미생물에 의한 생분해성 플라스틱의 생산과 이용

방원기,이일석 高麗大學校 自然資源科學硏究所 1996 自然資源科學硏究 Vol.4 No.-

Azotobacter sp.에 의한 Butyric Acid와 Valeric Acid로부터 Poly(3-hydroxybutyrate-co-3-hydroxyvalerate)의 생산

송희주,이일석,방원기 한국미생물생명공학회 ( 구 한국산업미생물학회 ) 1996 한국미생물·생명공학회지 Vol.24 No.1

Butyric acid 와 valeric acid로부터 poly(3-hydroxybutyrate-co-3-hydroxyvalerate) (P(3HB-co-3HV))를 생산하기 위하여 P(3HB-co-3HV)의 생산능력이 있는 10종의 균주를 토양으로부터 분리하였으며 분리된 균주들중에서 P(3HB-co-3HV)의 생산능력이 가장 우수한 균주 HJ-067을 선별하였고, Azotobacter sp.로 부분 동정하였다. P(3HB-co-3HV)의 생산에 있어서 butyric acid 와 valeric acid의 최적 기질 농도는 각각 3.0g/l이었다. 질소원으로는 (NH_4)_2SO_4가 가장 우수하였으며, 최적 농도는 0.75 g/l(C/N ratio=21.36)이었다. 금속이온(Zn^2+, Co^2+, Mn^2+)의 결핍은 P(3HB-co-3HV)의 생산에 영향을 미치며, 특히 Mn^2+을 첨가하지 않은 경우에 P(3HB-co-3HV)의 생산량이 증가하였다. P(3HB-co-3HV)의 생산을 위한 최적 배양 온도는 27℃였으며, 최적 초기 pH는 7.0이었다. 상기의 최적 조건하에서 36시간 배양하여 얻어진 건조균체량 및 P(3HB-co-3HV)의 생산량은 각각 3.00 g/l, 1.82 g/l이었다. 이때의 P(3HB-co-3HV) yield는 건조 균체량의 60.60%(w/w)이었으며, HV%는 15.92%(w/w)이었다. For the production of poly(3-hydroxybutyrate-co-3-hydroxyvalerate) (P(3HB-co-3HV)) from butyric acid and valeric acid, 10 strains of bacteria capable of producing P(3HB-co-3HV) wee isolated from soil. Among them, the strain HJ-067 showed the best ability of producing P(3HB-co-3HV), and was identified as a Azotobacter sp. For the production of P(3HB-co-3HV), the optimum concentrations of butyric acid and valeric acid were 3.0 g/l, respectively. The most effective nitrogen source was (NH_4)_2SO_4 at an optimum concentration of 0.75 g/l, which was equivalent to 21.36 in C/N ratio. Deficiency of the cationic metal ions (Zn^2+, Co^2+, Mn^2+) in the production medium had stimulating effect on P(2HB-co-3HV) accumulation, especially in the managanese deficient medium. The optimum temperature for P(3HB-co-3HV) production was 27℃ and the optimum initial pH was 7.0. Under the optimum conditions, 1.82 g/l of P(3HB-co-3HV) and 3.00 g/l of dry biomass were produced after 36 hour cultivation, and the P(3HB-co-3HV) yield and HV% were 60.60% (w/w), 15.92% (w/w), respectively.

Ascorbic Acid와 Pyrophosphate로부터 Ascorbic Acid-2-Phosphate의 효소적 생산

최현일,이상협,방원기 한국미생물생명공학회 ( 구 한국산업미생물학회 ) 1996 한국미생물·생명공학회지 Vol.24 No.5

Ascorbic acid (AsA)와 pyrophosphate로부터 ascorbic acid-2-phosphate (AsA2P)를 생산할 수 있는 미생물을 본 실험실에서 분리한 보존 균주로부터 선별하였다. 선별 균주 중에서 Cellulomonas sp. AP-7이 가장 높은 AsA2P 생산능을 나타내었다. 효소원으로 본 균주의 무세포 추출물을 이용하여 AsA와 PPi로부터 AsA2P의 최적 생산 조건을 조사하였다. AsA2P의 최적 생산을 위한 반응 혼합액은 효소원으로 21 mg/ml의 무세포 추출물, 150 mM sodium acetate 완충액(pH 4.5), 기질로 250 mM AsA 그리고 인산 공여체로 200 mM PPi로 조성되었으며, 이 반응 혼합액을 사용하여 33℃에서 48시간 반응시켰을 때, 31.9 mM의 AsA2P가 생산되었으며, 이는 반응에 사용한 AsA에 대해 12.76%의 수율에 해당하였다. Microorganisms capable of producing ascorbic acid-2-phosphate (AsA2P) from ascorbic acid (AsA) and pyrophosphate (PPi) wee screened from the culture collection of this laboratory. Among them Cellulomonas sp. AP-7 showed the highest productivity of AsA2P. The optimal conditions for the production of AsA2P from AsA and PPi with cell-free extract as an enzyme source wee investigated. The reaction mixture for the maximal production of AsA2P consisted of 21 g protein of cell-free extract per liter as the enzyme source, 250 mM AsA, 200 mM sodium pyrophosphate, 150 mM sodium acetate buffer (pH 4.5). By using this reaction mixture, 31.9 mM of AsA2P, which corresponded to a 12.76% yield based on AsA, was produced after incubation of 48 hr at 33℃.

Pseudomonas sp. JH007에 의한 DL-2-Chloropropionic Acid로부터 D-Lactic Acid의 생산

정자헌,황인균,방원기 한국미생물생명공학회 ( 구 한국산업미생물학회 ) 1996 한국미생물·생명공학회지 Vol.24 No.3

DL-2-chloropropionic acid로부터 D-lactic acid를 생산하기 위하여, 토양으로부터 DL-2-chloropropionic acid를 유일한 탄소원 및 에너지원으로 이용할 수 있는 균주 80여종을 분리하였으며, 분리균주들로부터 DL-2-chloropropionic acid로부터 D-lactic acid 생산성이 우수하며, L-lactic acid를 생산성이 우수하며, L-lactic acid를 생산하지 않은 균주 JH-007을 선별하여 Pseudomonas sp.로 동정하였다. DL-2-chloropropionic acid로부터 D-lactic acid를 생산하기 위한 최적 조건을 조사하기 위하여 3 g/l의 DL-2-chloropropionic acid가 포함된 LB 배지에서 배양하여 수확한 후 수확된 균체를 효소원으로 사용하였다. D-lactic acid 생산시 최적 반응액 조건은 125 mM sodium carbonate buffer에서 휴지균체 10 g/l와 3 g/l의 DL-2-chloropropionic acid를 사용할 때였으며, 최적 반응 pH는 10.0, 최적반응 온도는 30℃이었다. 최적조건하에서 반응액에 1 g/l의 DL-2-chloropropionic acid를 간헐적으로 첨가하여 5시간 반응시켰을 때 5.72 g/l의 D-lactic acid가 생산되었으며, 전환율은 98.4%였으며, 광학순도는 99.8%이었다. For the production of D-lactic acid from DL-2-chloropropionic acid, about 80 strains of bacteria capable of assimilating DL-2-chloropropionic acid as a sole carbon and energy source were isolated from the soil. JH-007 strain that showed the higest productivity of D-lactic acid and didn't produce L-lactic acid from DL-2-chloropropionic acid was selected from them and identified as Pseudomonas sp. The optimal conditions for the production of D-lactic acid from DL-2-chloropropionic acid were examined. The resting cells of JH-007 cultured in LB medium containing 3 g/l of DL-2-chloropropionic acid were used as an enzyme source. The reaction mixtures for the maximal production of D-lactic acid were consist of 10 g/l of resting cells and 3 g/l of DL-2-chloropropionic acid in 125 mM sodium carbonate buffer. The optimal pH for the reaction was 10.0 and the optimal temperature was 30℃. When 1 g/l of DL-2-chloropropionic acid was added intermittently to the reaction mixture under the above condition, 5.72 g/l of D-lactic acid was produced after incubation of 5 hrs. This amount of D-lactic acid corresponded to a 98.4% yields and the optical purity was 99.8%.

Structural bioinformatics approach to carbohydrate binding modules in carbohydrate hydrolyzing enzymes

Won-Gi Bang,In-Geol Choi 한국생물공학회 2008 한국생물공학회 학술대회 Vol.2008 No.10

Resolution of L-Carnitine from DL-Carnitine by Resting Cells of the Enterobacter sp. NH-104

( WON GI BANG ),( Ki Chul Hwang ) 한국미생물생명공학회 1998 Journal of microbiology and biotechnology Vol.8 No.6

Structural, optical and photoelectrochemical studies on the nanodispersed titania

Gi-Won Lee,So-Yeon Bang,Chaehyeon Lee,Won-Mok Kim,김동환,김경곤,박남규 한국물리학회 2009 Current Applied Physics Vol.9 No.5

Nanodispersion of aggregated TiO2 powders has been performed by microbead milling and its effect on photovoltaic performance has been investigated with dye-sensitized solar cell. Plasma-treated 30 um diameter zirconia beads are used to disperse the aggregated nanocrystalline TiO2 powders in ethanolic medium. Particle size distribution, surface area, film morphology, porosity, transmittance and haze are investigated with different milling speed. Microbead milling leads to a reduction of particle size, narrow size distribution and increase of surface area. A slight crystal phase transformation from anatase to rutile is also observed after microbead milling. Optical property is found to be influenced by microbead milling speed, where transmittance increases and haze decreases with increasing milling speed. Compared with photovoltaic performance of dye-sensitized solar cells based on titania before and after microbead milling, overall conversion efficiency is substantially improved from 4.46% to 6.31% after microbead milling at 2490 rpm for 90 min, corresponding to 42% increment, which is mainly due to a noticeable increase in photocurrent density, associated with highly dispersed characteristics. According to the photocurrent and photovoltage transient spectroscopic study, time constant for electron transport is hardly affected, while that for recombination is slightly decreased due to the increased surface area by nanodispersion.

Sequestration and Bioavailability of Organopollutants in Soil : Their Implication to the Risk Assessment

BANG, WON GI,Chung, Nam Hyun,Lee, Il Seok,Song, Hee Sang 한국환경농학회 2000 한국환경농학회지 Vol.19 No.5

The bioremediation is an economic technology to remove the organopollutants from soil. It is often found that the remediation could not remove the compounds below the levels determined by vigorous extractions as required by regulatory agencies. The reason for the reduced bioavailability with increasing time of aging has been accredited to the sequestration of the compounds in remote sites within or between soil particles. Then, the aging could be defined as the time-dependent sequestration. Partitioning and entrapment have been suggested as mechanism for aging. The rate and extent of the sequestration varies among dissimilar soils. The bioavailability of aged pollutants in soil could be measured by bioassays, mild solvent extraction, and soild-phase extractions. The sequestration could be affected by many factors including various soil properties, wetting and drying cycle, and the presence of cosolutes and NAPLs etc. The bioavailability and sequestration should be considered to determine the environmentally acceptable endpoint.

Structural, optical and photoelectrochemical studies on the nanodispersed titania

Lee, Gi-Won,Bang, So-Yeon,Lee, Chaehyeon,Kim, Won-Mok,Kim, Donghwan,Kim, Kyungkon,Park, Nam-Gyu Elsevier 2009 Current Applied Physics Vol.9 No.5

<P><B>Abstract</B></P><P>Nanodispersion of aggregated TiO<SUB>2</SUB> powders has been performed by microbead milling and its effect on photovoltaic performance has been investigated with dye-sensitized solar cell. Plasma-treated 30 μm-diameter zirconia beads are used to disperse the aggregated nanocrystalline TiO<SUB>2</SUB> powders in ethanolic medium. Particle size distribution, surface area, film morphology, porosity, transmittance and haze are investigated with different milling speed. Microbead milling leads to a reduction of particle size, narrow size distribution and increase of surface area. A slight crystal phase transformation from anatase to rutile is also observed after microbead milling. Optical property is found to be influenced by microbead milling speed, where transmittance increases and haze decreases with increasing milling speed. Compared with photovoltaic performance of dye-sensitized solar cells based on titania before and after microbead milling, overall conversion efficiency is substantially improved from 4.46% to 6.31% after microbead milling at 2490rpm for 90min, corresponding to 42% increment, which is mainly due to a noticeable increase in photocurrent density, associated with highly dispersed characteristics. According to the photocurrent and photovoltage transient spectroscopic study, time constant for electron transport is hardly affected, while that for recombination is slightly decreased due to the increased surface area by nanodispersion.</P>

강릉지역 동풍 기류 특성에 대한 사례 분석 연구

이선기(Sun-Gi Lee),김원기(Won-Gi Kim),김상국(Sang-Kook Kim),김도수(Do-Soo Kim),류시찬(Shi-Chan Ryu),전상식(Sang-Sik Jeon),박기원(Kee-Won Park),방소영(So-Young Bang),김연희(Yeon-Hee Kim),남재철(Jae-Cheol Nam) 한국기상학회 2005 대기 Vol.15 No.4