• 제목/요약/키워드: Biological Engineering

검색결과 9,444건 처리시간 0.101초

Effects of Impeller Geometry on the 11α-Hydroxylation of Canrenone in Rushton Turbine-Stirred Tanks

  • Rong, Shaofeng;Tang, Xiaoqing;Guan, Shimin;Zhang, Botao;Li, Qianqian;Cai, Baoguo;Huang, Juan
    • Journal of Microbiology and Biotechnology
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    • 제31권6호
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    • pp.890-901
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    • 2021
  • The 11α-hydroxylation of canrenone can be catalyzed by Aspergillus ochraceus in bioreactors, where the geometry of the impeller greatly influences the biotransformation. In this study, the effects of the blade number and impeller diameter of a Rushton turbine on the 11α-hydroxylation of canrenone were considered. The results of fermentation experiments using a 50 mm four-blade impeller showed that 3.40% and 11.43% increases in the conversion ratio were achieved by increasing the blade number and impeller diameter, respectively. However, with an impeller diameter of 60 mm, the conversion ratio with a six-blade impeller was 14.42% lower than that with a four-blade impeller. Data from cold model experiments with a large-diameter six-blade impeller indicated that the serious leakage of inclusions and a 22.08% enzyme activity retention led to a low conversion ratio. Numerical simulations suggested that there was good gas distribution and high fluid flow velocity when the fluid was stirred by large-diameter impellers, resulting in a high dissolved oxygen content and good bulk circulation, which positively affected hyphal growth and metabolism. However, a large-diameter six-blade impeller created overly high shear compared to a large-diameter four-blade impeller, thereby decreasing the conversion ratio. The average shear rates of the former and latter cases were 43.25 s-1 and 35.31 s-1, respectively. We therefore concluded that appropriate shear should be applied in the 11α-hydroxylation of canrenone. Overall, this study provides basic data for the scaled-up production of 11α-hydroxycanrenone.

A study of aldol condensation reaction product using a microreactor (마이크로 반응기를 적용한 알돌 축합반응 생성물 제조연구)

  • Kim Young-Jun;Lee Sang-Seo;Son Sung-Kwang;Song Kwang-Ho;Choe Jae-Hoon
    • Proceedings of the Korean Society of Precision Engineering Conference
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    • 한국정밀공학회 2006년도 춘계학술대회 논문집
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    • pp.543-544
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    • 2006
  • 3-methyl-2-cyclopentenone is a valuable reaction intermediate for various high value added products. 3-methyl-2-cyclopentenone is not only expensive but also difficult to produce. 3-methyl-2-cyclopentenone can be synthesized by base catalyzed intermolecular aldol condensation. In this work, we studied a simple and practical method for synthesizing 3-methyl-2-cyclopentenone. Experimental results showed the advantages of the continuous flow process using a microreactor with kenic mixers for the synthesis of 3-methyl-2-cyclopentenone.

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Production of ʟ-Theanine Using Escherichia coli Whole-Cell Overexpressing γ-Glutamylmethylamide Synthetase with Baker's Yeast

  • Yang, Soo-Yeon;Han, Yeong-Hoon;Park, Ye-Lim;Park, Jun-Young;No, So-young;Jeong, Daham;Park, Saerom;Park, Hyung Yeon;Kim, Wooseong;Seo, Seung-Oh;Yang, Yung-Hun
    • Journal of Microbiology and Biotechnology
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    • 제30권5호
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    • pp.785-792
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    • 2020
  • ʟ-Theanine, found in green tea leaves has been shown to positively affect immunity and relaxation in humans. There have been many attempts to produce ʟ-theanine through enzymatic synthesis to overcome the limitations of traditional methods. Among the many genes coding for enzymes in the ʟ-theanine biosynthesis, glutamylmethylamide synthetase (GMAS) exhibits the greatest possibility of producing large amounts of production. Thus, GMAS from Methylovorus mays No. 9 was overexpressed in several strains including vectors with different copy numbers. BW25113(DE3) cells containing the pET24ma::gmas was selected for strains. The optimal temperature, pH, and metal ion concentration were 50℃, 7, and 5 mM MnCl2, respectively. Additionally, ATP was found to be an important factor for producing high concentration of ʟ-theanine so several strains were tested during the reaction for ATP regeneration. Baker's yeast was found to decrease the demand for ATP most effectively. Addition of potassium phosphate source was demonstrated by producing 4-fold higher ʟ-theanine. To enhance the conversion yield, GMAS was additionally overexpressed in the system. A maximum of 198 mM ʟ-theanine was produced with 16.5 mmol/l/h productivity. The whole-cell reaction involving GMAS has greatest potential for scale-up production of ʟ-theanine.

Isolation and Characterization of Odor Treatment Bacteria (악취제거용 균주의 분리 및 특성)

  • Jeong Gwi-Taek;Lee Gwang-Yeon;Lee Kyoung-Min;Lee Hye-Jin;Ryu Hwa-Won;Kim Doman;Chough Sung-Hyo;Kim Si-Wouk;Cha Jin-Myoung;Jang Young-Seon;Park Don-Hee
    • KSBB Journal
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    • 제20권5호
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    • pp.345-349
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    • 2005
  • The microorganism for odor gas removal was isolated from sewage and contaminated soil. This was characterized as Pseudomonas sp. TKC by morphological, biochemical/physiological, and cultural characteristics analysis of the isolates. The optimum conditions for isolates growth were as follows; substrate concentration 500 ppm, initial medium pH 7.0, incubation temperature 30C, agitation speed 150 rpm, and MSM medium containing 3 g/L (NH4)2SO4.

Soil Washing and Biodegradation Potentials of Amphiphilic Polyurethane(APU) Nano-network Particles

  • Kim, Young-Bum;Jang, Shin-A;Kim, Ju-Young;Kim, Eun-Ki
    • 한국생물공학회:학술대회논문집
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    • 한국생물공학회 2000년도 춘계학술발표대회
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    • pp.442-445
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    • 2000
  • Amphiphilic polyurethane(APU) particle is a polymeric surfactant, and could increase the solubility of 2-methylnaphthalene significantly. 2-Methylnaphthalene was recovered by the precipitation of APU particles and was degraded by Acinetobacter sp. K2-2. APU particle was recovered and reused after treatment of triethylamine.

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