• 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.

• 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.

• 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.

• Food Science and Biotechnology
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• 제14권5호
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• pp.704-708
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• 2005

Poly-y-glutamate (${\gamma}$-PGA) has great potential as a biodegradable polymer in a broad range of industrial fields such as food, cosmetics, medicine and water treatment. In order to isolate ${\gamma}$-PGA producers that are suitable for specific industrial applications, 653 Bacillus-like strains were isolated from 439 varieties of three Korean fermented foods, Cheongkukjang, Doenjang, and Kochujang, which were collected from different regions across Korea. A very high level of ${\gamma}$-PGA production was demonstrated in 4.7%, 1.8%, and 3.0% of the Bacillus-like strains isolated from Cheongkukjang, Doenjang, and Kochujang samples, respectively, which produced a viscous substance to such extent that it overflowed to the lid of the plate on the glutamate-dependent ${\gamma}$-PGA production plates. On glutamate-independent ${\gamma}$-PGA production plates, 5.1%, 5.9%, and 6.1% of Bacillus-like strains isolated from Cheongkukjang, Doenjang, and Kochujang samples, respectively, showed high production. The maximum ${\gamma}$-PGA production yields were 32.5 g/L and 5 g/L, depending on the purification methods in the glutamate-dependent media, with the higher yield resulting from a simple precipitation of ${\gamma}$-PGA by either methanol or ethanol and dialysis. The viscous substance produced by each strain showed different morphological characteristics, suggesting that isolated ${\gamma}$-PGA producers could produce various types of ${\gamma}$-PGA.

• Journal of Microbiology and Biotechnology
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• 제29권7호
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• pp.1078-1082
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• 2019

Poly-${\gamma}$-glutamate (${\gamma}$-PGA) has various applications due to its desirable characteristics in terms of safety and biodegradability. Previous studies have been conducted on ${\gamma}$-PGA hydrogels produced by ${\gamma}$-ray irradiation, but these hydrogels have proved unstable in solutions. This study was conducted to enable the ${\gamma}$-PGA hydrogel to maintain a stable form in solutions. The ${\gamma}$-PGA mixture for UV-irradiation was prepared with a cross-linker (N,N,N-trimethyl-3-[(2-methylacryloyl)amino]propan-1-aminium). Both ${\gamma}$-PGA hydrogels' characteristics, including stability in solutions, were examined. The UV-irradiated ${\gamma}$-PGA hydrogel maintained a stable form during the nine weeks of the study, but the ${\gamma}$-ray irradiated hydrogel dissolved after one week.

• Journal of Microbiology and Biotechnology
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• 제20권4호
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• pp.803-808
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• 2010

Poly-${\gamma}$-glutamic acid (${\gamma}$-PGA) is a natural edible polypeptide in which glutamate is polymerized via ${\gamma}$-amide linkages. First, we assessed the eye irritancy potential of ${\gamma}$-PGA in rabbits. Additionally, we studied the effects of ${\gamma}$-PGA on corneal wound healing, due to the anti-inflammatory properties and water retaining abilities of ${\gamma}$-PGA. In this study, the effects of ${\gamma}$-PGA on corneal wound healing after an alkali burn were evaluated. Thirty eyes wounded by alkali burning in 30 white rabbits were divided into three groups: group A was treated with 0.1% 5,000 kDa ${\gamma}$-PGA for 2 days; group B was treated with 0.1% hyaluronic acid; and group C was not treated, as a control. The area of corneal epithelial defect was examined at 12, 24, 30, 36, 42, and 48 h after corneal alkali wounding to determine initial wound healing. We found that ${\gamma}$-PGA promoted corneal wound healing, compared with controls, and showed similar effects to hyaluronic acid. These results indicate that ${\gamma}$-PGA stimulates corneal wound healing by an anti-inflammatory effect and enhancing cell migration and cell proliferation. ${\gamma}$-PGA is a promising biomaterial that may be a substitute for hyaluronic acid in corneal wound healing treatment.

• Journal of Microbiology and Biotechnology
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• 제22권12호
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• pp.1782-1789
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• 2012

We have developed a novel type of polymer nanogel loaded with anticancer drug based on bio-derived poly(${\gamma}$-glutamic acid) (${\gamma}$-PGA). ${\gamma}$-PGA is a highly anionic polymer that is synthesized naturally by microbial species, most prominently in various bacilli, and has been shown to have excellent biocompatibility. Thiolated ${\gamma}$-PGA was synthesized by covalent coupling between the carboxyl groups of ${\gamma}$-PGA and the primary amine group of cysteamine. Doxorubicin (Dox)-loaded ${\gamma}$-PGA nanogels were fabricated using the following steps: (1) an ionic nanocomplex was formed between thiolated ${\gamma}$-PGA as the negative charge component, and Dox as the positive charge component; (2) addition of poly(ethylene glycol) (PEG) induced hydrogen-bond interactions between thiol groups of thiolated ${\gamma}$-PGA and hydroxyl groups of PEG, resulting in the nanocomplex; and (3) disulfide crosslinked ${\gamma}$-PGA nanogels were fabricated by ultrasonication. The average size and surface charge of Dox-loaded disulfide cross-linked ${\gamma}$-PGA nanogels in aqueous solution were $136.3{\pm}37.6$ nm and $-32.5{\pm}5.3$ mV, respectively. The loading amount of Dox was approximately 38.7 ${\mu}g$ per mg of ${\gamma}$-PGA nanogel. The Dox-loaded disulfide cross-linked ${\gamma}$-PGA nanogels showed controlled drug release behavior in the presence of reducing agents, glutathione (GSH) (1-10 mM). Through fluorescence microscopy and FACS, the cellular uptake of ${\gamma}$-PGA nanogels into breast cancer cells (MCF-7) was analyzed. The cytotoxic effect was evaluated using the MTT assay and was determined to be dependent on both the concentration and treatment time of ${\gamma}$-PGA nanogels. The bio-derived ${\gamma}$-PGA nanogels are expected to be a well-designed delivery carrier for controlled drug delivery applications.

• Journal of Microbiology and Biotechnology
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• 제27권2호
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• pp.412-415
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• 2017

Prebiotics improve the growth or activities of specific microbial genera and species in the gut microbiota in order to confer health benefits to the host. In this study, we investigated the effect of poly-gamma-glutamate (${\gamma}-PGA$) as a prebiotic on the gut microbiota of mice and the organ distributions of ${\gamma}-PGA$ in mice. Pyrosequencing analysis for 16S rRNA genes of bacteria indicated that oral administration of ${\gamma}-PGA$ increased the abundance of Lactobacillales while reducing the abundance of Clostridiales in murine guts. It is suggested that oral administration of ${\gamma}-PGA$ can be helpful for modulating the gut microbiota as a prebiotic.

• 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.