• 한국연초학회지
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• 제30권1호
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• pp.25-32
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• 2008

In this study, we compared three different pretreatment methods, such as block digestion, microwave digestion and solvent injection, coupled with Octopole Reaction System(ORS)-ICP-MS was used for the quantification of heavy metals in mainstream smoke of 2R4F reference cigarette, and then evaluated those efficiencies in the recovery, repeatability and reproducibility. In all methods, volatile heavy metals, As, showed the highest CV value, and Cd showed the lowest one. However, the solvent injection method showed the most stable recovery rate and CV value of 2.36 %. This method showed also advantages in time-consuming and compatibility with ICP-MS system. This results demonstrate that solvent injection method can be recommended as a superior pretreatment procedure to be able to reduce contaminants and spectral interference as well as loss of the elements interested.

• KSBB Journal
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• 제15권4호
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• pp.411-413
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• 2000

본 연구에서는 Lactobacillus crispatus KLB46의 genomic DNA를 빠르고, 간단하게 소량 (3 mL)의 배양액에서부터 추출하는 방법을 확립하였다. 이 방법을 이용하여 L. crispatus KLB46로부터 total genomic DNA를 분리한후 peR과 제한효 소처리를 하여 전기영동으로 확인하였다. 질의 정상세균총을 이루고 병원성균의 증식을 억제하는 그램양성균인 L. crispatus KLB46의 genomic DNA의 신속한 추출방법은 이 균주의 유 전공학연구에 유용하게 사용될 수 있을 것으로 기대된다.

• 한국식품영양과학회지
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• 제27권6호
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• pp.1160-1165
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• 1998

When total cellular DNA was isolated from Porphyra tenera by ultracentrifugation on Hoechst dye/CsCl gradients method, plasmid like DNA's were concentrated at the upper band which were characterized with a A＋T rich organelle DNA's in the CsCl gradients. Based on their electrophoretic migration in different concentration of agarose gel, buffer system, and electric power etc. and the results of restriction digestion, the plasmid like DNA's were concluded to have circular conformation. This is the first report of putative circular plasmid DNA from the P. tenera, which is a autonomously replicating plasmid existing with a high copy number plasmid in the cell. The minimum size of this plasmid estimated by restriction endonuclease digestion was appeared to be 2.5kb in size.

• BMB Reports
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• 제29권2호
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• pp.122-126
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• 1996

A series of oligonucleotides were synthesized by automatic DNA synthesizer. The purity of crude products was checked and their molecular weights determined by matrix assisted laser desorption ionization mass spectrometry (MALDI-MS) with an accuracy of better than 0.05% deviation even without using an internal standard. This mass determining technology in combination with partial digestion of oligonucleotides by 5'- and 3'-exonuclease provides a straightforward and simple method to obtain sequence information of oligonucleotides. The extension of this technology to the sequencing of modified oligonucleotides and genomic DNA and RNA might become possible.

• Journal of Microbiology and Biotechnology
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• 제17권11호
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• pp.1904-1907
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• 2007

The aim of this study was to develop a new fermentation method in order to improve the digestion of soybean protein, and to promote normal fermentation of soybean. A proximate composition, such as moisture, pH, and reducing sugar, of fermented soybeans by the new fermentation was similar to those of controls. Neutral protease activity, the most important factor for fermented soybean products, was the highest, having about 636 Dig at 54 h fermentation. The content of total free amino acid was almost 3-18 times higher than controls. The three-step fermented soybeans can be used as a functional food ingredient for human consumption, with higher protein digestibility.

• Mycobiology
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• 제37권3호
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• pp.240-242
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• 2009

An improved procedure for preparing PCR cloning vectors was developed. This procedure includes the incorporation of adapters to create XcmI restriction enzyme sites in pBluescript II SK(+) vectors, digestion with XcmI followed by further digestion of the small fragment produced by XcmI digestion with additional enzymes, and purification with PCR purification kits. Using this procedure, PCR cloning vectors with high ligation efficiencies and low blue or false-positive colonies were obtained.

• Environmental Engineering Research
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• 제11권3호
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• pp.143-148
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• 2006

The ultrasonics is a new technology in waste activated sludge(WAS) treatment. Ultrasonic treatment is well known method for the break up of microbial cells to extract out a variety of intercellular materials inside microorganism cell. This study was done to investigate the effects of the ultrasonic frequency and power on disruption of biosolids in WAS and to examine the effect on methane production of WAS treated by ultrasonics. Biosolids disruption with ultrasound is more effective at ultrasonic frequency of 40 kHz and power of 0.3 watt/mL. In the digestion with WAS pretreated by sonication time for 10 minute at 40 kHz and 0.3 watt/mL, the total quantity of generated methane increased by 75%, as compared with experimental control(non-treatment).

• 산업기술연구
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• 제39권1호
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• pp.21-25
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• 2019

This work experimentally determined the effect of microaerobic condition on anaerobic digestion of thickened waste activated sludge in semi-continuous mesophilic digesters at hydraulic retention time of 20 days. The concentration of hydrogen sulfide was $7{\pm}2ppm$ at the microaerobic condition and $14{\pm}2ppm$ at the anaerobic condition. Removal efficiency of volatile solid was not significantly different between microaerobic ($40{\pm}8%$) and anaerobic ($38{\pm}8%$) conditions. There was no important difference between microaerobic ($1,352{\pm}98ml/d$) and anaerobic ($1,362{\pm}104ml/d$) conditions in the biogas production, either. Therefore, it could be concluded that the application of the microaerobic condition was an efficient method of the hydrogen sulfide removal from the biogas.

• 환경위생공학
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• 제16권1호
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• pp.91-101
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• 2001

In order to propose a optimum method increasing accuracy and reproducibility in analysis of urine lead levels, we compared matrix modifier addition method and microwave digestion method. The results were as follows ; 1. Where the concentration of $Pd(NO_3)_2$(matrix modifier) was $50mg/{\ell}$, and ashing temperature was $900^{\circ}C$, the results were optimum. In case of matrix modifier addition method, the average coefficient of variation (CV) of normal man was 24.1%, and lead worker was 7.9%. The average urine lead levels of standard were $10.42\mu{g}/{\ell}$ and $19.89\mu{g}/{\ell}$ , the accuracies compared to reference values were 97.0% and 92.6%, respectively. 2. Microwave digestion temperature($160~180^{\circ}C$), time(15~25min) and the ratio of urine/ashing acid(1:1~4:1) did not significantly affect lead absorbance and background absorbance. Therefore we set up a optimum analytical conditions as follows: temperature, $160^{\circ}C$; time, 15min; the ratio of urine/ashing acid, 4:1. after samples were digested by the above analytical conditions, lead absorbance and background absorbance was measured at $450^{\circ}C$ as ashing temperature. The average coefficient of variation (CV) of normal man was 12.4%, and lead worker was 6.2%. The average urine lead levels of standard urine were $10.66\mu{g}/{\ell}$ and $23.31\mu{g}/{\ell}$, the accuracies compared to reference values were 99.3% and 103.9%, respectively. From the results, we suggest that microwave digestion method is a more favorable method than matrix modifier addition method because of easiness to reduce organic matter, possibility to analysis at low temperature and accuracy.

• Food Science and Biotechnology
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• 제16권3호
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• pp.493-495
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• 2007

In this study, the acrylamide contents of foods were estimated via liquid chromatography (LC)/mass spectrometry (MS)/MS after the food matrix constituents had been degraded with digestive enzymes (i.e., pepsin and pancreatin) and extracted with water. The quantities of acrylamide released from samples of cereal, potato chips, peanuts, and coffee were $62{\pm}5.1,\;970,\;106{\pm}20$, and 890 ppb, respectively. No acrylamide was detected in samples of soybean curd (tofu), fish cake, and ham. Compared to the amounts of acrylamide detected after extraction with water only, we noted no significant differences in the soybean curd, fish cake, potato chip, ham, and coffee samples. However, the quantities of acrylamide released from the cereal and peanut samples were approximately 2-fold larger following pretreatment with the digestive enzymes. This study presents a new in vitro enzymatic digestion method which allows for a more accurate estimation of the acrylamide contents of foods.