• Title/Summary/Keyword: culture pH

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Production and characterization of ultra-high-molecular weight poly(3-hydroxybutyrate) by recombinant Escherichia coli

  • Park, Jong-Pil;Park, Si-Jae;Lee, Sang-Yeop
    • 한국생물공학회:학술대회논문집
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    • 2001.11a
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    • pp.731-734
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    • 2001
  • An efficient fermentation strategy for the high level production of ultra-high-molecular weight poly(3-hdyroxybutyrate) (PHB) was developed. Although the cell and PHA concentrations obtained by flask cultures at different initial pH (6.0 or 6.9) were almost same level, the molecular mass of PHB produced were quite different along with the initial pH. When a recombinant Escherichia coli XL1-Blue harboring pJC2 containing the Alcaligenes latus PHB biosynthesis genes was cultivated in flask culture (pH 6.0), the PHB having a very high molecular weight of 22 MDa could be produced while only below 1 MDa at initial pH 6.9. The ultra-high-molecular weight PHB could be synthesized to high concentration of 89.8 g/L resulting in the PHB productivity of 2.07 g/L-h by simple fed-batch culture. In this study, we report that PHB having various molecular mass can be produced by employing metabolically engineered E. coli strains harboring the plasmids of different copy numbers containing the A. latus phbCAB genes.

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Isolation of endosulfan degrading bacteria and their degradation characteristics (유기염소계 농약 endosulfan을 분해하는 미생물의 분리 및 분해 특성)

  • Shin, Jae-Ho;Kwak, Yun-Young;Kim, Won-Chan;So, Jai-Hyun;Shin, Hyun-Soo;Park, Jong-Woo;Kim, Tae-Hwa;Kim, Jang-Eok;Rhee, In-Koo
    • Korean Journal of Environmental Agriculture
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    • v.27 no.3
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    • pp.292-297
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    • 2008
  • A bacterium, which was named to be Bacillus sp. E64-2, capable of degrading endosulfan was isolated from the environmental sample using enrichment culture technique. The Bacillus sp. E64-2 was able to degrade 99% of 10 mg/L endosulfan in the culture media within 7 days at $30^{\circ}C$. Endosulfan diol was the only intermediate by the endosulfan degrading bacterial culture and the pH value of the culture media was significantly increased to pH 8.4 from pH 7.0 after 7 days of incubation. When the endosulfan and the crude extract of the strain were incubated, endosulfan diol was a major metabolite. Both the enzymatic reaction and the pH-increasing effect contribute to the degradation of endosulfan by the bacterial culture.

Solid Medium pH-Dependent Antifungal Activity of Streptomyces sp. Producing an Immunosuppressant, Tautomycetin (면역억제제 Tautomycetin을 생산하는 방선균의 고체배지 pH에 따른 항진균 활성)

  • Hur, Yoon-Ah;Choi, Si-Sun;Chang, Yong-Keun;Hong, Soon-Kwang;Kim, Eung-Soo
    • Microbiology and Biotechnology Letters
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    • v.35 no.1
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    • pp.26-29
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    • 2007
  • Tautomycetin (TMC), which is produced by Streptomyces sp. CK4412, is a novel activated T cell-specific immunosuppressive compound with an ester bond linkage between a terminal cyclic anhydride moiety and a linear polyketide chain bearing an unusual terminal alkene. Antifungal activity against Aspergillus niger and TMC productivity assayed by HPLC using culture extracts from Streptomyces sp. CK4412 grown on solid medium adjusted at various pH were measured. The cells cultured at acidic pH (pH 4-5) medium exhibited much stronger antifungal activity as well as higher TMC productivity than those cultured at neutral pH medium, implying that the acidic pH-shock should be an efficient strategy to induce the productivity of secondary metabolites in Streptomyces culture.

Morphological Changes by Submerged Culture Conditions for the Mycelial Optimal Growth of Cordyceps sinensis and Immunological Properties of Hot Water Extract of Mycelium (동충하초 균사체 최적 성장을 위한 심부배양 조건에 따른 형태학적 변화 및 균사체 열수 추출물의 면역학적 특성)

  • Suh, Hyung-Joo;Choi, Jang-Won
    • KSBB Journal
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    • v.25 no.1
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    • pp.47-54
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    • 2010
  • The mycelial dispersed growth of Cordyceps sinensis was optimized in submerged batch culture at initial pH of 5.0, 150 rpm, and $25^{\circ}C$. The morphological data showed much more dispersed growth of C. sinenesis at initial pH of 5.0. Also, projected area, main hyphal length and number of tips for the mycelial growth of initial pH 5.0 were higher than those of other initial pHs. The industrial medium for mycelial production of C. sinensis was determined to be molasses of 100 g and crushed brewery yeast of 10 g per liter as carbon and nitrogen sources, respectively. With these culture conditions, the maximum production of mycelia was approximately 30.0 g per liter by batch culture in 5-liter jar fermenter with no controlled pH. This result suggests that large-scale mycelia production of C. sinensis may be possible in submerged batch culture. The hot water extract of mycelia from C. sinensis was mainly composed of 83.0% carbohydrate, 11.8% protein, 1.9% lipid, and 2.4% ash and there were present glucose, mannose, galactose, and arabinose as molar ratio of 8.79 : 2.59 : 1.34 : 1.0 in the carbohydrate, respectively. In the experiment using spleen cell and macrophage, the extract showed potent mitogenic and immuno-stimulating activities and among various components, an important factor that contribute to the immunological activities was turned out to be carbohydrate moiety.

Optimization of Major Culture Elements on Growth and Shikonin Production in the Lithospermum erythrorhizon Hairy Root Culture

  • Hwang, Ok-Jin;Kim, Yu-Jeong;Sung, Nak-Sul;Ahn, Jun-Cheul;Kim, Sik-Eung;Hwang, Baik
    • Korean Journal of Medicinal Crop Science
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    • v.10 no.4
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    • pp.243-248
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    • 2002
  • The effects of basal media, carbon, nitrogen, phosphate and some major macro elements on growth and shikonin production in Lithospermum erythrorhizon hairy root culture were studied. Among examined media, growth of hairy root cultured in B5 liquid medium was rapid, whereas shikonin production was high in MS liquid medium. Under B5 basal medium, sucrose concentration for optimal growth and shikonin production was 9% and 4% respectively. The growth and shikonin production on pH changes in B5 medium resulted little effect in pH 5.8 to pH 8.8 ranges, whereas growth was decreased dramatically in both above 8.8 and under 5.8. Nitrogen source and concentration effected on the growth and shikonin production. The highest growth rate was in B5 medium (50 mM $KNO_3$ and 1 mM $NaH_2PO_4)$, whereas the highest shikonin production was in the condition supplemented with 5 mM $KNO_3$ and 10 mM $NaH_2PO_4$.

Development of Curdlan Separation Process with Density Gradient Centrfugation (Density Gradient를 이용한 식품소재를 커들란의 분리공정개발)

  • 김봉영;이중헌
    • KSBB Journal
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    • v.16 no.5
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    • pp.523-525
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    • 2001
  • Curdlan is one biopolymer composed of ${\beta}$1,3-glucan and dissolved in a alkali solution but formed salt under neutral or acid condition. It was produced by Agrobactrium species and the separation process is necessary to make pure curdlan from the culture broth. The pH swing separation method was as feasible separation process using solubility changes with the pH difference. however, this method requires a lot of acid and alkali solution also produces a lot of waste. Therefore, an efficient process which could save energy and minimize toxic waste was developed. A density gradient separation process was developed in this research. High density sucrose solution was used as a separation agent. Curdlan was separated from the culture broth when the density of the sucrose solution was 1.15 g/L. Since the curdlan was produced on the surface of cell wall. the pre-treatment of culture broth was necessary. Curdlan recovery yield was increased up to 83% with the homogenization of the culture broth and further increased up to 87% with the treatment of alkai-acid solution.

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Two-Stage Fermentation for 2-Ketogluconic Acid Production by Klebsiella pneumoniae

  • Sun, Yuehong;Wei, Dong;Shi, Jiping;Mojovic, Ljiljana;Han, Zengsheng;Hao, Jian
    • Journal of Microbiology and Biotechnology
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    • v.24 no.6
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    • pp.781-787
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    • 2014
  • 2-Ketogluconic acid production by Klebsiella pneumoniae is a pH-dependent process, strictly proceeding under acidic conditions. Unfortunately, cell growth is inhibited by acidic conditions, resulting in low productivity of 2-ketogluconic acid. To overcome this deficiency, a two-stage fermentation strategy was exploited in the current study. During the first stage, the culture was maintained at neutral pH, favoring cell growth. During the second stage, the culture pH was switched to acidic conditions favoring 2-ketogluconic acid accumulation. Culture parameters, including switching time, dissolved oxygen levels, pH, and temperature were optimized for the fed-batch fermentation. Characteristics of glucose dehydrogenase and gluconate dehydrogenase were revealed in vitro, and the optimal pHs of the two enzymes coincided with the optimum culture pH. Under optimum conditions, a total of 186 g/l 2-ketogluconic acid was produced at 26 h, and the conversion ratio was 0.98 mol/mol. This fermentation strategy has successfully overcome the mismatch between optimum parameters required for cell growth and 2-ketogluconic acid accumulation, and this result has the highest productivity and conversion ratio of 2-ketogluconic and produced by microorganism.

Effects of Carbon, Nitrogen Sources and pH on Direct Somatic Embryogenesis in Liquid Culture of Rehmannia glutinosa Lib. (지황의 액체배양에서 탄소원.질소원 및 pH가 직접 체세포배 형성에 미치는 영향)

  • Chae, Young-Am;Park, Ju-Hyun
    • Korean Journal of Medicinal Crop Science
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    • v.7 no.1
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    • pp.1-6
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    • 1999
  • Basic informations for direct somatic embryo formation in Rehmannja glutinosa Lib. were obtained in 500ml erlenmyer flask. The ratio of ammonium to nitrate nitrogen of 825(mg/l) : 1900(mg/l) was proper condition for somatic embryo formation from stem and petiole explants and 3% sucrose was the most effective carbon source. Full strength MS medium with 2mg/l BA was better than LS medium for somatic embryogenesis. The initial pH 5.7 of medium(full strength MS with 2.0mg/l BA and 0.1mg/l NAA) was good for embryo production. Potassium ion was taken up rapidly within 2 weeks. while $Ca^{++}$ and $Mg^{++}$ ion contents were almost constant during culture period. Sucrose hydrolysis occurred throughout the culture, while glucose and fructose were absorbed simultaneously from the third week of culture.

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Optimization of Submerged Culture Conditions for the Production of Ginseng Root Using Response Surface Method (반응표면분석법을 이용한 인삼 Root 액체배양조건의 최적화)

  • 오훈일;장은정;이시경;박동기
    • Journal of Ginseng Research
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    • v.24 no.2
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    • pp.58-63
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    • 2000
  • To develop the production of ginseng root using plant tissue culture technology, submerged culture conditions were optimized by means of the fractional factorial design with 4 factors and 3 levels by a RSM computer program. The ginseng (Panax ginseng C. A. Meyer) roots induced by plant growth regulators were cultured on SH medium and the effects of various pH of medium, sucrose concentration, nitrogen concentration and phosphate concentration on fresh weight of the ginseng root were investigated. The fresh weight of ginseng root increased with a decrease in nitrogen concentration and fresh weight of ginseng root varied from 1.00 to 2.33g under various conditions. The optimum pH of medium and sucrose concentration determined by a partial differentiation of the model equation, nitrogen and phosphate concentration were pH 5.6, sucrose 3.8%, nitrogen 50 mg/L and phosphate 80.7 mg/L, respectively. Under these conditions, the predicted growth of ginseng root was estimated to be 2.36g.

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Growth Optimization of Photorhabdus luminescens Isolated from Entomopathogenic Nematode Heterorhabditis bacteriophora (병원성 선충 Heterorhabditis bacteriophora에서 분리된 공생 박테리아 Photorhabdus luminescens의 생장조건)

  • Yoo, Sun Kyun;Randy Gaugler;Christopher W. Brey
    • Microbiology and Biotechnology Letters
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    • v.29 no.2
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    • pp.104-109
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    • 2001
  • The yield of infective juveniles of Heterorhabditis bacteriophora (Tf strain) in vitro monoxenic liquid culture was improved significantly as the amount of symbiont biomass, Photorhabdus sp. strain Tf, increased. To investigate the influence of abiotic factors on the growth and biomass production of Photorhabdus sp. strain Tf, triplicate flask cu1tmes were performed. The optinal temperature and medium pH for the growth of Photorhahdus sp. strain Tf were 30$^{\circ}$C and between pH 5.5-7.3, respectively. Aeration also improved greatly growth and yield of biomass of Photorhabdus sp. strain Tf. Photorhabdus sp. strain Tf in batch fermentation showed growth-associated pattem in terms of pigment production, and the pH of culture medium rose steadily until growth stopped dUling the fermentation. Both pigment production and culture pH rise would be useful parameters indicating a reliable growth of Photorhabdus sp. strain Tf.

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