• 상하수도학회지
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• 제7권1호
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• pp.20-28
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• 1993

The Wastewater from the weight reduction process of polyester is more difficult to be treated biologically than the general wastewater from dyeing and finishing processes in textile industries. Above wastewater shows high pH, high organic strength and wide variation of organic loading. These characteristics are due to TPA and EG resulting from alkaline weight-reduction process and make trouble in the operation of activated sludge process. Therefore, the objective of this study is to develop the pretreatment method for the successful operation of treatment process. For the successful pretreatment process, the wastewater from weight-reduction process should be segregated from other wastewater stream and then acidified with concentrated sulfuric acid to precipitate out TPA from DST solution. At the optimum pH of 2. 2, the initial $COD_{cr}$ 60,000mg/l is reduced to 11,500mg/l and the removal efficiency of $COD_{cr}$ is 81.1%. The required amount of sulfuric acid for pretreatment is not greater than the amount for the the existing neutralization process. Moreover, the supernatant of pretreatment process can be reused in acidification of wastewater.

• Journal of the Korean Wood Science and Technology
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• 제52권2호
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• pp.101-117
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• 2024

The conversion characteristics of the major components of Liriodendron tulipifera were investigated during acid-catalyzed organosolv pretreatment. Glucan in L. tulipifera was slowly hydrolyzed, whereas xylan was rapidly hydrolyzed. Simultaneous hydrolysis and degradation of xylan and lignin occurred; however, after complete hydrolysis of xylan at higher temperatures, lignin remained and was not completely degraded or solubilized. These conversion characteristics influence the structural properties of glucan in L. tulipifera. Critical hydrolysis of the crystalline regions in glucan occurred along with rapid hydrolysis of the amorphous regions in xylan and lignin. Breakdown of internal lignin and xylan bonds, along with solubilization of lignin, causes destruction of the lignin-carbohydrate complex. Over a temperature of 160℃, the lignin that remained was coalesced, migrated, and re-deposited on the surface of pretreated solid residue, resulting in a drastic increase in the number and content of lignin droplets. From the results, the characteristic conversions of each constituent and the changes in the structural properties in L. tulipifera effectively improved enzymatic hydrolysis in the range of 140℃-150℃. Therefore, it can be concluded that significant changes in the biomass recalcitrance of L. tulipifera occurred during organosolv pretreatment.

• Food Science and Biotechnology
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• 제17권3호
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• pp.534-539
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• 2008

This study investigated the effects of pretreatment and storage conditions on the properties of stored chestnuts. Effects on chestnuts of refrigerated storage (RNT) and frozen storage (FNT) with no pretreatment, frozen storage after oxalic acid treatment without blanching (FON) and with blanching (FOB) were examined. Water binding capacity, swelling power, solubility, and viscosity of the starch produced from RNT, FNT, and FON were similar to those of the starch produced from control (CON). FOB showed significant differences in these properties from CON. Textural properties of starch gels prepared from stored chestnuts except FOB also were very similar to those of CON starch gels. The sensory characteristics of steamed FON and FNT were similar to those of steamed CON except in brown color and hardness. Steamed FNT tended to have higher brown color and lower hardness than steamed FON. Steamed RNT showed significant differences in all the sensory properties except in hardness and cooked chestnut flavor. Steamed FOB was significantly higher than steamed CON in water release and off-flavor. Among the storage conditions examined, frozen storage with oxalic acid treatment is recommended for the long-term storage of chestnuts.

• Journal of the Korean Wood Science and Technology
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• 제45권2호
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• pp.232-242
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• 2017

The objective of this study was to examine changes in the porosity and internal structure of wood as it goes through the process of saccharification (extraction of fermentable sugars). This study also examined the use of different drying methods to prepare samples for characterization of internal pores, with particular emphasis on the partially disrupted cell wall. Aspen wood flour samples after dilute acid pretreatment followed by enzymatic hydrolysis were examined for nitrogen adsorption. The resulting isotherms were analyzed for surface area, pore size distribution, and total pore volume. Results showed that freeze drying (with sample pre-freezing) maintains the cell wall structure, allowing for examination of saccharification effects. Acid pretreatment (hemicellulose removal) doubled the surface area and tripled the total volume of pores, which were mostly 10-20 nm wide. Subsequent enzymatic hydrolysis (cellulose removal) caused a 5-fold increase in the surface area and a ~ 11-fold increase in the total volume of pores, which ranged from 5 to 100 nm in width. These results indicate that nitrogen adsorption analysis is a feasible technique to examine the internal pore structure of lignocellulosic residues after saccharification. The information on the pore structure will be useful when considering value-adding options for utilizing the solid waste for biofuel production.

• 상하수도학회지
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• 제16권6호
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• pp.733-740
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• 2002

The effects on dewaterability and settlability of wastewater sludge according to acid and ultrasonic pretreatment which was expected to change ECP (exocellular polymers) compounds in the sludge and bulk solution was investigated. Though ECP which attached to the sludge could stimulate coagulation of sludge particles by bridging effect, but ECP in the bulk solution deteriorated dewaterability and settlability of the sludge on the contrary. That is as the pH of the solution was decreased to 3 gradually by acid treatment, proportionally ECP in the bulk solution was attached to the sludge flocs and resulted in improvement of dewaterability and settlability of the sludge. In case of ultrasonic pretreatment, with proportional to the intensity and duration of ultrasonic application, ECP was detached and extracted from sludge flocs and these phenomena deteriorated dewaterability and settlability. Also because of the increasement of minute sludge particles according to ultrasonic, dewaterability became so much the worse.

• 약학회지
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• 제28권1호
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• pp.53-59
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• 1984

Drug-metabolizing system which has the important role in drug metabolism is localized in smooth endoplasmic reticulum of hepatocytes and is composed of NADPH, NADPH-cytochrome $P_{450}$ reductase, cytochrome $P_{450}$ and others. It is well known that the enzyme system is induced by phenobarbital and methylcholanthrene. Lipid peroxidation is reaction of oxidative deterioration of polyunsaturated lipids. Formation of lipid peroxides in liver microsome has been found to produce degradation of phospholipid, which are major components of microsomal membrane. The relationship between the formation of lipid oxides and the activities of drug-metabolizing enzyme in the liver of rats was reported by several investigators. In this study the effect of riboflavin tetrabutylate, an antioxidant on lipid peroxidation, specially the relationship between lipid peroxidation and drug-metabolizing enzyme system was investigated. In addition the effect of vitamin A derivatives, such as retinoic acid and retinoid on the enzyme was also observed. Results are summarized as followings. 1) The pretretment with riboflavin tetrabutylate inhibited completely the lengthened sleeping time due to $CCl_{4}$ treatment. 2) The increase of TBA value was prevented by the pretreatment with riboflavin tetrabutylate. 3) The pretreatment with riboflavin tetrabutylate also prevented the decrease of drug-metabolizing enzyme caused by $CCl_{4}$. 4) Both retinoic acid and retinoid remarkably decreased the activity of aminopyrine demethylase. Pretreatment of riboflavin tetrabutylate, however, prevented inhibitory effect of retinoic acid on the enzyme activity.

• Journal of Microbiology and Biotechnology
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• 제32권12호
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• pp.1599-1604
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• 2022

Storage stability of freeze-dried lactic acid bacteria is a critical factor for their cost-effectiveness. Long-term storage of lactic acid bacteria enables microbial industry to reduce distribution costs. Herein, we investigated the effect of cold adaptation under supercooling conditions at -5℃ on the viability of Leuconostoc mesenteroides WiKim32 during the freeze-drying process and subsequent storage. Cold adaptation increased the thickness of exopolysaccharides (EPS) and improved the viability of freeze-dried Leu. mesenteroides WiKim32. Compared to non-adapted cells, cold-adapted cells showed a 35.4% increase in EPS thickness under supercooling conditions. The viability of EPS-hydrolyzed cells was lower than that of untreated cells, implying that EPS plays a role in protection during the freeze-drying process. Cold adaptation increased the storage stability of freeze-dried Leu. mesenteroides WiKim32. Fifty-six days after storage, the highest viability (71.3%) was achieved with cold adaptation at -5℃. When EPS-containing broth was added prior to the freeze-drying process, the viability further increased to 82.7%. These results imply that cold adaptation by supercooling pretreatment would be a good strategy for the long-term storage of Leu. mesenteroides WiKim32.

• Journal of Microbiology and Biotechnology
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• 제24권5호
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• pp.629-638
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• 2014

This study describes an alternative mixed culture fermentation technology to anaerobically convert lignocellulosic biomass into butyric acid, a valuable product with wide application, without supplementary cellulolytic enzymes. Rice straw was soaked in 1% NaOH solution to increase digestibility. Among the tested pretreatment conditions, soaking rice straw at $50^{\circ}C$ for 72 h removed ~66% of the lignin, but retained ~84% of the cellulose and ~71% of the hemicellulose. By using an undefined cellulose-degrading butyrate-producing microbial community as butyric acid producer in batch fermentation, about 6 g/l of butyric acid was produced from the pretreated rice straw, which accounted for ~76% of the total volatile fatty acids. In the repeated-batch operation, the butyric acid production declined batch by batch, which was most possibly caused by the shift of microbial community structure monitored by denaturing gradient gel electrophoresis. In this study, batch operation was observed to be more suitable for butyric acid production.

• Journal of Plant Biotechnology
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• 제32권1호
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• pp.37-44
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• 2005

고추의 나출 소포자로부터 배를 유기하는데 최적인 조건을 확립하기 위하여 micro-blender를 사용하여 소포자들을 나출한 후 NLN 배지에 배양하였으며 $32^{\circ}C$의 고온처리 기간, 전처리 배지내 2-hydroxynicotinic acid의 첨가, 그리고 약과 소포자의 공동전처리가 소포자배의 발생에 미치는 영향을 조사하였다. 나출 소포자들을 기아배지에서 고온처리 한 후 NLN 배지에 배양하였을 때 다수의 배가 발생하였다. 배양 3주 후부터 구형 및 어뢰형배가 관찰되었는데 이때 배의 발생은 비동조적으로 일어났다. 배양4주가 되면 구형과 어뢰형배 이외에 자엽배들이 발생하였다. 발생한 배들 중자엽배늘은 $2\%$ sucrose가 첨가되고 생장조절물질은 첨가되지 않은 B5 고체배지로 옮겼을 때 정상인 유식물들로 발달하였다. 고온처리 기간이 $1\~2$일로 짧은 경우 소포자배의 발생은 높았으나 대부분이 발달초기의 구형 또는 심장형배이었으며 자엽배의 발생은 매우 드물었다. 고온처리 3일 이상에서는 배의 발생은 크게 감소하였으나 자엽배가 다수 발생하였다. Inducer chemical로 알려진 2-hydroxynicotinic acid를 약전처리배지에 첨가하였을 때 배의 발생은 다소 높았으나 발달은 오히려 억제되어 대부분이 구형 또는 심장형이었다. 소포자 전처리시 약을 첨가한 경우 배의 발생이나 발달 모두 억제되었다. 본 연구결과 고추의 나출 소포자로부터 다수의 배를 획득하였고 식물체를 재분화 시키는데 처음으로 성공하였다. 이와 같은 소포자 배양시스템은 앞으로 더 많은 배를 생산할 수 있는 배양조건이 확립되어야 하지만 homozygous한 배가 반수체의 생산 뿐만아니라 형질 전환과 열성 또는 우성의 돌연변이체 선발에 매우 유용하게 이용될 수 있을 것이다. 비해 $ 0.27\~0.79\;\cal{mg/g}$ F.W.가 높았으며 환기횟수 $0.1 h^{-1}$ 처리구는 광도의 증가에 따른 효과가 나타나지 않았으나 환기횟수 $0.1 h^{-1}$ 처리구는 높은 광도에서 감소하였다. 환기횟수 $4.9 h^{-1}$는 $0.1 h^{-1}$에 비해 잎의 공변세포가 크고 주변 부세포가 잘 발달되어 있었다. 특히 PPF $99\;{\mu}mol\;m^{-2}s^{-1}$에서 환기횟수 $0.1 h^{-1}$는 부세포의 발달이 미흡하고 기공이 많이 열려 있는 상태인 반면 환기횟수 $4.9 h^{-1}$는 부세포가 잘 발달된 잎을 지니고 있었다.:PR30, KB50:PR50, PR100:KB0 처리구의 $1m^2$ 당 개체 수는 각각 16,600개, 6,700개, 4,900개, 3,300개, 12,400개였으며 총직립경 수는 각각 33,200개, 22,800개, 18,000개, 15,000개, 62,000개였다. 개체 수는 KB100:PR0처리구가 가장 높았고, 다음은 PR100:KB0처리구였으며 혼합처리구의 경우는 Kentucky bluegrass 혼합비 율이 높을수록 높았다. 총직립경 수는 PR100:KB0 처리구가 KB100:PR0 처리구보다 오히려 높았으며 혼합 처리구의 경우는 개체수와 비슷한 경향을 보였다. 혼합처리구의 경우 초종별 개체수의 비율은 KB80:PR20는 87:13, KB70:PR30는 78:22, KB50:PR50은 48:52의 비율로 나타났다. 조성시기의 기상과 피복율과의 상관관계 2001년 가을과 2002년 봄의 일일평균기온을 비교하여 보면 가을(9월, 10월, 11월) 3개월간의 일일평균기온은

• Journal of the Korean Wood Science and Technology
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• 제39권1호
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• pp.75-85
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• 2011

이 연구에서는 백합나무($Liriodendron$ $tulipifera$)를 옥살산으로 전처리한 시료로부터 에탄올 생산 가능성을 조사하고, response surface methodology (RSM)를 도입하여 전처리 조건을 분석하고자 한다. 산농도, 전처리 시간, 반응 온도를 조절하여 $2^3$ factorial central composite experimental design을 바탕으로 각기 다른 15가지의 전처리 조건에서 시험하였다(central point에서 2반복). 전처리 후 고체 시료는 발효 균주인 $Pichia$ $stipitis$를 사용하여 동시당화발효로 에탄올 생산에 이용되었으며, 각각의 시료에서의 72시간에서의 에탄올 생산량(y,g/${\ell}$)이 최대값으로, 종속변수로써 RSM에 적용되었다. $180^{\circ}C$에서 40분간 0.013 g/g의 옥살산으로 처리한 시료가 가장 많은 양의 에탄올(9.7 g/${\ell}$)을 생산하였으며, response surface methodology 분석에 따르면, 전처리 조건에서 온도 인자가 ethanol에 가장 큰 영향을 미치는 것으로 제시되었으며, 결과는 수식화되어 나타내었다.