after 4 days of cultivation.

• Applied Biological Chemistry
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• v.1
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• pp.12-20
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• 1960

고위생산답(高位生産畓) 22개(個)와 매년(每年) 호마엽고병(胡麻葉枯病)을 발생(發生)시키는 저위생산답(低位生産畓) 18개토양(個土壤)을 분석(分析)하고 활성철(活性鐵)과 열염산(熱鹽酸)에 녹는 철(鐵)의 분포상태(分布狀態)를 조사(調査)하였으며 그 결과(結果)는 아래와 같다. 1. 작토중(作土中)의 활성철(活性鐵)의 함량(含量)과 청취(聽取)한 정조수량간(正粗收量間)에는 밀접(密接)한 정상관(正相關) (${\gamma}=0.68$, 고등(高等)의 유의성(有意性)이 있음)이 있다. 2. 고위생산답(高位生産畓) 토양(土壤)의 활성철(活性鐵) 및 열염산가용철(熱鹽酸可溶鐵)은 저위생산답(低位生産畓) 토양(土壤)에서의 그것보다 현저(顯著)히 많았으며 각(各) 토양별(土壤別) I 층(層)의 그 평균함량(平均含量)과 열염산가용철(熱鹽酸可溶鐵)에 대(對)한 활성철(活性鐵)의 비율(比率)은 아래와 같다. 고위생산답(高位生産畓) 조사점수(調査點數) 활성철(活性鐵)% 활성철(活性鐵)/염산가용철(鹽酸可溶鐵) 잔적토(殘積土) 6 1.313 0.374 하성토(河成土) 9 1.334 0.335 해성토(海成土) 5 1.120 0.382 평균(平均) 20 1.224 0.359 저위생산답(低位生産畓) 조사점수(調査點數) 활성철(活性鐵)% 활성철(活性鐵)/염산가용철(鹽酸可溶鐵) 잔적토(殘積土) 5 1.15 0.370 하성토(河成土) 8 0.472 0.191 해성토(海成土) 5 1.068 0.362 평균(平均) 18 0.808 0.288 그러나 표(表)에서와 같이 잔적토(殘積土) 저위생산답(低位生産畓) 각층(各層)의 철(鐵)은 고위생산답(高位生産畓)에서 보다 낮지 않았다. 3. 해수(海水)의 영향(影響)을 받지 않은 고위생산답(高位生産畓)에서는 표층토(表層土)의 세탈(洗脫)이 적었으나 동(同) 저위생산답(低位生産畓) 및 해성토(海成土)에서는 그 세탈(洗脫)이 크고 동세탈물(同洗脫物)은 심층(心層)에 집적(集積)되여 있다. 4. 해성토(海成土)에서는 고위생산답(高位生産畓)이나 저위생산답(低位生産畓)을 막론(莫論)하고 집적층직하(集積層直下)에 활성철량(活性鐵量)이 심(甚)히 적은 층(層)이 있다. 그리고 집적층(集積層)은 고위생산답(高位生産畓)에서는 II-III층(層)(지표면(地表面)으로부터 60cm이내(以內))에 저위생산답(低位生産畓)에서는 I-II층(層)(지표면(地表面)으로부터 대개(大槪) 30cm이내(以內))에 위치(位置)한다. 5. 같은 고위생산답(高位生産畓) 및 저위생산답(低位生産畓)에서는 토성간(土性間)의 활성철함량(活性鐵含量)에 큰 차이(差異)가 없다. 6. 내산씨(內山氏)의 4개(個)기본(基本)토양형별(土壤型別)로는 동일(同一)토양형((土壤型)이라도 고위(高位) 저위생산답별(低位生産畓別)로 활성철(活性鐵)의 함량(含量)에는 차이(差異)가 크다.

• Applied Biological Chemistry
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• v.46 no.4
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• pp.299-304
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• 2003

A strain YB-9 was isolated from soil as a producer of the extracellular ${\beta}-D-galactosidase$, which catalyzes the hydrolysis of lactose. The strain YB-9 was identified as Streptomyces sp. on the basis of its cultural, morphological and physiological properties. After treating culture supematant of the isolate with ammonium sulfate $(15{\sim}70%)$, the precipitated protein was used as a crude ${\beta}-galactosidase$ for analyzing its reaction properties with $para-nitrophenyl-{\beta}-D-galactoside$ $(pNP-{\beta}Gal)$ and lactose as substrates. The {\beta}-galactosidase showed its maximal activity at pH $6.0{\sim}6.5$ and $60^{\circ}C$. The hydrolyzing activity of ${\beta}-galactosidase$ for both $pNP-{\beta}Gal$ and lactose was decreased by galactose. Its hydrolyzing activity for lactose was slightly decreased by glucose, but the activity for $pNP-{\beta}Gal$ was increased to 1.3-folds by glucose. Especially, its hydrolyzing activity was not affected for lactose and was increased to 1.6-folds for $pNP-{\beta}Gal$ by xylose.

• Applied Biological Chemistry
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• v.51 no.3
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• pp.153-158
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• 2008

An actinomycetes F-97 producing tyrosinase inhibitor was isolated from soil samples. Isolation and purification of tyrosinase inhibitor produced by F-97 was performed as follows: IRC-120 ($NH_4^+$ type) column chromatography, silica gel column chromatography, $C_{18}$ column chromatography and Sephadex LH-20 column chromatography were used successively after the centrifuged supernatant was adjusted to pH 4.0. To identify the purity of the inhibitor, octadecylsilyl(ODS) HPLC was carried out with 5% methanol as a mobile phase. Finally, the purification yield of a tyrosinase inhibitor was 5.24%. The inhibitor was very soluble in water, methanol and ethanol but insoluble in acetone, butanol, ethylacetate and chloroform. The ${\lambda}_{max}$ value of this inhibitor in water was 194nm under UV light. The biochemical test of the inhibitor was positive in Molish, Benedict, cone. $H_2SO_4$, and $KMnO_4$ tests but negative in iodine, ninhydrin, Million, Sakaguchi, xanthoproteic and Emerson tests. The tyrosinase inhibitor was stable against heat treatment of $100^{\circ}C$ for 50 minutes and pH $4{\sim}9$. The $IC_{50}$ value of this inhibitor was $19.2{\mu}g/ml$ for mushroom tyrosinase. In $1,000{\mu}g/ml$ inhibitor concentration, inhibition zone was 27 mm for Streptomyces bikiniensis NRRL B-1049. The inhibition of F-97 against mushroom tyrosinase was competitive with tyrosine.

• Korean Journal of Environmental Agriculture
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• v.12 no.2
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• pp.176-183
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• 1993

Photolysis experiments were conducted to investigate the stability of a new insecticide, [O,O-Diethyl O-(1-phenyl-3-trifluoromethyl-5-pyrazoyl) thiophosphoric acid ester: KH-502] under the various conditions. In the photolysis experiment, KH-502 was, after being added into the acetone or acetonitrile solution, irradiated under the sunlight or UV lamp $(300{\sim}350nm)$, where acetone or acetonitrile solution was varied with water and $O_2$contents and was treated with humic acid, rosebengal or tryptophan. Results for stability and degradation pattern of KH-502 from the above experiment can be summarized as follows: 1. The significant difference in KH-502 decomposition due to photolysis was shown for between KH-502s irradiated at $300{\sim}350$ nm and non-irradiated. KH-502 was photolyzed in the acetone by the sensitizing effect, but was stable in the acetonitrile. 2. The degradation pattern of KH-502 in the photolysis was different as compared to that in the thermal decomposition, and the decomposed products were O,O-Diethyl O-(1-phenyl-3-trifluoromethyl-5-pyrazoyl)phosphoric acid ester (KH-502 oxo form), O,S-Diethyl O-(1-phenyl-3-trifluoromethyl-5-pyrazoyl)phosphorothiolate(S-ethyl KH-502), 1-Phenyl-3-trifluoromethyl-5-hydroxy pyrazole (PTMHP) and several unknown compounds. 3. Treatments of acetone or acetonitrile solution with humic acid, rosebengal or tryptophan revealed no-sensitizing effect on the photolysis of KH-502. Dissolved oxygen in the acetone played as a cosensitizer with acetone competitively to enhance the photolysis of KH-502. 4. Treatments of acetone with humic acid or paddy soil water collected from fields decreased the photolysis of KH-502.