• Title, Summary, Keyword: Microbial Culture

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Biocatalytic Production of Aldehyde by a Methanol Utilizing Yeast, Hansenula nonfermentans KYP-l Grown in Methanol-limited Continuous Culture

  • Yoon, Byung-Dae;Kim, Hee-Sik;Kwon, Tae-Jong;Yang, Ji-Won;Kwon, Gi-Seok;Lee, Hyun-Sun;Ahn, Jong-Seog;Mheen, Tae-Ick
    • Journal of Microbiology and Biotechnology
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    • v.2 no.4
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    • pp.278-283
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    • 1992
  • Aldehyde production by cells of a methanol utilizing yeast, Hansenula nonfermentans KYP-1 was improved when they were grown in a methanol-limited continuous culture, in comparison with cells grown in a batch culture. A higher cell yield was also obtained in continuous culture than in batch culture. This could be due to the fact that a lower methanol concentration was maintained in the jar fermentor to minimize growth inhibition by methanol. A maximum cell productivity of 0.219 g.$liter^{-1}.hr^{-l}$ and a cell yield of 47% were obtained at dilution rates of 0.1 $hr{-1}$ and 0.06 hr{-1}, respectively. The greatest amount of aldehyde was measured at a dilution rate of 0.08 $hr{-1}$. Under optimum reaction conditions, 915.7 mM of acetaldehyde was produced from 1.5 M ethanol after 21 hours reaction, with a conversion rate of 61%. Propionaldehyde and acrolein were produced with conversion rates of 32.7% and 44%, respectively.

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Effects of Mixing Conditions on the Production of Microbial Cellulose by Acetobacter xylinum

  • Lee, Hei-Chan;Xia Zhao
    • Biotechnology and Bioprocess Engineering:BBE
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    • v.4 no.1
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    • pp.41-45
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    • 1999
  • Microbial cellulose has many potential applications due to its excellent physical properties. The production of cellulose from Acetobacter xylinum in submerged culture is, however, beset with numerous problems. The most difficult one has been the appearance of negative mutants under shaking culture conditions, which is deficient of cellulose producing ability. Thus genetic instability of Acetobacter xylinum under shaking culture condition made developing a stable mutant major research interest in recent years. To find a proper type of bioreactor for the production of microbial cellulose, several production systems were developed. Using a reactor system with planar type impeller with bottoms sparging system, it was possible to produce 5 g/L microbial cellulose without generating cellulose minus mutants, which is comparable to that of static culture system.

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Nitroglycerin Biodegradation under Denitrification Conditions and Corresponding Microbial Community Shifts upon Acclimation (탈질조건에서 nitroglycerin의 생물학적 분해 동역학 및 미생물 군집 변화)

  • Choi, Wonchul;Bae, Bumhan
    • Journal of Soil and Groundwater Environment
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    • v.24 no.5
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    • pp.42-54
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    • 2019
  • Biodegradation of an explosive compound, glyceryl trinitrate (GTN), was studied with a denitrifying microbial culture grown in a sequencing batch reactor and a GTN acclimated denitrifying culture. The GTN acclimated culture, which were fed on GTN for 1 month, degraded GTN regioselectively via denitration on C1 position as compared to C2 position denitration by denitrifying culture that has never been exposed to GTN. Accumulation of two isomeric glyceryl dinitrates (GDNs) in both culture medium suggests that GDN denitration is the rate-limiting step in GTN biodegradation. The first order GTN degradation rate normalized to cell concentration of the acclimated culture was calculated to be 0.045 (${\pm}0.002$) L/g-hr. Increasing concentration of electron acceptor(nitrate) resulted in discouraged GTN degradation. According to microbial community analysis, prolonged GTN exposure resulted in 25% increase in the genus level of the GTN acclimated culture with the disappearance of two dominating denitrifying microbial species of Methyloversatilis universalis and Hyphomicrobium zavarzinii in the denitrifying culture.

Evaluation of Riverine Microbial Diversity using the Culture-Independent Genetic Fingerprinting Technique (T-RFLP) (유전자지문분석법(T-RFLP)을 이용한 하천 미생물의 다양성 평가)

  • Jeong, Ju-Yong;Lee, Kyong-Hee
    • Journal of Korean Society on Water Environment
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    • v.24 no.2
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    • pp.195-200
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    • 2008
  • To analyze the riverine microbial community structure, genetic fingerprints and ecological indexes such as species abundances, diversity, evenness, dominance of targeted rivers in Gyeonggi Province were acquired and evaluated using terminal restriction fragment length polymorphism (T-RFLP) technique. Genetic fingerprinting technique such as T-RFLP, which is able to show the microbial community clearly unlike traditional culture-dependent techniques, was thought to be useful to analyse the riverine microbial ecosystem under various factors. Riverine ecosystem evaluation using visible organisms would give biased results with time, targeted organism and researcher. But, T-RFLP, which can exclude the subjected biases such as culture condition and identification, would be an option to understand natural ecosystem by including the microorganisms that defy culture but perform important functions.

Effects of Microbial feed Additive and vitamin-C as an Alternative to Antibiotic on Growth Performances and Carcass Characteristics of Meat Cows (항생제 대체제로서 미생물배양액 및 vitamin-C 급여가 육우의 증체 및 도체형질에 미치는 영향)

  • Nam, In-Sik;Han, Chang-Su;Ahn, Jong-Ho
    • Korean Journal of Organic Agriculture
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    • v.23 no.3
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    • pp.523-534
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    • 2015
  • Twenty four Holstein steers (average body weight $714{\pm}13.60kg$) were used in this experiment to determine the effect of supplementing of microbial culture and coated vitamin-C on growth performances and carcass characteristics in finishing Holstein steers. Holstein steers were randomly assigned to feeding groups of control group (Con, 12 kg of basal diet/head/day), microbial culture group (MC, 12 kg of basal diet + 30 g of microbial culture/head/day) and coated vitamin-C group (CVC, 12 kg of basal diet + 10 g of coated vitamin-C/head/day). MC and CVC groups were higher in ADG compared to control (P<0.05). FCR was also lower in MC and CVC groups than control group (P<0.05). Back fat thickness, rib-eye area, marbling score, meat color and yield index were not changed by supplementing microbial culture and coated vitamin-C. MC group was higher for maturity compared to control and CVC group (P<0.05). CVC group was higher for fat color compared to control and MC group (P<0.05). Based on the results obtained from the current study, supplementation of microbial culture and coated vitamin-C as an alternative to antibiotic might increase growth performances and enhance carcass characteristics in finishing Holstein steers. However, more studies are needed to find out the optimum supplementing period of microbial culture or coated vitamin-C for high quality meat production from Holstein steers.

Studies on the Culture of Ergot Fungus(IV) -Culture of Korean Ergot Fungus- (맥각균(麥角菌)의 배양(培養)에 관한 연구(硏究)(IV) -한국산(韓國産) 맥각균(麥角菌)의 배양(培養)-)

  • Kim, Byong-Kak;Shim, Mi-Ja;Choi, Eung-Chil;Park, Young-In
    • Korean Journal of Pharmacognosy
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    • v.6 no.1
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    • pp.9-13
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    • 1975
  • To isolate ergot strains which are capable of growing and producing alkaloids in submerged culture, strains were isolated from the sclerotia parasitizing the Graminae plants in Korea and the experiments of submerged culture of these strains yielded the following results: 1) The mycelia which were respectively isolated from the sclerotia parasitizing Agropyron semicostatum $N_{EES}$, Arundinella hirta $T_{ANAKA}$ var. ciliata $K_{OIDSUMI}$, Ischaemum anthephoroides $M_{IQ}$. var. eriostachyum $H_{ONDA}$, and Phleum pretense L. grew in Medium D by submerged culture. 2) When the strain of the ergot of Agropyron semicostatum was inoculated into six different nutrient solutions for submerged culture, its mycelium grew well in Media C, D and F, but produced alkaloids only in Medium C, indicating that Medium C is relatively suitable for the strain. 3) The extraction of the alkaloids from the culture broth by ether and T.L.C. analysis of the extract showed that it contained at least two types of alkaloids.

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Occurrence of OF494911 in the Fungal Mat formed by Surface Culture of Aspergillus niger F-580

  • Chun, Hyo-Kon;Chung, Myung-Chul;Ko, Hack-Ryong;Lee, Ho-Jae;Kho, Yung-Hee
    • Journal of Microbiology and Biotechnology
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    • v.5 no.5
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    • pp.280-284
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    • 1995
  • Aspergi11us niger F-580, a potent producer of aminopeptidase M inhibitor, was isolated from the brown spots of plant leaves with a pathological trait. The inhibitory activity was found only in the fungal mat formed by surface culture of Aspergi11us niger F-580, but not in the culture supernatant or cell pellet. The inhibitor was purified from the hot water extract of this fungal mat by using chromatographies on Diaion HP-20, DEAE-cellulose, Sephadex G-l0 and YMC-ODS-AQ columns. The purified inhibitor was analyzed by UV, mass, and NMR spectroscopies, and identified as OF494911, which had been isolated as an aminopeptidase B inhibitor from Penicillium rugulosum OF4949

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Modeling of Typical Microbial Cell Growth in Batch Culture

  • Jianqiang Lin;Lee, Sang-Mok;Lee, Ho-Joon;Koo, Yoon-Mo
    • Biotechnology and Bioprocess Engineering:BBE
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    • v.5 no.5
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    • pp.382-385
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    • 2000
  • A mathematical model was developed, based on the time dependent changes of the specific growth rate, for prediction of the typical microbial cell growth in batch cultures. This model could predict both the lag growth phase and the stationary growth phase of batch cultures, and it was tested with the batch growth of Trichoderma reesei and Lactobacillus delbrueckii.

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Optimization of the Performance of Microbial Fuel Cells Containing Alkalophilic Bacillus sp.

  • CHOI, YOUNGJIN;JOOYOUNG SONG;SEUNHO JUNG;SUNGHYUN KIM
    • Journal of Microbiology and Biotechnology
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    • v.11 no.5
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    • pp.863-869
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    • 2001
  • A systematic study of microbial fuel cells comprised of alkalophilic Bacillus sp. B-31 has been carried out under various operating conditions. A significant amount of electricity was generated when redox mediators were used. Among the phenothiazine-type redox dyes tested, azure A was found to be the most effective both in maintaining a high cell voltage and for the long-term operation. The maximum efficiency was and for the long-term operation. The maximum efficiency was obtained at ca. $50^{\circ}C$ giving an open circuit voltage of 0.7V. A small change in temperature did not significantly affect the cell performance, but a rapid decrease in performance was observed below $20^{\circ}C$ and above $70^{\circ}C$. It was noticeable that fuel cell efficiency and discharge pattern depended strongly on the carbon source used in the initial culture medium. Regardless of the initial carbon sources, only glucose and trehalose were utilized as substrates. Galactose, however, was not substantially utilized except when galactose was used in the initial medium. Glucose, in particular, showed $87\%$ coulombic efficiency, which was the highest value ever reported, when Bacillus sp. was cultured in a maltose-containing medium. This study demonstrates that highly efficient microbial fuel cells can be constructed with alkalophilic microorganisms by fine-tuning the operating conditions and by carefully selecting carbon sources in the initial culture medium.

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Expression and Secretion of Human Serum Albumin in the Yeast Saccharomyces cerevisae

  • Kang, Hyun-Ah;Jung, Moon-Soo;Hong, Won-Kyoung;Sohn, Jung-Hoon;Choi, Eui-Sung;Rhee, Sang-Ki
    • Journal of Microbiology and Biotechnology
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    • v.8 no.1
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    • pp.42-48
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    • 1998
  • In order to maximize the secretory expression of human serum albumin (HSA) in the yeast Saccharomyces cerevisiae, a series of HSA expression vectors were constructed with a combination of different promoters, 5' untranslated regions (5'UTR), and secretion signal sequences. The expression vector composed of the galactose-inducible promoter GALl0, the natural 5'UTR, and the natural signal sequence of HSA directed the most efficient expression and secretion of HSA among the constructed vectors when introduced into several S. cerevisiae strains. Although the major form of HSA expressed and secreted in the yeast transformants was the mature form of 66 kDa, the truncated form of 45 kDa was also detected both in the cell extract and in the culture supernatant. The level of the intact HSA protein in the culture supernatant reached up to 30 mg/l at 24 h of cultivation in a shake-flask culture but began to decrease afterwards, indicating that the secreted HSA protein was unstable in a prolonged culture of yeast.

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