• Korean Journal of Soil Science and Fertilizer
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• v.17 no.3
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• pp.218-223
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• 1984

In order to analyze the effects of percolation rate on the growth and yield of rice plants in paddy soils, pot (1a/2000) experiments were carried out. The soil used was highly concentrated with various salts in the horticulture area under vinyl house cultivation, and Samgang variety of Japanica rice was planted. With the increasing rates of percolation, $SiO_2$ and $Ca^{2+}$ were more leached out from soils than supplied by irrigation while $K^+$ and $NH_4{^+}$ were more supplied to soils than leached out. The root activity in the late growth stage was higher in the percolation pots than in the non-percolation pots. Amounts of nutrient uptake of T-N, $P_2O_5$, $K_2O$ and MgO were increased gradually with the increase of percolation rate, but that of $SiO_2$ was maximum at 10mm per day. The percolation rate of 5~10mm per day was considered to be the optimum condition for obtaining more than 95% of relative yield in rice cultivation.

• Korean Journal of Food Science and Technology
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• v.37 no.3
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• pp.449-455
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• 2005

To reduce saft content of kochujang, various combinations of sub-materials such as ethanol mustard and chitosan were added to kochujang, and their effects on microbial characteristics, enzyme activities, and physicochemical characteristics of kochujang were investigated after 12 weeks of fermentation. Activities of ${\beta}$-amylase and pretense were low in ethanol-mustard-chitosan-added kochujang, whereas no significant difference was observed in ${\alpha$-amylase activity among all groups. Number of viable yeast cells decreased remarkably in mustard-added kochujang during late aging period, and anaerobic bacterial counts decreased in sub-material-added groups. Consistency of kochujang increased by addition of sub-materials, and oxidation-reduction potential was low in chitosan-added group. Mustard-chitosan-added kochujang showed lowest increase in total color difference(${\Dalta}E$) and decrease in water activity. PH of kochujang wns highest in mustard-chitosan-added kochujang, resulting in significantly increased titratable acidity. Addition of sub-material increased reducing sugar contents of kochujang, whereas ethanol production was significantly repressed in mustard-chitosan-added kochujang. Amino nitrogen content was Highest in mustard-chitosan-added kochujang during late aging period, whereas ammonia nitrogen content was lower in ethanol-mustard-added kochujang. Results of sensory evaluation indicated ethanol-mustard-added kochujang was more acceptable than other groups in taste and overall acceptability.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.25 no.5
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• pp.371-382
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• 1992

Biochemical composition, the rates of nitrogen excretion in the form of ammonia, amino acids and total nitrogen, and oxygen consumption of the shrimp Crangon affinis were measured at three temperature regimes $(7,\;15,\;and\;25^{\circ}C)$ and the variations were also determined for starvation periods (1-25 days). The composition of the major biochemical fractions was analysed into carbohydrate: $4.2\%,\;protein:\;68.6\%,\;lipid:\;7.0\%,\;chitin:\;6.3\%,\;and\;ash:\;14.6\%,$ all expressed as percentage of dry weight. Molting frequency was lower at $7^{\circ}C\;than\;25^{\circ}C$ during the period of starvation, and during the same period the higher temperature was, body weight and body compositions the more decreased. Through all starvation periods $O_2$ consumption tended to decrease but total nitrogen tended to increase at any temperature regimes. The dominant form of excreted total nitrogen was ammonia-N at any temperature. From the O:N ratio it appeared that carbohydrate and lipid reserves were quickly exhausted (1-5 days), and that proteins were the substrates oxidized to meet the energetic requirements of C. affinis at any temperature. After 25 days of starvation the O:N ratio remained constant near a value of 8, which indicates that only proteins were being utilized at three temperatures. After 25 days of starvaion C. affinis excreted 23.01ug N/mg body nitrogen per day at $7^{\circ}C,\;32.97\mu g\;N/mg$ body nitrogen per day at $15^{\circ}C,\;and\;44.81\mu g\;N/mg$ body nitrogen per day at $25^{\circ}C$, and lost about 1.75, 2.47 and $3.29^{\circ}C$ of body protein per day at 7, 15, and $25^{\circ}C$ respectively.

• Korean Journal of Soil Science and Fertilizer
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• v.42 no.2
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• pp.117-122
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• 2009

This study was carried out to investigate applicability of Spent Mushroom Media(SMM) as horticultural nursery media. After the mushroom has been harvested, the SMM contains a lot of organic material, different microorganism and high density of mushroom hypha. The pH, phosphate and exchangeable cation concentrations of SMM of Flammulina velutipes were higher than those of any other treatment. The CEC and $NH_4-N$ were the highest in SMM of bottle-cultivated oyster mushroom (Pleurotus ostreatus). Bacteria and fungi showed the highest density in SMM of Flammulina velutipes. Most dominant bacteria were Microbacterium sp., Rhodococcus sp. and Agrobacterium sp. in SMM of Flammulina velutipes and Bacillus sp., Pseudomonas sp., Curtobacterium sp. and Microbacterium sp. in that of Pleurotus eryngii. The SMM contained high density of mushroom hypha that inhibited germination of seed and growth of young seedlings. Therefore, composting process of the SMM is indispensible to decline of vitality of mushroom hypha. The SMM of Flammulina velutipes with 0~30% vermiculite showed high germination rate in red pepper and chinese cabbage seeds. SMM of Pleurotus eryngii with 20% vermiculite showed 100% germination rate in red pepper seeds, but chinese cabbage seeds nearly failed to germinate with 30% vermiculite. The growth of red pepper was increased according to increasing mixture ratio of vermiculite. Accordingly, we concluded that SMM of Flammulina velutipes contained 0~30% of vermiculite can be used to horticultural growth bed for red pepper.

• Korean Journal of Food Science and Technology
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• v.35 no.3
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• pp.461-469
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• 2003

Effects of fruit of Lycium chinense (Chinese matrimony vine) on enzyme activities, and microbial and physicochemical properties of kochjuang were investigated during 12 weeks of fermentation. Enzyme activities were higher during middle of fermentation, and protease activities increased as the ratio of L. chinense increased. Facultative anaerobic bacteria counts decreased in L. chinense-added kochujang, whereas viable cell count of yeasts was higher in 1% L. chinense-added kochujang. Consistency of kochujang decreased by addition of L. chinense. Hunter L- and a-values of L. chinense added kochujang were high, causing slight change in total color difference (E) as the ratio of L chinense increased. Moisture contents of kochujang increased during fermentation, whereas water activities decreased. As the ratio of L. chinense increased, water activities increased. Titrable acidities and oxidation-reduction potential increased by addition of L. chinense. Total sugar contents of kochujang decreased rapidly during fermentation, whereas reducing sugar contents increased up to $2{\sim}4$ weeks of fermentation. As the ratio of L. chinense increased, reducing sugar contents decreased. Ethanol contents of kochujang increased during fermentation, with higher values in 3% L. chinense-added kochujang. Amino and ammonia nitrogen contents of kochujang increased L. chinense content increased. After 12 weeks of fermentation, sensory results showed 3% L. chinense-added kochujang showed highest taste and overall acceptability, and color acceptability increased as L. chinense content increased.

• Journal of Life Science
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• v.23 no.4
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• pp.529-536
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• 2013

This study was carried out to investigate the characteristics of white soybean Chungkookjang fermented by Bacillus subtilis D7. The highest germination rate was obtained under $25^{\circ}C$ when water was supplied for 4 days at intervals of 2 hr. The total isoflavone content was 971.3 ${\mu}g/g$ before germination and 1023.8 ${\mu}g/g$ after germination. The amino type- and ammonia type-nitrogen contents of Chungkookjang were proportional to the fermentation time. The pH values of all Chungkookjang soybeans increased up to pH 7.8-8.0 during fermentation. The number of viable cells in all Chungkookjang soybeans increased significantly up to 24 hr. The protease activity of all Chungkookjang soybeans increased up to 30-36 hr. The ${\alpha}$- and ${\beta}$-amylase activities of Chungkookjang fermented by B. subtilis D7 were enhanced with increasing fermentation time. Analysis of the effect of Chungkookjang intake on the liver function of mouse showed that the alkaline phosphatase (ALP) activity and the superoxide dismutase (SOD) activity in the Chungkookjang diet group were markedly higher than those in the control group. The asparatate aminotransferase (AST) activity in the germinated soybean Chungkookjang diet group was higher than that in the nongerminated soybean Chungkookjang diet group. Therefore, Chungkookjang soybeans fermented with B. subtilis D7 can be expected to have an increased content of functional components and improved quality characteristics.

• Korean Journal of Food Science and Technology
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• v.34 no.5
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• pp.811-817
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• 2002

Korean traditional soy sauce was desalted using electrodialyzer, and their physicochemical properties were analyzed. The salt content of soy sauce significantly decreased from initial 18.9 (w/v) to 0.47% (w/v) and the volume also decreased to 330 mL when 1,000 mL of soy sauce was desalted for 450 min at a current of 2 A. During the desalting process, the numbers of viable cells of total bacteria, yeasts, and molds increased due to the concentration effect of the electrodialysis. Turbidity increased from 3.1 to 8.5, and total nitrogen, total sugar, and reducing sugar contents also increased. The pH, and amino nitrogen and volatile base nitrogen contents slightly decreased, with ammonia content significantly decreasing from 19.4 to $1.3\;{\mu}mol/mL$. Free amino acids content increased twofold after electrodialysis. Gas chromatograms of soy sauce showed that profiles of the flavoring compounds did not change when electrodialyzed for 360 min, but most were removed after 540 min.

• Resources Recycling
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• v.28 no.3
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• pp.15-20
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• 2019

The recovery of struvite using nitrogen and phosphorus in wastewaters is useful for prevention of eutrophication and use as fertilizer, but there are theoretical and technical issues to be resolved. Through the detailed literature review, this study discusses the possible reasonable prediction of struvite formation reaction by setting a feasible reaction equation with some theoretical considerations. In a technical aspect, the purity of struvite in solid precipitates can be promoted by excluding Ca in an effective way. As for the struvite reaction prediction issue, selection of proper equilibrium reaction as well as its reaction equilibrium coefficient is significant in the neutral and basic pH regions. The equilibrium reaction agrees well with the experimental batch test results. Considering the charge balance of the ions, the pH drop along struvite formation in a diluted solution can be predicted. Also, improvement of struvite purity through elimination of Ca can be expected by providing a highly concentrated ${NH_4}^+-N$ relative to ${HPO_4}^{2-}-P$ because ${NH_4}^+$ can enhance the thermodynamic driving force toward favorable struvite formation. Even though the phosphate reacts rapidly with Ca to form a solid precipitate, the thermodynamic driving force due to the high ${NH_4}^+$ activity can dissociate the phosphate-calcium precipitates and produce struvite.

• Korean Journal of Soil Science and Fertilizer
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• v.33 no.1
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• pp.52-60
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• 2000

This study was conducted to gain basic data for alleviation of gas emission and conservation of healthy soil environment by investigating an aspect of gas emission and microbial diversity due to the supplement of different fertilizers after application with a livestock manure compost in greenhouse soils. Green pepper was cultivated in clay loamy soil from April to August. Before planting, a livestock manure compost was applied with $741mg\;ha^{-1}$ on the basis of the phosphate content contained in compost. And then, deficient nitrogen for cropping was supplemented with either quick-acting fertilizer of urea or a controlled slow release fertilizer made from urea formaldehyde(U/F). $NH_3$ and R $NH_2$ gases emitted from soil showed a low concentration in the early stage but a maximum in 27 days after planting, then decreased rapidly and not detected after 33 days. Their average concentrations were 42% and 85% lower in the treatment of slow release fertilizer than that of urea fertilizer, respectively. $CO_2$ gas emitted under urea fertilization was ranged from 1,200 to $3,200mg{\ell}^{-1}$ and that in slow release fertilizer was $900{\sim}2,650mg\;{\ell}^{-1}$. The average concentration of urea treatment was $2,260mg{\ell}^{-1}$ and 30% higher than that of slow release fertilizer. The treatment of slow release fertilizer with the lapse of cropping time populated larger in numbers of bacteria, actinomycetes, nitrate bacteria and nitrate reduction bacteria, and ratios of bacteria and actinmycetes to fungi than that of urea fertilizer. But the number of fungi was higher in the treatment of urea fertilizer and denitrifying bacteria showed a similar trend in both treatments. The microbial diversity index, which calculated with numbers of 6 species of microorganisms, was decreased with increasing of growing stage in the range of 0.1 to 0.35 and that was higher in the tratment of slow release fertilizer than urea.

• Journal of Aquaculture
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• v.22 no.1
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• pp.42-50
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• 2009

Shrimp farming which is entirely conducted in outdoor ponds in the west coast of Korea has been suffered from mass mortality due to viral epizootics. Intensive indoor shrimp culture under limited water exchange can solve these problems of outdoor ponds including viral transmission from environment, pollution due to discharge of rearing water, low productivity and limited culture period. In this study, juvenile L. vannamei (B.W. 0.08-0.09 g) was stocked with $3,000-5,455/m^3$ in density in four raceway tanks (two $12.9\;m^2$, two $18\;m^2$ tanks) and cultured for 42 days with 2.7-3.4% of daily water exchange. Results from four tanks showed FCR of 0.79-1.29, survival of 38.2-48.0%, and yields of $2.49-4.22\;kg/m^3$ which is consistent with 12-20 and 8-14 times higher than those of commercial shrimp hatchery and outdoor pond in Korea, respectively. Concentrations of total ammonia nitrogen in all four tanks were 1.11-1.42 ppm in mean level and did not exceed 6.0 ppm (0.096 ppm of $NH_3$) which is still acceptable levels for shrimp growth. During the culture trial, concentration of $NO_2$-N rapidly increased from stocking, resulting in mean concentration of 18.45-22.07 ppm. It also exceeded 10 ppm over four weeks and maintained at 35-45 ppm for four days in all tanks, accounting for low survival of shrimp due to long-term exposure to high concentration of $NO_2$-N. Nevertheless, the results with survival rate over 38% from raceways which experienced the extreme $NO_2$-N levels suggests that under "biofloc system" white shrimp can acclimate to high $NO_2$-N concentration to some degree.