• Journal of Korean Society of Water and Wastewater
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• v.19 no.3
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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.

• Journal of Radiation Industry
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• v.6 no.2
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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.

• Journal of the Korean Society of Food Science and Nutrition
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• v.35 no.3
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• pp.255-261
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• 2006

This study was Conducted to investigate the effect of ${\gamma}-PGA\;({\gamma}-poly\;glutamic\;acid)$ on Ca absorption and bone metabolism in rats. Weaned 4-week old male rats were fed Ca-deficient diets for 3 weeks after the adjustment period. Rats were divided into 6 groups and were fed experimental diets for four weeks. Experimental groups were basal (Ca deficient), control (Ca diet: Ca 0.45%), CP1(Ca 0.45%+casein phosphopeptide 1%), PG1(Ca 0.45%+gamma poly glutamic acid 1%), CPG (Ca 0.45%+casein phosphopeptide 1%+gamma poly glutamic acid 1%) and PG3(Ca 0.45%+gamma poly glutamic acid 3%). Though daily Ca intake and food intake of experimental groups showed no significant difference that of control group. The values of fecal Ca excretion and urinary Ca excretion in groups fed ${\gamma}-PGA$ were significantly lower than that in tile control group. The values of Ca absorption in groups fed ${\gamma}-PGA$ were significantly higher than that in the control group. The levels of femur Ca in ${\gamma}-PGA$ supplemented group were significantly increased compared to the control group. Also, breaking force of femur in ${\gamma}-PGA$ supplemented group showed about 40% increase compared to the control group. These results show that ${\gamma}-PGA$ supplement could be helpful to increase Ca absorption as well as to intensify the femur strength and to increase the Ca content of femur in rats.

• Journal of Applied Biological Chemistry
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• v.54 no.1
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• pp.1-6
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• 2011

${\gamma}$-PGA(poly-${\gamma}$-glutamic acid) is an unusual anionic polypeptide that is made of D- and L-glutamic acid units connected by amide linkages between ${\alpha}$-amino and ${\gamma}$-carboxylic acid groups. ${\gamma}$-PGA has been isolated from many kinds of organisms. Many Bacillus strains produce ${\gamma}$-PGA as a capsular material of an extracellular viscous material. It is safe for eating as a viscosity element of fermented soybean products such as Chungkookjang and Natto. It is biodegradable, edible and nontoxic toward humans and the environment and its molecular weight varies from ten thousand to several hundred thousand depending on the kinds of strains used. Therefore, potential applications of ${\gamma}$-PGA and its derivatives have been of interest in the past few years in a broad range of industrial fields such as food, cosmetics, medicine, water-treatment, etc. In this study, a bacterium, Bacillus subtilis GS-2 isolated from the Korean traditional seasoning food, Chungkookjang could produce a large amount of ${\gamma}$-PGA with high productivity and had a simple nutrient requirement. Based on carbon utilization pattern and partial 16S rRNA sequence analysis, the GS-2 strain was identified as B. subtilis. The determination of purified ${\gamma}$-PGA was confirmed with thin layer chromatography (TLC), high performance liquid chromatography (HPLC), fourier transform infrared (FT-IR) spectra, and $^1H$-nuclear magnetic resonance ($^1H$-NMR) spectroscopy.

• Preventive Nutrition and Food Science
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• v.13 no.4
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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.

• Biotechnology and Bioprocess Engineering:BBE
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• v.11 no.3
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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.

• Journal of Microbiology and Biotechnology
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• v.20 no.4
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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.

• The Korean Journal of Food And Nutrition
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• v.25 no.3
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• pp.677-684
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• 2012

A bacterium strain GS-2 isolated from the Korean traditional seasoning food, Chungkookjang and was determined to produce large amounts of ${\gamma}$-PGA with high productivity when provided with simple nutrients (L-glutamic acid 2.0%, glucose 1.0%, $NH_4Cl$ 0.5%, $KH_2PO_4$ 0.05%, $MgSO_4{\cdot}7H_2O$ 0.01%, pH 7.0). In this study, the culture medium for this strain was optimized for the production of ${\gamma}$-PGA. The Bacillus subtilis GS-2 required supplementation with L-glutamic acid and other nutrients for maximal production of ${\gamma}$-PGA. The optimal culture conditions for ${\gamma}$-PGA production were a 48 hr culture time, a temperature of $33^{\circ}C$ and initial pH of 6.5 by rotary shaking (220 rpm). A maximum ${\gamma}$-PGA production of 31.0 $g/{\ell}$ was obtained with L-glutamic acid (30 $g/{\ell}$), sucrose (the main carbon source, 30 $g/{\ell}$), $NH_4Cl$ (the main nitrogen source, 2.5 $g/{\ell}$), $KH_2PO_4$ (1.5 $g/{\ell}$) and $MgSO_4{\cdot}7H_2O$ (0.15 $g/{\ell}$) in the culture medium.

• 한국생물공학회:학술대회논문집
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• 2000.11a
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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.

• Journal of Microbiology and Biotechnology
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• v.29 no.7
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• pp.1061-1070
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• 2019

In the present study, the optimization of poly(${\gamma}$-glutamic acid) (${\gamma}$-PGA) production by Bacillus sp. FBL-2 was studied using a statistical approach. One-factor-at-a-time method was used to investigate the effect of carbon sources and nitrogen sources on ${\gamma}$-PGA production and was utilized to select the most significant nutrients affecting the yield of ${\gamma}$-PGA. After identifying effective nutrients, response surface methodology with central composite design (CCD) was used to obtain a mathematical model to identify the optimum concentrations of the key nutrients (sucrose, $\text\tiny{L}$-glutamic acid, yeast extract, and citric acid) for improvement of ${\gamma}$-PGA production. The optimum amount of significant medium components appeared to be sucrose 51.73 g/l, $\text\tiny{L}$-glutamic acid 105.30 g/l, yeast extract 13.25 g/l, and citric acid 10.04 g/l. The optimized medium was validated experimentally, and ${\gamma}$-PGA production increased significantly from 3.59 g/l (0.33 g/l/h) to 44.04 g/l (3.67 g/l/h) when strain FBL-2 was cultivated under the optimal medium developed by the statistical approach, as compared to non-optimized medium.