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Leuconostoc sp.에 의한 Sucrose로부터 Glucose-1-phosphate의 생산
엄익춘,황기철,방원기 한국산업미생물학회 1993 한국미생물·생명공학회지 Vol.21 No.6
Sucrose로부터 glucose-1-phosphate를 생산하기 위하여 sucrose phosphorylase 활성을 지닌 균주를 김치로부터 분리하였으며, 이들 분리 균주로부터 sucrose phosphorylase 비활성이 가장 높은 균주인 JS-05를 선별하였고, Leuconostoc sp.로 동정하였다. Leuconostoc sp. JS-05의 sucrose phosphorylase 비활성은 10 g/ℓ sucrose, 5.0 g/ℓ corn steep liquor 및 2.5 g/ℓ yeast extract를 함유하는 배지를 사용하여, 초기 pH 7.5로 조정한 후 25℃에서 20시간 배양할 때 가장 높았다. 한편, toluene으로 처리된 휴지세포를 이용하여 glucse-1-phosphate를 생산하기 위하여 최적 반응 조건하에서 2시간 반응시킨 결과 68 g/ℓ의 sucrose로부터 21.83 g/ℓ의 glucose-1-phosphate가 생산되었으며, 이는 이론적 glucose-1-phosphate 전환율로는 93.24%에 해당되었다. For the production of glucose-1-phosphate from sucrose, bacteria having sucrose phosphorylase were isolated from Kimchi. Among them, JS-05, newly isolated strain having high activity of sucrose phosphorylase was selected and identified as Leuconostoc sp. The specific activity of sucrose phosphorylase of Leuconostoc sp. JS-05 was the highest when the strain was cultured at 25℃ for 20 hrs in the medium(pH 7.5) containing 10 g sucrose, 5 g corn steep liquor, and 2.5 g yeast extract per liter. Meanwhile, in the glucose-1-phosphate production through the reaction with toluene-treated resting cells. 21.83 g/ℓ of glucose-1-phosphate was produced from 68 g/ℓ of sucrose after incubation of 2 hrs under optimum conditions, which corresponds to 93.24% of theoretical glucose-1-phosphate yield.
고함량 자연방사성물질 우려지역에 대한 지하수 환경 특성 연구
정도환,엄익춘,윤정기,김문수,김영규,김태승,Jeong, Do-Hwan,Eom, Ig-Chun,Yoon, Jeong-Ki,Kim, Moon-Su,Kim, Yeong-Kyoo,Kim, Tae-Seung 한국지하수토양환경학회 2010 지하수토양환경 Vol.15 No.6
Groundwater sampling was performed at 38 wells where they are located in the areas with high uranium and radon (marked as A and B, respectively) concentrations, which were based on the previous research results. In-situ parameters (temperature, pH, EC, Eh, DO) and natural radionuclides (uranium and radon) were analyzed to figure out the characteristics of groundwater environments. In-situ data did not show any relations to natural radionuclide data, which could be caused by groundwater mixing, depths of wells, and geological settings, etc. But the highest radon well presented relatively low temperature value and the highest uranium well presented relatively low pH values The highest uranium concentration ranging $1.14{\sim}188.19{\mu}g/L$ showed in the area of A region consisted of Jurassic two-mica granite. The areas of Jurassic biotite granite and Cretaceous granite in the A region have the uranium concentrations ranging $0.10{\sim}49.78{\mu}g/L$ and $0.36{\sim}3.01{\mu}g/L$, respectively. The uranium values from between wells of community water systems (CWSs) penetrating fractured bed-rock aquifers and personal boreholes settled in shallow aquifers near the wells of CWSs show big differences. It implies that the groundwaters of the two areas have evolved from different water-rock interaction paths that may caused by various types of wells having different aquifers. High radon activities in the area of B region composed of Precambrian gneiss showed ranging from 6,770 to 64,688 pCi/L. Even though the wells are located in the same geological settings, their rodon concentration presented different according to depth and distance.
Comparison of Real Time Nanoparticle Monitoring Instruments in the Workplaces
함승헌,이나루,엄익춘,이병천,Perng-Jy Tsai,이기영,윤충식 한국산업안전보건공단 산업안전보건연구원 2016 Safety and health at work Vol.7 No.4
Background: Relationships among portable scanning mobility particle sizer (P-SMPS), condensation particle counter (CPC), and surface area monitor (SAM), which are different metric measurement devices, were investigated, and two widely used research grade (RG)-SMPSs were compared to harmonize the measurement protocols. Methods: Pearson correlation analysis was performed to compare the relation between P-SMPS, CPC, and SAM and two common RG-SMPS. Results: For laboratory and engineered nanoparticle (ENP) workplaces, correlation among devices showed good relationships. Correlation among devices was fair in unintended nanoparticle (UNP)- emitting workplaces. This is partly explained by the fact that shape of particles was not spherical, although calibration of sampling instruments was performed using spherical particles and the concentration was very high at the UNP workplaces to allow them to aggregate more easily. Chain-like particles were found by scanning electron microscope in UNP workplaces. The CPC or SAM could be used as an alternative instrument instead of SMPS at the ENP-handling workplaces. At the UNP workplaces, where concentration is high, real-time instruments should be used with caution. There are significant differences between the two SMPSs tested. TSI SMPS showed about 20% higher concentration than the Grimm SMPS in all workplaces. Conclusions: For nanoparticle measurement, CPC and SAM might be useful to find source of emission at laboratory and ENP workplaces instead of P-SMPS in the first stage. An SMPS is required to measure with high accuracy. Caution is necessary when comparing data from different nanoparticle measurement devices and RG-SMPSs.
Potential Harmful Effects of Bulk Titanium Dioxide in Risk and Hazard Assessment
조은혜,유선경,엄익춘,윤효정,노희영 한국환경분석학회 2016 환경분석과 독성보건 Vol.19 No.2
In 2010, approximately 400,000 tons of titanium dioxide (TiO2) was produced, used and imported in Korea. TiO2 is mainly used as a pigment in paints and paint additives and as a white colorant in foods, cosmetics, drugs, sunscreen, textiles, and toothpaste. To control risks and manage the health and safety concerns of TiO2, the potential risk assessment of TiO2 in humans was investigated in this article. All available reliable studies that investigated TiO2 toxicity were collected by searching the literature for relevant papers. For filling the data gap, the reproductive and developmental toxicity of TiO2 was evaluated using rats. The particle size of TiO2 assessed in this report was >100 nm (except nano-sized TiO2). In repeated inhalation toxicity test, the lung lymph node burdens of TiO2 increased in a concentration-dependent manner and inflammation was noted in bronchoalveolar lavage cells. The tumors observed in rats are thought to be secondary to particle overload in inhalation carcinogenicity studies. There was no indication of any reproductive toxicity in parent animals or developmental toxicity in pups. This study indicated that TiO2 possesses properties that have potential harmful impact on human health due to repeated dose toxicity and carcinogenicity via inhalation.
4대강 유역 및 공단지역 환경 중 PFOS 및 PFOA의 잔류수준 비교평가
조천래 ( Chon Rae Cho ),엄익춘 ( Ig Chun Eom ),김은주 ( Eun Ju Kim ),김수진 ( Sue Jin Kim ),최경희 ( Kyung Hee Choi ),조현서 ( Hyeon Seo Cho ),윤준헌 ( Jun Heon Yoon ) 한국환경분석학회 2009 환경분석과 독성보건 Vol.12 No.4
PFCs are group of fluorochemicals that have been produced and used for over 50 years for various purpose including soil/stain resistance and surfactant applications. These chemicals were degraded to Perfluorooctane sulfonate (PFOS) and Perfluorooctanoic acid (PFOA) that were kinds of persistence metabolites. Previous studies showed that these chemicals can be accumulated in various environmental media. In this study, the concentration level of PFOS and PFOA were measured in 59 samples collected from 4 major river watersheds and 6 industrial complex areas in 2006 and 2007. Mean concentration of PFOS in water, sediment and soil were N.D.-1180.0 ng/L, N.D.-9.17 ng/g dry-wt. and N.D.-10.97 ng/g dry-wt. respectively. Mean concentrations of PFOA in water, sediment and soil were N.D.-13850.0 ng/L, N.D.-2.07 ng/g dry-wt. and N.D.-1.04 ng/g drywt., respectively. The concentration of PFOS in water samples were significant difference among river, industrial complex stream and waste water treatment effluent (p<0.05). But PFOA were no significant difference among those samples. These results suggested that concentration of PFOS in water was direct effected by industrial complex activities.