• Journal of the Korea Organic Resources Recycling Association
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• v.15 no.4
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• pp.131-137
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• 2007

In this study, the biodegradation test on lignocellulose under sulfate reducing conditions was carried out. In particular, the interaction between cellulose and lignin was investigated with various g-cellulose/g-lignin (C/L) ratios: 42.15, 4.59, 2.51, 1.14 and 0.7. It was shown that the rate of cellulose degradation decreased in proportion to the lignin content. Assuming first order degradation kinetics, the consequences of competitive inhibition were graphically shown for different C/L ratios. The relation between cellulose reduction rate and C/L ratio was expressed by logarithm function with a determination coefficient of 0.97. Lignocellulose reduction rate was also described as a logarithm function of C/L ratio showing a inhibition effect by lignin. In the mean time, the rate of lignin decomposition was higher at C/L ratio of 2.51 and 1.14 compared with C/L ratios of 4.59 and 0.7, indicating that excessive extra carbon source is not appropriate for lignin biodegradation.

• Microbiology and Biotechnology Letters
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• v.43 no.2
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• pp.164-168
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• 2015

Citric acid is produced via submerged fermentation using yeasts. Among eight different strains of yeast, Candida zeylanoides was chosen as the strain for producing citric acid and optimized for various C/N ratios and effects of phosphate or Fe²⁺ ions in a clean carbon source medium (glucose: fructose, 1:1). The yield of citric acid was maximized at a C/N ratio of 40/1, a phosphate addition of 1.0 g/l, and an Fe²⁺ ion concentration of less than 50 mg/l, yielding up to 91 g/L in the broth with 18.5 g/l of isocitric acid in a six-day fermentation period using a pre-treated molasses medium. The yield of batch culture was 0.51 (Y_p/s, g/g) in a 5 L-Jar fermenter.

• Environmental Analysis Health and Toxicology
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• v.24 no.4
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• pp.341-350
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• 2009

This study involves a relationship between butyltins concentrations and histopathological changes of the digestive gland in the equilateral venus, Gomphina veneriformis exposed to TBTCl of 0.4, 0.6 and 0.8 ${\mu}g/L$ for 36 weeks. In the sediment, total butyltin (${\sum}BT$) concentration was detected ND~7.54 (0.4 ${\mu}g/L$), ND~9.76 (0.6 ${\mu}g/L$), 1.22~13.13 ${\mu}g/L$ (0.8 ${\mu}g/L$), respectively. Especially, TBT level in 0.8 ${\mu}g/L$ group was the highest for 36 weeks. In the soft tissue, total butyltin (${\sum}BT$) concentration of the exposure group was 10.14~12.75 (control), 479.29~1,286.56 (0.4 ${\mu}g/L$), 563.32~2,154.82 (0.6 ${\mu}g/L$) and 1,317.70~2,132.60 ${\mu}g/L$ (0.8 ${\mu}g/L$), respectively. Ratio of TBT to ${\sum}BT$ of the tissue of 0.8 ${\mu}g/L$ kept the lowest level for 36 weeks. The ${\sum}BT$ concentrations of sediment were correlated with ${\sum}BT$ concentrations in the tissue. In the exposure groups, necrosis and atrophy of columnar epithelial cell and collapse of epithelial layer in the digestive tubule. And there was a reduction in stain affinity of basophilic cell. Such histological degenerations was more severe in digestive tubule of 0.8 ${\mu}g/L$ group.

• Resources Recycling
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• v.18 no.4
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• pp.62-69
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• 2009

We researched separation of mixed waste acids with HF, $CH_3COOH$, $HNO_3$ that were produced during a semiconductor wafer process to recycle these acids. At first, we manufactured the fluoride compound in form of $Na_2SiF_6$ by precipitating HF using $NaNO_3$ and Si powder. The concentration of HF was reduced from the initial concentration of 127 g/L to 0.5 g/L with an HF recovery ratio of 99.5%. After the manufacture of $Na_2SiF_6$, the concentration of $HNO_3$ and $CH_3COOH$ demonstrated 502 g/L and 117 g/L respectively. Following these findings we added NaOH in this $CH_3COOH/HNO_3$ mixed acid in order to obtain pH=4. Next we separated the $CH_3COOH$ and recoverd it through the use of vaccum evaporation at -440 mmHg, $95^{\circ}C$. The concentration of the recovered $CH_3COOH$ was approximately 15% and the recovery ratio of $CH_3COOH$ was over 85%. We precipitated the $NaNO_3$ by cooling the concentrated solution to $20^{\circ}C$ with a $HNO_3$ recovery ratio of over 93%. We confirmed that only $Na_2SiF_6$ and $NaNO_3$ were manufactured by XRD analysis after drying these precipitants at $90^{\circ}C$. The precipitants demonstrated a purity of approximately 97% and 98% respectively. Therefore, the purity of the precipitants proved to be similar to that of commercial products.

• Horticultural Science & Technology
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• v.16 no.1
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• pp.42-44
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• 1998

The effect of medium composition on PLB formation and multiplication and shoot regeneration was studied to establish the micropropagation system of the tropical orchid Phalaenopsis. The highest frequence of PLB formation resulted from the VW medium with 1.2 times ion concentration, 1% sucrose, 1.5g/L PVP or 2.5g/L active charcoal, apple and potato extract and 4g/L gellan gum. The highest ratio of PLB multiplication was obtained from the VW medium with 2% sucrose, apple and potato extract and cotton plate. The shoot regeneration was the most effective with the hyponex medium with 3% apple, 3% potato and 4% banana extract.

• Korean Journal of Food Science and Technology
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• v.19 no.5
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• pp.414-419
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• 1987

Cultural conditions for the polysaccharide production by Pseudomonas elodea ATCC 31461, a thermogellable polysaccharide producer, were investigated. Optimum condition for polysaccharide production were: temperature; $30^{\circ}C$, pH; 6.5, glucose; 25 g/L. nitrogen source; peptone, C/N ratio; 5.0. Maximum production and yield at this condition were ca. 32 g/L and 128%, viscosity of 1% polysaccharide solution was 837 mPas at 35/sec.. Consistency index and flow behaviour index were 2570 mPas and 0.66

• Journal of fish pathology
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• v.18 no.3
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• pp.269-276
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• 2005

The concentrations of quinolones (oxolinic acid; OXA, norlloxacin: NRF & ciprofloxacin: CPF) after oral administration of single doses (20 mg/kg B.W.) were investigated in carp (Cyprinus carpio) kept in freshwater at 20-23$^{\circ}C$. The distribution of the drug was studied after treatment. At points timed, from 1 h to 96 hrs after administration, blood (B), liver (L), kidney (K) and muscle (M) from 5 individuals in each group were collected for analyse with microbiological bioassay method. The peak concentrations were measured at 8 h (L), 12 h (B and K) and 24 h (M) after administration regardless of treated drugs. Considerably high concentrations of CPF (13.8-19.6${\mu}g/m{\ell}$) NRF (11.8-16.9${\mu}g/m{\ell}$) and OXA (10.8-13.9 ${\mu}g/m{\ell}$) were revealed during the 24 h. At the last time point of the experiment (96 h), concentrations of all three quinolones were: OXA, 2.3-6.3 ${\mu}g/m{\ell}$ ; NRF, 3.1-4.5 ${\mu}g/m{\ell}$ ; CPF, 3.0-5.5${\mu}g/m{\ell}$ in samples. The concentrations decreased subsequently, indicating a first rapid redistribution, followed by a slow phase of elimination. The steady state was observed in blood (12-36 h), liver (12-96 h) and muscle (36-96 h) after the initiation of treatment with OXA. Concerning the compartmental concentrations, (L, K. and M/B concentration ratio), the fluctuation of the ratio was founded at different time points, among drugs. For CPF, highest tissue ratios were prolonged in the order of L>K>M (0.65-1.2/0.82-0.93/1.0-1.7) during the experiments. On the other hand, NRF presented L>K>M (0.65-1.3/0.86-1.0) till 24 h, but L>M>K (0.89-1.26) at 36-96 h. OXA showed L>K>M (0.95-2.1) at 1-8 h, M>K>L (0.51-1.0) at 12-36 hand M>L>K (1.0-2.3) at 48-96 h, respectively.

• Earthquakes and Structures
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• v.24 no.6
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• pp.455-475
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• 2023

The present study investigates the non-linear soil-pile interaction using three-dimensional (3D) non-linear finite element models. The numerical models were validated by using the results of extensive pile load and shaking table tests. The pile performance in liquefiable and non-liquefiable soil has been studied by analyzing the liquefaction ratio, pile lateral displacement (LD), pile bending moment (BM), and frictional resistance (FR) results. The pile models have been developed for the different ground conditions. The study reveals that the results obtained during the pile load test and shaking cycles have good agreement with the predicted pile and soil response. The soil density, peak ground acceleration (PGA), slenderness ratio (L/D), and soil condition (i.e., dry and saturated) are considered during modeling. Four ground motions are used for the non-linear time history analyses. Consequently, design charts are proposed depended on the analysis results to be used for design practice. Eleven models have been used to validate the capability of these charts to capture the soil-pile response under different seismic intensities. The results of the present study demonstrate that L/D ratio slightly affects the lateral displacement when compared with other parameters. Also, it has been observed that the increasing in PGA and decreasing L/D decreases the excess pore water pressure ratio; i.e., increasing PGA from 0.1 g to 0.82 g of loose sand model, decrease the liquefaction ratio by about 50%, and increasing L/D from 15 to 75 of the similar models (under Kobe earthquake), increase this ratio by about 30%. This study reveals that the lateral displacement increases nonlinearly under both dry and saturated conditions as the PGA increases. Similarly, it is observed that the BM increases under both dry and saturated states as the L/D ratio increases. Regarding the acceleration histories, the pile BM was reduced by reducing the acceleration intensity. Hence, the pile BM decreased to about 31% when the applied ground motion switched from Kobe (PGA=0.82 g) to Ali Algharbi (PGA=0.10 g). This study reveals that the soil conditions affect the relationship pattern between the FR and the PGA. Also, this research could be helpful in understanding the threat of earthquakes in different ground characteristics.

• 한국생물공학회:학술대회논문집
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• 2003.04a
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• pp.600-604
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• 2003

This study pointed at isolation of bunker-C oil degrading bacteria and then estimation of it's degrading capability in environmental conditions. Degradation ratio of the excellent isolate was appeared to 40.5% and 44.7% when the oil was treated to 1% and 5%, respectively. The isolate was identified to Acinetobater calcoaceticus SEBCM. In pH test, high degrading effect was appeared to about 73% at pH 6 and pH 7, and low degrading ratio was 37% at pH 4. Its growth condition at temperature has not large variation in $15^{\circ}C\;{\sim}30^{\circ}C$, Quantity of nitrogen for it's good growth was ranged of $0.5\;g/L{\sim}2\;g/L$. As these results, we realized that this isolate have good activity when treated to $15\;{\sim}30^{\circ}C$ of temperature and $6{\sim}7$ of pH.

• Applied Biological Chemistry
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• v.36 no.1
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• pp.38-44
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• 1993

1) OBT7 mutant was isolated by W light-butanol tolerance from Clostridium saccharoperbutylacetonicm ATCC 13564 (N1-4 strain). The mutant produced 16.5 g/l (1.4-fold increase) of n-butanol, 4.65 g/l (1.5-fold increase) of acetone, and 21.5 g/l of total solvent. It was suggested that clostridial bacteria producing n-butanol does not have a poor effect on misrepair via an error-prone pathway by UV light-butanol tolerance. 2) Compared to glucose fermentation, in mannitol fermentation, OBT7 mutant did not produce acetone and acetic acid. And the ratios of n-butanol and ethanol to total solvents increased by 10.3% and 10.5%, respectively, totalling 20.8%, while the ratio of acetone was decreased by 21.2%. Also the maximum ratio of n-butanol to total solvents reached 94.8%. These results indicated that oxidized compound (acetone, acetic acid, and butyric acid) was converted to the reduced compounds (n-butanol, and ethanol). Therefore, mannitol can be used to eliminate by-products of oxidized compound.