• Mycobiology
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• 제42권3호
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• pp.249-255
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• 2014

We evaluated a more practical and cost-effective immobilization carriers for ethanol production using the yeast Saccharomyces cerevisiae. Three candidate materials-rice hull, rice straw, and sawdust-were tested for their cell-adsorption capacity and operational durability. Derivatizations of rice hull, rice straw, and sawdust with the optimal concentration of 0.5 M of 2-(diethylamino)ethyl chloride hydrochloride (DEAE HCl) resulted in > 95% adsorption of the initial yeast cells at 2 hr for DEAE-rice hull and DEAE-sawdust and in only approximately 80% adsorption for DEAE-rice straw. In addition, DEAE-sawdust was found to be a more practical carrier for immobilizing yeast cells in terms of operational durability in shaking flask cultures with two different speeds of 60 and 150 rpm. Furthermore, the biosorption isotherms of DEAE-rice hull, -rice straw, and -sawdust for yeast cells revealed that the $Q_{max}$ of DEAE-sawdust (82.6 mg/g) was greater than that of DEAE-rice hull and DEAE-rice straw. During the 404-hr of continuous column reactor operation using yeast cells immobilized on DEAE-sawdust, no serious detachment of the yeast cells from the DEAE-sawdust was recorded. Ethanol yield of approximately 3.04 g/L was produced steadily, and glucose was completely converted to ethanol at a yield of 0.375 g-ethanol/g-glucose (73.4% of the theoretical value). Thus, sawdust is a promising practical immobilization carrier for ethanol production, with significance in the production of bioethanol as a biofuel.

• 분석과학
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• 제13권5호
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• pp.636-645
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• 2000

본 연구에서는 GC/MS를 이용하여 수질시료로부터 7종의 유기주석화합물을 분석하는 방법을 연구하였다. Hydrogenation과 ethylation의 반응시의 pH, 반응시간, 반응시약의 농도 등을 변화시켜 최적 반응조건을 조사하였다. n-Hexane을 용매로 사용한 액체-액체 추출 후 hydrogenation에 의한 유기주석염화물의 추출 회수율은 61-112% 범위로 나타났다. 물시료에서 ethylation한 후 n-hexane으로 추출한 경우의 추출 회수율이 74-113% 범위로 나타나 hydrogenation의 경우보다 높은 추출율을 보였다. 또한 ethylation후 styrene-divinylbenzene (SDB) 재질의 disk형의 고체상을 사용하고 추출 용매로 methylene chloride를 사용한 경우 61-97% 범위의 회수율을 나타냈다. Hydrogenation과 ethylation에 의한 검출한계는 각각 0.05-0.5 ng/ml와 0.02-0.05 ng/ml로 나타났다.

• Bulletin of the Korean Chemical Society
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• 제30권7호
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• pp.1497-1504
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• 2009

GC/MS analysis of catecholamines (CAs) in biological sample may produce poor reproducible quantitaion when chemical derivatization is used as the technique to form a volatile derivative. Significant quantities of the side products can be formed from CAs with primary amine during the derivatization reaction under un-optimized conditions. We have tested various chemical derivatization techniques in an attempt to find an optimum derivatization method that will reduce side product formation, enable to separate several catecholamine derivatives in GC chromatogram, and obtain significant improvement of detection sensitivity in GC/MS analysis. Whereas several derivatization techniques such as trimethylsilylation (TMS), trifluoroacylation (TFA), and two step derivatization methods were active, selective derivatization to form O-TMS, N-heptafluorobutylacyl (HFBA) derivative using N-methyl-N-(trimethylsilyl)-trifluoroacetamide (MSTFA) and N-methyl-bis(heptafluorobutyramide) (MBHFBA) reagents was found to be the most effective method. Moreover, this derivative formed by selective derivatization could provide sufficient sensitivity and peak separation as well as produce higher mass ion as base peak to use selected ion in SIM mode. Calibration curves based on the use of an isotopically labeled internal standard show good linearity over the range assayed, 1 ~ 5000 ng/mL, with correlation coefficients of > 0.996. The detection limits of the method ranged from 0.2 to 5.0 ppb for the different CAs studied. The developed method will be applied to the analysis of various CAs in biological sample, combined with appropriate sample pretreatment.

• 분석과학
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• 제6권1호
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• pp.9-19
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• 1993

최근 합성계면활성제의 사용 증가에 따른 수질오염의 우려로 인하여 천연 유지비누의 사용이 증가되고 있는 실정이다. 그러나 하천의 자정용량을 초과하는 오염물질의 유입이 수질 오염을 유발하는 원인이 되므로 과도한 사용량의 증가 역시 환경에 부하를 준다. 현재까지 비누 지방산의 생분해 측정방법이 공정화되어 있지 않아 비누에 의한 수질오염도를 파악하기 어려웠다. 따라서 본 연구에서 새로이 측정방법을 고안하였고 환경 중 비누의 생분해도를 측정, 평가하였다. 본 연구의 내용 및 결과는 다음과 같다. 비누 중의 지방산염들은 비극성, 비양자성 용매하에서 crown ether를 촉매로 하여 p-BPB(p-bromophenacyl bromide)와 고체-액체 상전이 반응으로 유도체화시켰고 역상 고성능 액체크로마토그래피에 의해서 분리시켰다. 검출한계는 탄소사슬 길이에 따라 대략 10~50ng이었고, EDTA 첨가에 의한 유도체화 반응은 칼슘염 뿐만 아니라 다른 금속염에도 적용시킬 수 있었다. Yeast extract 존재 유무에 따라 지방산 유도체화 반응의 회수율은 각각 $95.4{\pm}1.2$,$85.2{\pm}2.4%$였다. 본 분석법은 진탕배양법과 같은 인위적인 조건 뿐만 아니라 자연계에 존재하는 지방산염의 생분해도 측정에 적용하였다.