• Journal of Microbiology and Biotechnology
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• 제4권3호
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• pp.210-214
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• 1994

The molecular weight of poly-hydroxybutyric acid (PHB) produced by Alcaligenes sp. K-912 is an important parameter characterizing the physical properties of the polymer. The effects of temperature and the levels of glucose, ammonium, phosphate and amino acids on the molecular weight of PHB were investigated. Molecular weight of PHB by temperature varied in the range of 380,000 to 550,000, 400,000 to 600,000 by glucose, 300,000 to 380,000 by phosphate, 400,000 to 1,000,000 by amino acids, respectively under the experimental conditions.

• KSBB Journal
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• 제10권4호
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• pp.386-392
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• 1995

The high viscous ${\gamma}$-polyglutamic acid(${\gamma}$-PGA) from alkalophilic Alcaligenes sp. was purified and its solution property was investigated. The intrinsic viscosities for Na+ form and H+ form of ${\gamma}$-PGA were 31.1 and 0.38d$\ell$/g, respectively. The viscosity of H+-PGA was not influenced by pH or salts while that of Na+-PGA was influenced. The intrinsic viscosity of Na+-PGA solution decreased remarkably at the alkaline or acidic pH and showed the sharp decrease when salts were added. ${\gamma}$-PGA exhibited the property of the polyelectrolyte showing the .sharp decrease of intrinsic viscosity by the addition of NaCl, and intrinsic viscosity of dilute solution with the low concentration of NaCl was exponentially dependent on temperature and its temperature dependency increased with increasing NaCl concentration. The chain stiffness, coil overlap parameter and critical concentration of Na+-PGA were 0.08, 5.25 and 0.07g/d$\ell$, respectively.

• KSBB Journal
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• 제10권5호
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• pp.547-552
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• 1995

Some functional and rheological properties of the ${\gamma}$-polyglutamic acid(${\gamma}$-PGA) produced from alkalophilic Alcaligenes sp. were investigated. Viscosity synergism with thickening agents, capacities for gelling, entrapig of heavy metals, and flocculability of ${\gamma}$-PGA were not observed, but the relatively good compatability with various polyvalent metallic ins, excellent absorption ability and spinability were observed. The ${\gamma}$-PGA solution showed non-Newtonian flow behavior and exhibited pseudoplastic property with a yield stress at above 1% concentration. The values of flow index for 1% solution were in the range of 0.41∼0.75 showing shear rate dependency and the value of yield stress was 2.28 Pa. The value of consistency index was 0.868 Pa$.$Sn and was exponentially dependent on concentration.

• 공업화학
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• 제31권6호
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• pp.612-623
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• 2020

본 연구는 Alcaligenes sp.와 Pseudomonas sp. 균주를 2종 혼합 배양 시, 혼합균주의 생장 및 인 제거에 5종의 중금속(Cd, Cu, Zn, Pb, Ni)이 미치는 저해효과를 정량적으로 평가하고자 수행되었다. 단일 중금속 처리 시 중금속별 Alcaligenes sp.와 Pseudomonas sp. 균주의 IC50는 Cd 0.75 mg/L, Cu 10.93 mg/L, Zn 7.08 mg/L, Pb 13.3 mg/L, Ni 15.78 mg/L 인 것으로 나타났다. 중금속 2종 처리 시 IC50는 Cd + Cu 처리구에서 가장 낮은 농도를 보였고, Ni + Pb 처리구에서 가장 높은 농도를 보였다. 단일 중금속 처리 시 중금속별 EC50 값은 Cd 0.54 mg/L, Cu 11.08 mg/L, Zn 6.14 mg/L, Pb 9.33 mg/L 및 Ni 13.81 mg/L이었다. 2종의 중금속 혼합 처리구별 EC50은 Cd + Zn 처리구에서 가장 낮은 농도, Zn + Ni 처리구에서 가장 높은 농도를 보였다. 2종 혼합 균주에 대한 2종 중금속 처리 결과 도출된 IC50 및 EC50 값을 기반 중금속 별 상호작용 평가 결과, 대부분 길항작용을 보이는 것으로 나타났으나, Cu + Ni 처리구에서는 상승작용을 보이는 것이 확인되었다. 따라서 본 연구 결과는 미생물을 이용한 오폐수 정화 처리 시 미생물의 성장 및 인 제거에 미치는 중금속의 독성으로 인한 저해효과에 대한 기초 자료를 제공할 수 있을 것으로 판단된다.

• KSBB Journal
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• 제8권3호
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• pp.217-223
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• 1993

호알카리성 Alcaligenes속의 한 균종응 이용하여 peptide계 생분해성 고분자인 ${\gamma}$-PGA( p이yglutarnic a acid}의 회분 맺 연속배양어l 의한 대량 생산성을 조사하였다. 화분배양시 ${\gamma}$-PGA의 생생량 벚 생산생은 포도당 농도 50g/P 까지 포도당의 농도증가에 따라 증가하였으나 최대 생산수율은 10gjP 의 포도당 농도 에서 얻어졌으며, 이때의 수율은 63% 이였다. 또, 비 증식속도는 포도당 농도 50g/l 에셔 약 $0.25hr^{-1}$로 최대값을 나타냈으나, 이 이상의 농도에서는 고농도 기섣에 의한 균체생육의 저해륜 나타내였다. 온도, pH 및 교반속도(rpm)를 독랩변수로 한 반응표면 분 석에 의한 ${\gamma}$-PGA 생산의 최적 희분배양 조건은 배 양온도 $31^{\circ}C$, pH 10 및 회전속도 87rpm의 정상점에 서 얻어졌으며, 이 조건에서 ${\gamma}$-PGA의 생산량은 약 11g/l 로 추정되었다. 연속배양의 경우 wash out은 희석률 0.5hr-1에서 일어났으며, 희석률 $0.40hr^{-1}$일 때 최대 생산성을 나타내였고, 최대 생산생은 2.80g/l/h로 회분배양보다 약 9배 높았다.

• 미생물학회지
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• 제32권3호
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• pp.232-237
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• 1994

Glutaryl 7-aminodeacetoxycephalosporanic acid(GL-7-ADCA)로부터 7-aminodeacetoxycephalosporanic acid(7-ADCA)를 생성하는 GL-7-ADCA acylase생산균을 자연계에서 폭넓게 검색하여 한균주를 선정하고 분리균의 형태 및 생리적 성질들을 조사하여 Alcaligenes sp.로 동정하였다. 분리균의 효소생산을 위한 배양조건을 검토한 결과 탄소원으로는 glucose, 질소원으로는 yeast extract, monosodium L-glutamate가 우수하였다. 효소의 작용최적 pH는 8.0이며, pH7.0~pH11.0 번위에서 비교적 안정하였다. 5l jar fermentor에서 배양경과를 조사한 결과 효소이 활성은 $37^{\circ}C$, 교반속도 300rpm, 통기량 1vvm 조건에서 20시간~30시간 배양시 가장 높았다.

• Journal of Microbiology
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• 제42권4호
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• pp.346-352
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• 2004

Poly(3-Hydroxybutyrate-co­3-Hydroxyvalerate), poly(3HB-co-3HV), copolyesters with a variety of 3HV contents (ranging from 17 to $60\;mol\%$) were produced by Alcaligenes sp. MT-16 grown on a medium containing glucose and levulinic acid in various ratios, and the effects of hydrophilicity and crystallinity on the degradability of the copolyesters were evaluated. Measurements of thermo-mechanical pro­perties and Fourier-transform infrared spectroscopy in the attenuated total reflectance revealed that the hydrophilicity and crystallinity of poly(3HB-co-3HV) copolyesters decreased as 3HV content in the copolyester increased. When the prepared copolyester film samples were non-enzymatically hydrolysed in 0.01 N NaOH solution, the weights of all samples were found to have undergone no changes over a period of 20 weeks. In contrast, the copolyester film samples were degraded by the action of extra­cellular polyhydroxybutyrate depolymerase from Emericellopsis minima W2. The overall rate of weight loss was higher in the films containing higher amounts of 3HV, suggesting that the enzymatic degra­dation of the copolyester is more dependent on the crystallinity of the copolyester than on its hydro­philicity. Our results suggest that the degradability characteristics of poly(3HB-co-3HV) copolyesters, as well as their thermo-mechanical properties, are greatly influenced by the 3HV content in the copoly­esters.

• Journal of Microbiology
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• 제35권4호
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• pp.360-364
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• 1997

A ${\beta}$-ketothiolase was purified 180-fold from the cell extracts of Alcaligenes sp. SH-69 by a series of chromatography on DEAE-Dephadex A-50, Sephacryl S-200, and hydrozyapatitie columns, The optimum pH values of the partially purified enzyme were 7.5 for condensation reaction and 8.3 for thiolysis reaction were estimated to be 0.12mM and $18.7\;{\mu}M$, respectively. The $K_m$ valued for acetoacetyl-CoA and free CoASH in the thiolusis in the condensation reaction was 0.70mM. The condensation reaction of the ${\beta}$-ketothiolase was inhibited even by low concentrations of free CoASH($K_i=30.4{\mu}M$). Pretreatment of the enzyme with NADH and NADPH markedly inhibited the thiolysis reaction of the enzyme. The potent inhibition of the enzyme by sulfhydryl reagents suggests the involvement of cystein residue in the active site.

• Journal of Microbiology
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• 제34권3호
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• pp.279-283
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• 1996

The weight average molecular weight of poly(3-hydroxybutyrate-co-3-hydroxyvalerate) synthesized by Alcaligenes sp. SH-69 was altered between $3.2$\times$10^5$ and $1.1$\times$10^6$ depending upon various culture conditions. It appeared that culture conditions favorable for the efficient production of copolyesters promoted the formation of higher molecular weight copolyesters. Polydispersity indices of isolated copolyesters were in the range of 1.5 to 2.5.

• 한국환경과학회:학술대회논문집
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• 한국환경과학회 2020년도 정기학술대회 발표논문집
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• pp.158-158
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• 2020