• Journal of Microbiology and Biotechnology
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• 제11권2호
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• pp.342-345
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• 2001

A bacterial strain PH-4, which produces an enzyme catalyzing the degradation of crosslinked poly(${\gamma}$-glutamic acid) hydrogels, was isolated and identified as a Flavobacterium sp. The enzyme was obtained by the sonication of the bacterial cells preincubated in a Bouillon medium with shaking, without adding of poly(${\gamma}$-glutamic acid) as an inducer. The products of the hydrogel degraded by the crude enzyme agreed closely with the depolymerized materials in SDS-polyacrylamide gel electrophoresis using methylene blue staining, and with a glutamic acid monomer on thin-layer chromatography, thereby suggesting that strain PH-4 produced a kind of exohydrolase.

• 설비공학논문집
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• 제27권12호
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• pp.645-651
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• 2015

This paper presents an experimental study on the freeze drying process for poly ${\gamma}$ glutamic acid. The physical properties of poly ${\gamma}$ glutamic acid are measured during the freeze-drying process. The moisture contents of poly ${\gamma}$ glutamic acid according to the glass transient temperature are obtained by DSC (Differential Scanning Calorimetry) analysis. The end point of primary drying for the poly ${\gamma}$ glutamic acid with a thickness of 3 mm is obtained by measuring the thickness of the dried layer, the amount of moisture evaporation, the moisture content, and the pressure in the drying vacuum chamber during the freeze-drying process. By considering the variation in the glass transient temperature with respect to the moisture content of the material, a control schedule for the heating plate temperature is suggested during the secondary drying process.

• 상하수도학회지
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• 제19권3호
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• pp.357-362
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• 2005

Poly-${\gamma}$-glutamic acid (${\gamma}-PGA$), which is extracted from fermented soybeans, is a high molecular weight, adhesive, and negatively charged(anionic) polymer. Recently, ${\gamma}-PGA$ has gained attention due to its potential as polymer. The objectives of this study were to examine the applicability of ${\gamma}-PGA$ as a coagulant and/or a coagulant aid, to evaluate the efficiency of ${\gamma}-PGA$ for the removal of Organic and Ammonium substance in wastewater treatment. The effect of coagulation was evaluated for the removal of SS and organic matter using poly aluminum chloride(PACI) as well as newly developed ${\gamma}-PGA$. The maximum COD removal rate of 63% and the SS of 78% were occurred at the dosage of 50mg/L ${\gamma}-PGA$ only. The most effective removal for particulate and organic matter was occured when both PACI and ${\gamma}-PGA$ were applied at the rate of 20:1(10mg/L PACI and 0.5mg/L ${\gamma}-PGA$). When mixed with PACI, only small portion of ${\gamma}-PGA$ was enough to improve removal efficiencies of organic and particulate matter in wastewater. This result showed the positive potential of ${\gamma}-PGA$ as a new coagulant materials for wastewater treatment.

• 방사선산업학회지
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• 제6권2호
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• pp.165-169
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• 2012

This study was conducted to determine the prevention effect of poly-gamma-glutamic acid (${\gamma}-PGA$) on tissue damage induced by gamma irradiation for development of xenograft. Porcine tendons were treated at various doses of ${\gamma}-PGA$ (0.1, 0.5, 1 and 5%) and then gamma-irradiated (30 kGy). Prevention effects on tissue damage were measured as the result of tensile strength, hydroxyproline contents and viscosity of ${\gamma}-PGA$. Tensile strength was remarkably decrease in gamma-irradiated porcine ligament, but increased by ${\gamma}-PGA$ treated one. Among the ${\gamma}-PGA$ treatment doses, 1% treated group showed the highest values of tensile strength compared to non-treated group. Hydroxyproline contents was significantly increased by gamma irradiation, but decreased by the ${\gamma}-PGA$ treatment. Particularly, 1 and 5% ${\gamma}-PGA$ treated group were exhibited lower values of hydroxyproline contents than other group. In the result of viscosity, gamma-irradiated ${\gamma}-PGA$ (1%) was remarkably increased. Base on the results, it demonstrated that gamma irradiation induces severe alteration of mechanical property and collagen contents on porcine ligament, but ${\gamma}-PGA$ can effectively prevent these tissue damage.

• 한국생물공학회:학술대회논문집
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• 한국생물공학회 2000년도 추계학술발표대회 및 bio-venture fair
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• pp.45-46
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• 2000

After cell removal from fermentation broth the supernatant containing poly (${\gamma}-glutamic acid$) (${\gamma}-PGA$) was concentrated by ultrafiltration in order to reduce the amount of organic solvents such as methanol, ethanol, propanol required for the recover of ${\gamma}-PGA$ with precipitation. The concentration and volume reduction of cell-free solution by ultrafiltration could reduce 3 times the amount of ethanol for the recover of ${\gamma}-PGA$ from cell-free fermentation broth.

• 한국식품영양학회지
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• 제25권3호
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• pp.677-684
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• 2012

Poly-${\gamma}$-glutamic Acid(${\gamma}$-PGA)를 다량 생산하는 균주를 우리나라의 전통발효식품인 청국장으로부터 Bacillus subtilis GS-2를 분리하였다. 이 균은 glutamic acid 의존형 균으로, 이 균에 의한 ${\gamma}$-PGA 생산 최적 조건을 검토한 바, 단순배지(L-glutamic acid 2.0%, glucose 1.0%, $NH_4Cl$ 0.5%, $KH_2PO_4$ 0.05%, $MgSO_4$ $7H_2O$ 0.01%, pH 7.0)로 진탕배양(220 rpm) 하였을 때, 배양시간 48시간, 최적온도 $33^{\circ}C$, 그리고 초기 pH 6.5로 나타났다. 영양원으로 glutamic acid 3%, sucrose 3%, $NH_4Cl$ 0.25%, $KH_2PO_4$ 0.15%, $MgSO_4$ $7H_2O$ 0.015%에서 ${\gamma}$-PGA 최대 생산량이 31.0 $g/{\ell}$이었다.

• Applied Biological Chemistry
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• 제40권3호
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• pp.173-177
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• 1997

Bacillus licheniformis 9945a는 액체배양시 ${\gamma}-poly(glutamic\;acid)$를 균체외로 분비하며, 한천배지에 고체 배양시는 점액질의 군락을 나타낸다. 점액질의 Bacillus속 세균의 형질전환은 그리 순하지 않은 것으로 알려져 있으며, B. licheniformis에서의 trasposon Tn10의 활성여부도 알려져 있지 않다. 그래서 점액질을 분비하지 않는, B. licheniformis의 자연발생적 변이주를 우선 분리하였다. Mini-Tn10을 함유한 plasmid pHV1248을 protoplast transformation법에 준해서 이 변이주에 도입하여 형질전환체를 분리하였다. pHV1248을 함유한 형질전환체를 점액성의 야생형질로 복귀시킨 후에, 가열처리함으로써 무작위 돌연변이를 유도하였다. Arginine, lysine 또는 tryptohan을 생육인자로 요구하는 돌연변이주들이 replica plating method에 의해서 분리되었고, 이 들 영양요구성 변이주는 mini-Tn10이 염색체 DNA상에 삽입됨으로써 생겨났음이 Southern blotting과 DNA-DNA 혼성화 실험으로 증명되었다. 이러한 pHV1248을 이용한 형질전환 및 돌연변이 유도방법은 Bacillus licheniformis 9945a의 다양한 변이체를 얻는데 유용할 것이다.

• 한국식품영양과학회지
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• 제35권3호
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• pp.255-261
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• 2006

칼슘은 한국인에게 가장 부족되기 쉬운 영양소로 섭취만큼이나 흡수가 중요한 요인이 되는 미네랄이다. 최근 칼슘흡수 증진에 효과가 있는 소재로 주목받고 있는 폴리 감마글루탐산(${\gamma}-PGA;\;poly-{\gamma}-glutamic\;acid)$이 체내 칼슘흡수에 미치는 영향을 알아보기 위해 4주령된 수컷 흰쥐(Sprague Dawley, female rats)를 이용하여 3주간 칼슘결핍식이를 급여시켜 칼슘결핍을 유도 후에, ${\gamma}-PGA$ 보충식이를 4주간 급여하였다. 실험군은 칼슘결핍군(Ca free group), 칼슘보충군(칼슘1.2% 보충군, total Ca 0.45%), 칼슘과 CPPl% 보충군(칼슘1.2%+CPP1% 보충군), 칼슘과 PGA1% 보충군(칼슘1.2%+${\gamma}-PGA1%$ 보충군), 칼슘과 CP1%+PGA1% 보충군(칼슘1.2%+CPP1%+${\gamma}-PGA1%$ 보충군), 칼슘과 PGA3% 보충군(칼슘1.2%+$\gamma$-PGA3% 보충군)으로 구분하였다. 이때 ${\gamma}-PGA$의 효과를 검증하기 위해 ${\gamma}-PGA$와 칼슘흡수 기전이 유사하고 이미 효능이 알려져 있는 casein phosphopeptide 보충군을 실험군에 추가하였다. 식이섭취량은 칼슘결핍군이 다소 낮았으나 유의적인 차이는 없었으며 칼슘섭취량도 유의적 차이 없이 비슷한 수준을 보였다. 변 및 뇨중 칼슘 배설량은 칼슘만을 섭취한 대조군에 비해 ${\gamma}-PGA$보충군에서 유의적으로 낮았다(p<0.05). 칼슘흡수율 또한 그룹간의 유의적 차이를 보여 칼슘만을 섭취한 그룹에 비해 ${\gamma}-PGA$를 함께 보충한 그룹의 흡수율이 30%더 높은 경향을 보였으며 이는 이미 효능이 알려진 CPP보다 우수한 수준이었다. 골형성 지표인 혈중 ALP를 측정한 결과 대조군에 비해 ${\gamma}-PGA$보충군이 유의적으로(p<0.05) 낮았고, 혈중 칼슘농도는 항상성을 유지하며 그룹간의 유의적 차이 없이 비슷한 수준을 보였으며 , OHPr/Cre도 유의적 차이는 없었다. 뼈 중 칼슘함량 및 강도는 칼슘결핍군이 나머지군에 비해 유의하게(p<0.03) 낮았으며, 칼슘함량의 경우 칼슘만을 보충한 그룹에 비해 ${\gamma}-PGA$를 함께 보충한 그룹이 농도 의존적으로 높은 칼슘함량을 보였고(p<0.05), 골강도의 경우는 유의적 차이는 없었으나 ${\gamma}-PGA$를 함께 보충한 그룹이 농도 의존적으로 골강도가 높은 경향을 나타내었다. 결론적으로 칼슘결핍을 유발한 흰쥐 에 칼슘만을 보충시켰을 때보다 칼슘과 함께 ${\gamma}-PGA$를 함께 보충했을 경우, 칼슘흡수 증진 및 골대사에 긍정적으로 기여함을 확인할 수 있었다. 그러나 좀 더 명확한 효과 검증을 위해서는 차후 많은 개체수와 장기간의 식이를 통한 반복실험, ${\gamma}-PGA$섭취수준에 따른 추가실험이 진행되어야 할 것으로 생각된다.

• Biotechnology and Bioprocess Engineering:BBE
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• 제11권3호
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• pp.251-257
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• 2006

The components of the media used to elicit the biosynthesis of $poly-{\gamma}-glutamic$ acid $({\gamma}-PGA)$ by Bacillus subtilis ZJU-7 were investigated, particularly the carbon and nitrogen sources Of the 7 carbon sources investigated, sucrose induced the highest rate of ${\gamma}-PGA$ productivity; among the nitrogen sources, tryptone had the best effect for ${\gamma}-PGA$ production. A $2^{6-2}$ fractional factorial design was used to screen factors that influence ${\gamma}-PGA$ production significantly, and a central composite design was finally adopted to formulate the optimal medium. ${\gamma}-PGA$ productivity improved approximately 2-fold when the optimal medium was used compared with the original nonoptimized medium, and volumetric productivity reached a maximum of 58.2 g/L after a 24-h cultivation period.

• Preventive Nutrition and Food Science
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• 제13권4호
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• pp.354-361
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• 2008

A novel bacterium isolated from Cheonggukjang was identified as a glutamate-dependent Bacillus subtilis HA with 98.3% similarity to Bacillus subtilis Z99104. Optimization of poly-$\gamma$-glutamic acid ($\gamma$-PGA) production by modulating fermentation factors including carbon sources, nitrogen sources, inorganic salts and fermentation time was investigated. Optimum culture broth for $\gamma$-PGA production consisted of 3% glutamate, 3% glucose and various salts, resulting in the PGA production of 22.5 g/L by shaking culture for 72 hr at $37^{\circ}C$. Average molecular weight of $\gamma$-PGA was determined to be 1,220 kDa through MALLS analysis. The $\gamma$-PGA solution showed a typical pseudoplastic flow behavior, and a great decrease in consistency below pH 6.0 regardless of the same molecular weight of $\gamma$-PGA. The molecular weights of isolated $\gamma$-PGA were drastically decreased by heat treatment in various acidic conditions, resulting in different hydrolysis of $\gamma$-PGA. The consistency of $\gamma$-PGA solution was greatly decreased with increase heating time in acidic conditions.