• 한국환경과학회지
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• 제23권5호
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• pp.943-962
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• 2014

Industrial gas drying, dilute gas mixtures purification, air fractionation, hydrogen production from steam reformers and petroleum refinery off-gases, etc are conducted by using adsorptive separation technology. The pressure swing adsorption (PSA) has certain advantages over the other methods, such as absorption and membrane, that are a low energy requirement and cost-effectiveness. A key component of PSA systems is adsorbents that should be highly selective to a gas being separated from its mixture streams and have isotherms suitable for the operation principle. The six standard types of isotherms have been examined in this review, and among them the best behavior in the adsorption of $CO_2$ as a function of pressure was proposed in aspects of maximizing a working capacity upon excursion between adsorption and desorption cycles. Zeolites and molecular sieves are historically typical adsorbents for such PSA applications in gas and related industries, and their physicochemical features, e.g., framework, channel structure, pore size, Si-to-Al ratio (SAR), and specific surface area, are strongly associated with the extent of $CO_2$ adsorption at given conditions and those points have been extensively described with literature data. A great body of data of $CO_2$ adsorption on the nanoporous zeolitic materials have been collected according to pressure ranges adsorbed, and these isotherms have been discussed to get an insight into a better $CO_2$ adsorbent for PSA processes.

• Journal of Microbiology and Biotechnology
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• 제8권4호
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• pp.353-360
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• 1998

A bacterial strain PN33 producing large amounts of extracellular pectin lyase (PNL, EC 4.2.2.10) was isolated from soil. The isolated bacterium was identified as a strain of Bacillus sp. Production of PNL by the strain was induced only by pectins, with a higher degree of esterification, which had been added to the culture medium as a sole carbon source. The optimal medium for PNL production was determined to consist of 10 g pectin, 2 g yeast extract, 4 g $K_2HPO_4{\cdot}3H_2O$, 0.6 g $MgSO_4$, and 0.11 g $CaCl_2$ per liter (pH 7.0). The PNL activity in the culture supernatant reached the highest level of 132 mU/ml after 32 h cultivation at $37^{\circ}C$ in the optimal medium. The PNL produced was purified to homogeneity by ammonium sulfate fractionation (50~80%), and cation exchange and size exclusion chromatographies. The molecular mass of the enzyme was estimated to be approximately 52 kDa by SDS-PAGE. Almost the same mass was determined by nondenaturing PAGE, indicating that the functional enzyme had a monomeric structure. As expected, the PNL exhibited higher activities on the highly esterified pectins whereas it gave no detectable activity on polygalacturonic acid. The enzyme showed the highest activity at the acidic pH of 6.0, exceptional for a bacterial PNL. Maximum activity was measured at $40^{\circ}C$, although the stability f the purified enzyme was poor at this temperature. alcium (1 mM) was found to activate the PNL activity by $50\%$, and also remarkably increased the thermal stability f the enzyme. Phenylmethylsulfonylfluoride (PMSF) and iethylpyrocarbonate (DEPC) inhibited the PNL activity lmost completely at the concentration of 5 mM. This result ndicates that some serine and histidine residues of the nzyme may play an essential role for catalytic function of he enzyme.

• ALGAE
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• 제22권3호
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• pp.247-252
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• 2007

Crude fucoidan was extracted from the sporophyll of Korean Undaria pinnatifida collected at a coastal area ofWando, Korea, mainly by dilute acid extraction, ethanol precipitation, CaCU Precipitation, with an yield of approxi-mately 3.9% in mass. It was further purified by DEAE-cellulose column chromatography and its chemical composi-don and in vitro anticoagulant activity was determined. The average molecular mass of the purified fucoidan wasestimated about 2.1 x 103 kDa by size-fractionation HPLC and it consisted of neutral sugar (52.34% in mass), uronicacid (26.2%), and sulfate esters (7.4%). From the HPAEC-PAD analysis, the monosaccharide composition of thepurified fucoidan was shown to be fucose, galactose, xylose, and mannose, with a molar ratio of 1, 0.2, 0.02, 0.15,respectively, demonstrating that major monosacd-iande was fucose (72.3% in mol percentage) and other sugars,xylose (1.5%), galactose (14.6%), and mannose (10.9%) were present as minor component. The results suggested thatthis fucoidan is a sulfated, U-type fucoidan. The activated partial thrombloplastin time (APTT) assay of the purifiedfucoidan showed that the purified fucoidan elicited anticoagulant activity in a dose-dependent manner. Five jUg ofsporophyll fucoidan delayed the blood clotting time up to 5 times than untreated control and also up to 1.5 timesthan the same amount of the commercial fucoidan, respectively. Although it is preliminary, these results suggestthat the fucoidan of Korean Undaria vinnatifida sporophyll would be promising candidates for the development ofan anticoaeulant.

• 미생물학회지
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• 제26권3호
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• pp.197-206
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• 1988

Klebsiella pneumoniae의 세포외막으로부터 2-furaldehyde를 2-furoic acid로 산화시키는 2-furaldehyde dehydrogenase를 분리하여 그 특성을 조사하였다. 이 효소는 $\beta$-$NAD^{+}$를 특이적으로 요구하였다. 분리과정중의 효소활성도는 2-furaldehyde를 기질로 사용하고 $\beta$-$NAD^{+}$를 조효소로 사용하면서 high performance liquid chromatography에 의해 측정 되었다. 세포외막은 Percoll의 밀도흉배에 의한 초원심분리방법과 $Mg^{2+}$, Triton X-100으로 용해시킨 후, 초원심분리시키는 방법으로 수집되었다. 세포외막단백질은 EDTA와 lysozyme을 처리함으로서 얻어졌고, 효소는 QAE-Sephadex Q-504 S Sephadex G-100-을 사용하면서 column chromatography 방법에 의해 분리되었다. 본 효소는 $85^{\circ}C$, PH9.5, 그리고 1.5% (vol/vol) Triton X-100의 존재하에서 최대활성을 보여주었다. 효소의 분자량은 nondenaturing polyacrylamide gel e electrophoresis의 결과, 88, 000.으로 추정되었고, 2-furaldehyde에 대한 효소의 Km값은 4.72 mM 이였다.

• Ocean and Polar Research
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• 제38권2호
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• pp.129-137
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• 2016

This study aimed to isolate and characterize sulfated polysaccharides (SPs) from Iridaea cordata and evaluate their anticancer activity. SPs of the Antarctic red seaweed were obtained by $CaCl_2$ (SP1) and ethanol precipitations (SP2) following diluted acid extraction at room temperature. Yields of SP1 and SP2 were approximately 14% and 23%, respectively, of the dry weight of red seaweed. The average molecular mass of the SP1 and SP2 was estimated about $1.84{\times}10^3$ and $1.42{\times}10^3kDa$, respectively, by size-fractionation High-Performance Liquid Chromatography (HPLC). From the High-Performance Anion-Exchange Chromatography-Pulsed Amperometric Detection (HPAEC-PAD) analysis, the main monosaccharide was galactose with glucose and fucose as minor components. The sulfate content of SP2 (40.4%) was slightly higher than that of SP1 (33.8%). The FT-IR spectra also showed characteristic band of carrageenan-like sulfated polysaccharides. Taken together the SPs are thought to be carrageenan-like sulfated galactan. The polysaccharides (SPs) from I. cordata exhibited weak antitumor activity against PC-3 (prostate cancer), HeLa (cervical cancer), and HT-29 (human colon adenocarcinoma). To our knowledge, this is the first data on biological activity of the Antarctic red seaweed I. cordata.

• Archives of Pharmacal Research
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• 제18권1호
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• pp.12-17
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• 1995

It is essential to clone the preptide transporter in order to obtain better understanding of its molecular structure, regulation, and substrate specificity. Characteristics of an endogenous peptide transporter in oocytes were studied along with expression of an exogenous protor/peptide cotransporter from rabbit intestine. And further efforts toward cloning the transporter were performed. The presence of an endogenous peptide transporter was detected in Xenopus laevis oocytes by measuring the uptake of $0.25/{mu}M(10{\;}{\mu}Ci/ml)[^3H]$-glycylsarcosine (Gly-Sar) at pH 5.5 with or without inhibitors. Yptake of Gly-Sae in oocytes was significantly inhibited by $25{\mu}M$ glycine nd sarcosine. This result suggests that a selective transporter is involved in the endogneous uptake of dipeptides. Collagenase treatment of oocytes used to strip oocytes from ovarian follicles did not affect the Gly-Sar uptake. Changing pH from 5.5 to 7.5 did not affect the Gly-Sae uptake significantly, suggesting no depedence of the endogenous transporter on a transmembrane proton gradient. An exogenous $H^+/pep-tide$ contransported was expressed after microinjection of polyadenylated messenger ribonucleic acid $[poly(A)^+ -mRNA]$ obtained from rabbit small intestine. The Gly-Sar uptake in mRNA-injected oocytes was 9 times thigher than that in water-injected oocyltes. Thus, frog occytes can be utilized fro expression cloning of the genes encoding intestinal $H^+$peptide contransporters. Size fractionation of mRNA was successfully obtained using this technique.

• 대한수의학회지
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• 제11권2호
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• pp.123-136
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• 1971

이 실험(實驗)은 계혈청(鷄血淸)에 들어 있는 뇌염(腦炎)바이러스에 대한 비특이억제물질(非特異抑制物質)(NSI)의 성상(性狀)과 이의 Acetone-ether와 Kaolin 처리(處理)에 의한 NSI의 제거효력(除去效力)등을 Gel filtration 및 Zonal Centrifugation technique를 이용하여 시험 하였다. 그 결과(結果) (1) 계혈청(鷄血淸)에 들어 있는 비특이 억제물질은 Group A arbovirus 보다 Group B arbovirus에 대하여 더 예민하였다. (2) 연령(年齡)에 의한 NSI의 역가(力價)차이는 없었다. (3) NSI를 제거(除去)하기 위한 Acetone-ether 및 Kaolin 처리는 그 효력면에서 차이가 없었다. (4) 계혈청(鷄血淸)을 일정한 온도(溫度)로 가열(加熱)하면 NSI의 역가(力價)가 상승(上昇) 하였다. (5) NSI의 성분(成分)은 Gel filtraction에서 주로 첫 Peak (IgM)에 있었고, Zonal Centrifugation에서는 원심관의 상층(上層)에 있는 것으로 보아, 이것은 분자량(分子量)은 크고 Density는 낮은 지질단백(脂質蛋白)으로 생각된다. (6) 거위 적혈구에 대한 응집소(NA)는 acetone-ether 처리에 의하여 부분적(部分的)으로 파괴 되었으나 Kaolin 처리에서는 그렇지 못하였고, 10% 거위혈구액으로써 완전 제거할 수 있었다. (7) NA는 Gel filtration 및 Zonal Centrifugation에서 첫 peak (IgM)에 나타났다.