• Journal of Microbiology and Biotechnology
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• 제12권4호
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• pp.535-543
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• 2002

Although the generic implementation of aqueous two-phase systems (ATPS) processes for the recovery of biological products has been exploited for several years, this has not resulted in a wide adoption of the technique. The main reasons involve the poor understanding of the mechanism governing phase formation and the behavior of solute partitioning in ATPS processes, the cost of phase forming polymers, and the necessary extended time to optimize the technique. In this review paper, some of the practical disadvantages attributed to ATPS are addressed. The practical approach exploited to design ATPS processes, the application to achieve process integration, the extended use for the recovery of high-value products, and the recent development of new low-cost ATPS, are discussed. It is proposed that the trend of the practical application of ATPS processes for the recovery of biological products will involve the purification of new high-value bioparticulate products with medical applications. Such a trend will give new impetus to the technique, and will draw attention from industries needing to develop new, and improve existing, commercial processes.

• Journal of Applied Biological Chemistry
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• 제55권3호
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• pp.149-156
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• 2012

The effects of solvent type and concentration, solid/liquid ratio, extraction time and repeated extraction on recovery of keratinase from solid-state fermentation (SSF) of chicken feather by a local Streptomyces sp. NRC 13S were investigated in order to establish the experimental conditions for keratinase yield. Among solvents tested, 0.5% (v/v) glycerol was the best. Box-Behnken design was used to investigate the effect of relevant variables on keratinase recovery. The factors investigated were solid/liquid ratio (1:1.66-1:6.66 g/mL), glycerol concentration (0.5-5% v/v) and repeated extraction (1-5 cycle). The results showed that the maximum recovery of keratinase (6933.3 U/gfs) was obtained using 0.5 (v/v) glycerol as extracting solvent, in a solid/liquid ratio of 1:5 and three extraction cycles.

• Biotechnology and Bioprocess Engineering:BBE
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• 제6권6호
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• pp.419-425
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• 2001

A dense pellicular solid matrix has been fabricated by coating 4% agarose gel on to dense zironia-silica(ZS) spheres by watr-in-oil emulsification . The agarose evenly laminated the ZS bead to a depth of 30㎛, and the resultin gpellicular assembly was characterised by densities up to 2.39g/mL and a mean particle dimeter of 136 ㎛. In comparative fluidisation tests, the pellicular solid phase exhibited a two-fold greater flow velocity than commercial benchmark ad-sorbents necessary to achieve common values of bed expansion. Furthermore, the perlicular parti-cles were characterised by improved qualities of chromatographic behaviour, particularly with re-spect to a three-fold increase in the apparent effective diffusivity of lysozyme within a pellicular assembly modified with Cibacron Blue 3GA. The properties of rapid protein adsorption/desorp-tion were attributed to the physical design and pellicular deployment of the reactive surface in the solid phase. When combined with enhanced feedstock throughput, such practical advantages recommend the pellicular assembly as a base matrix for the selective recovery of protein products from complex, particulate feedstocks(whole fermentation broths, cell disruptates and biological extracts).

• 한국환경농학회지
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• 제42권3호
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• pp.220-230
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• 2023

Imidacloprid is a neonicotinoid insecticide widely used for insect control in a variety of crops. The evaluation of imidacloprid total residues in animal feeds derived from crop by-products is required to ensure the safety of livestock products. We performed simultaneous LC/MS/MS analyses of imidacloprid and its metabolites in five different livestock products including beef, pork, chicken, milk and egg from domestic markets. The methods for sample preparation and instrumental analysis were established by modifying QuEChERS method to meet the Codex guidelines. The methods generated 0.0035 mg/kg of the limit of determination (LOD), 0.01 mg/kg of the limit of quantitation (LOQ) and standard calibration linearity with >0.983 of the coefficients of determination (R²). The methods exhibited the recovery values of imidacloprid and its metabolites ranging from 65.66 to 119.27% without any interference between matrices. Imidacloprid total residues in the livestock products were found as values lower than the LOQ and maximum residue limits (MRLs). This study suggests that the methods are successfully applicable for the safety evaluation of imidacloprid total residues in livestock products from domestic markets.

• 한국환경농학회지
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• 제41권3호
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• pp.206-216
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• 2022

BACKGROUND: Dithiocarbamate fungicide propineb can be analyzed quantitatively by derivatization reaction followed by HPLC/UVD, which has high reproducibility and stability. However, the presence of high protein in soybeans and peas affects the derivatization process resulting in extremely low recoveries. Therefore, this study was conducted to improve the analytical method for analysis of propineb in soybeans and peas by applying a deproteinization process using chloroform-gel method. METHODS AND RESULTS: The deproteinization process was carried out up to 6 times for soybeans and 5 times for peas using 50 mL chloroform. After 4 times of deproteinization process followed by a derivatization reaction with methyl iodide, the recovery yields of propineb in both pulses were >90%. However, the recovery yield tended to decrease when the deproteinization process was performed more than 5 times. The method limit of quantification (LOQ) was 0.04 mg/L. The recovery conducted in triplicate at 10 times and 50 times of the LOQ ranged from 87.2 to 95.0 % with a coefficient of variation <10%. CONCLUSION(S): This study confirmed that 4 times of deproteinization process using the chloroform-gel method was effective when derivatizing and analyzing dithiocarbamate fungicides in pulses with high protein content. However, depending on the initial protein content present in the pulses, there was a difference in the recovery: the lower the protein content, the higher the recovery rate of propineb. It is expected that the method proposed in this study could be applied to remove high content of protein as analytical interference substance from agricultural samples.

• 한국토양비료학회지
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• 제44권3호
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• pp.387-393
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• 2011

본 연구는 환원증류법을 사용하여 축사, 매립지, 시설재배지 등 높은 수준의 질산태 질소로 오염된 토양의 질산태질소 함량을 정확히 측정하는데 있어서, Devarda's alloy 의 입자 크기가 질산태 질소의 회수율에 미치는 효과와 Devarda's alloy의 처리량과 환원된 질산태 질소의 양과의 상관관계, 고농도의 질산태 질소를 함유한 토양 추출액의 정확한 분석을 위한 적절한 접근방법을 파악하고자 수행되었다. 본 연구에서 시험된 각 Devarda's alloy는 입자 크기의 분포가 서로 달랐으며, 이는 다소 높은 질산태 질소 조건인 1 mg과 2 mg $NO_3$-N에서 서로 다른 질산태 질소 회수율로 반영 되었다. 한편, 고농도의 질산태 질소 조건에서는 모든 Devarda's alloy들이 용액 중 질산태 질소의 함량이 증가할수록 급격히 질산태 질소의 회수율이 감소하는 경향을 보였으나, 시험된 모든 Devarda's alloy들은 예상과 달리, 단위 질량 당 환원된 질산태 질소의 양이 용액중 질산태 질소의 양에 비례하여 감소하는 경향을 보였다. 이상의 연구결과들은 높은 수준의 질산태 질소로 오염된 토양 시료를 안정적으로 분석하기 위해서는 Devarda's alloy의 입자 크기 분포를 감안한 충분한 처리, 그리고 두 수준 이상의 Devarda's alloy를 처리한 후 회수된 질산태 질소량 변화를 살피는 것이 필요하다는 것을 제시한다. 아울러, 본 연구에서 발견된 질산태 질소량의 화학적 비당량성은 앞으로의 연구를 통해 보다 자세히 조사되어야 할 것으로 사료된다.

• 멤브레인
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• 제8권2호
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• pp.69-76
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• 1998

막분리기술은 다른 분리기술에 비해 에너지절약형이며 또 비교적 대량으로 분리를 수행할 수 있다는 장점이 있어 근래 산업 현장에서 많이 이용되고 있다. 특히 mass separating agent를 사용하지 않고, 상변화를 수반하지 않는 순조건에서 실시할 수 있다는 특성으로 인하여 생물물질의 생산 및 회수에 있어서 막분리의 사용이 크게 증가하고 있다. 근래에 들어 막의 재지라 분리 module의 개발 등에 의해 fouling, 농도분극현상 등, 막분리의 근본적 문제점들이 많이 해결되고 있을 뿐 아니라, 기존의 조분리의 영역을 넘어서 정밀분리에로의 발전이 가시화되고 있다. 또한 생물분리기술의 추세인 복합분리와 동시분리의 측면에 있어서도 막분리의 응용성은 우수하여, 향후 생물공학 제품의 생산에 있어 막분리 기술의 역할은 막대할 것으로 사료된다.

• 농약과학회지
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• 제9권3호
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• pp.231-236
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• 2005

본 연구는 생산단계의 딸기에 4가지 살균제(tolclofos-m, folpet, procymidone, triflumizole)를 수확 10일전 안전사용 기준량으로 처리한 후 잔류량을 파악하였고, 이것을 근거로 6 가지 kinetic models(first order, zero order, second order, power function model, elovich model, parabolic model)에 따른 반감기를 비교하였다. 최적의 모델로 판명된 first order kinetic model로부터 구한 반감기를 이용하여 생산단계잔류허용기준(field tolerance)을 설정, 제시하였다. 잔류분석법의 적합성 판단을 위한 회수율 실험에서는 $85.1{\sim}105.0%$ 범위를 보였으며, 4 가지 약제 모두 약제 처리 5일 후 평균 73% 이상 소실되었다. 잔류량과 시간과의 상관관계는 first order kinetic model에서 가장 높은 결정계수값을 보였으며, 이를 이용하여 산출한 반감기로 생산단계 잔류허용기준(안)을 설정하였다. 이와 같은 결과는 최적의 kinetic model로 반감기를 산출해야 한다는 이론적 근거를 제시하는 것이며, 수확 후 또는 유통 중의 잔류허용기준뿐만 아니라 생산단계에서도 허용기준을 마련하여 부적합 품목을 사전에 차단할 수 있는 기준설정의 예로서 안전 농산물 공급과 농가소득에 크게 기여할 수 있는 기초자료가 될 것이라 사료된다.

• 한국환경과학회지
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• 제20권12호
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• pp.1617-1624
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• 2011

Caustic (NaOH) solution is used to remove $H_2S$ from hydrocarbon streams in petroleum refining industry, gradually being, so called, spent sulfidic caustic (SSC) which has high levels of $H_2S$ and alkalinity. Thus, SSC can be used as an electron donor and a buffering agent for autotrophic denitrification. As SSC, however, contains some non-biodegradable organics, air stripping was conducted to remove the non-biodegradable organics. As a result, over 93 % of the non-biodegradable organics was removed within 30 min of aeration. Then, $Na_2S_2O_3{\cdot}5H_2O$, methanol and organic matters, which are produced from a biodiesel production plant, were added to reform the air-stripped SSC and their products being referred to new sulfidic caustics (NSCs) I, II and III, respectively. Thereafter, to investigate the effect of these products on the removal of COD and TN, these products were injected to a biological nitrogen removal (BNR) process, resulting in additional 44 % TN removal without noticeable increase in the effluent COD level. Therefore, it can be said that the BNR process is a promising option to treat NSC as demonstrated in this study whose results can be useful for developing resource recovery technologies.

• Archives of Pharmacal Research
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• 제16권3호
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• pp.213-218
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• 1993

($\pm$)-Higenamine is known as a cardiotonic principle of aconite root (root of Aconitum spp., Ranunculaceae). A simple and sensitive detection method for higenamine was developed by using gas chromatography-mass spectrometry (GC/MS). The recovery of higenamine after extraction and concentration with XAD-2 resin column was around 95% from rat biological fluids such as bile, plasma and urine. The limits of detection of higenamine in these biological fluids were approximately 0.1 ng/ml each. It has well been suggested that tetrahydroisoquinolines possessing catechol moiety such as higenamine should be subjected to the catechol-O-methyl transferase (COMT) activity in vivo. We detected two major peaks of presumed metabolites of higenamine in the total ion chromatogram obtained from the rat urine sample after the oral adminstration of ($\pm$)-higenamine. The scan mass spectrum of one of the metabolties coincided with those obtained from coclaurine $(C_6$-O-methyl higenamine) and those of the other metabolite are suggestive of isococlaurine $(C_7$-O-methyl higenamine).