• Journal of Microbiology and Biotechnology
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• v.21 no.9
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• pp.968-971
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• 2011

Leuconostoc genus, which comprise heterofermentative lactic acid bacteria, reduces fructose to mannitol by recycling intracellular NADH. To evaluate the mannitol productivities of different Leuconostoc species, 5 stock cultures and 4 newly isolated strains were cultivated in MRS and simplified media containing glucose and fructose (1:2 ratio). Among them, L. citreum KACC 91348P, which was isolated from kimchi, showed superior result in cell growth rate, mannitol production rate, and yield in both media. The optimal condition for mannitol production of this strain was pH 6.5 and $30^{\circ}C$. When L. citreum KACC was cultured in simplified medium in a 2 l batch fermenter under optimal conditions, the maximum volumetric productivity was 14.83 $g{\cdot}l^{-1}h^{-1}$ and overall yield was 86.6%. This strain is a novel and efficient mannitol producer originated from foods to be used for fermentation of fructose-containing foods.

• Journal of the Korean Society of Food Science and Nutrition
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• v.19 no.6
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• pp.641-645
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• 1990

In order to study the influence of culture conditions on cell growth and lipid formation by Mucor sp, various carbon and nitrogen sources initial pH and C./N ratio of medium were investigated. Glucose was found to be suitable carbon source in terms of lipid yield and ${\gamma}$-linolenic acid(GLA) content. When NH4Cl and (NH4)2SO4 were used as nitrogen source lipid content was high(19-21%) but GLA content was low(15-17%) On the other hand when NaNO3 and KNO3 were used lipid content was low(about 13%) but GLA content was high(22-23%). The highest production of lipid was obtained at a C/N ratio of 40 using glucose and (NH4)2SO4 as carbon and nitrogen source respectively. it was found that lipid yield was high at pH4.6 Also this fungus did not grow at 35$^{\circ}C$ and lipid yield was highr at 15$^{\circ}C$ than $25^{\circ}C$.

• The Korean Journal of Physiology and Pharmacology
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• v.19 no.1
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• pp.35-42
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• 2015

In cardiovascular disorders, understanding of endothelial cell (EC) function is essential to elucidate the disease mechanism. Although the mouse model has many advantages for in vivo and in vitro research, efficient procedures for the isolation and propagation of primary mouse EC have been problematic. We describe a high yield process for isolation and in vitro culture of primary EC from mouse arteries (aorta, braches of superior mesenteric artery, and cerebral arteries from the circle of Willis). Mouse arteries were carefully dissected without damage under a light microscope, and small pieces of the vessels were transferred on/in a Matrigel matrix enriched with endothelial growth supplement. Primary cells that proliferated in Matrigel were propagated in advanced DMEM with fetal calf serum or platelet-derived serum, EC growth supplement, and heparin. To improve the purity of the cell culture, we applied shearing stress and anti-fibroblast antibody. EC were characterized by a monolayer cobble stone appearance, positive staining with acetylated low density lipoprotein labeled with 1,1'-dioctadecyl-3,3,3',3'-tetramethyl-indocarbocyanine perchlorate, RT-PCR using primers for von-Willebrand factor, and determination of the protein level endothelial nitric oxide synthase. Our simple, efficient method would facilitate in vitro functional investigations of EC from mouse vessels.

• Microbiology and Biotechnology Letters
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• v.26 no.3
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• pp.244-249
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• 1998

An extracellular polysaccharide, methylan, was produced under the specific conditions by Methylobacterium organophilum from methanol. The specific growth rate of cells was approximately constant regardless of C/N ratio and the specific product yield was maximum at a C/N ratio of 30. Methylan production was suppressed by the deficiency of mineral ions such as Mn$^{++}$ or Fe$^{++}$ ion. The optimal pH for cell growth and methylan production was 7. Whereas the optimal temperature for cell growth was found to be 37$^{\circ}C$, that for methylan production was 3$0^{\circ}C$. The methanol concentration above 4% completely inhibited the cell growth. The initial methanol concentration for the maximal production of methylan was 0.5% (v/v) and above this concentration, methylan production was markedly inhibited. To overcome the substrate toxicity and inhibition for both cell growth and methylan production, a fed-bach culture of intermittent feeding within 5 g/l methanol was conducted under the optimal culture condition. Methylan production of was stimulated by nitrogen limitation and methylan was accumulated up to 8.7 g/1 and cell mass also increased up to 12.4 g/l.

• Journal of Microbiology and Biotechnology
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• v.25 no.3
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• pp.358-365
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• 2015

ε-Poly-L-lysine (ε-PL) is a homopolymer of L-lysine molecules connected between the epsilon amino and alpha carboxyl groups. This polymer is currently used as a natural preservative in food. Insufficient biomass is a major problem in ε-PL fermentation. Here, to improve cell growth and ε-PL productivity, various nitrogen-rich nutrients were supplemented into flask cultures after 16 h cultivation, marking the onset of ε-PL biosynthesis. Yeast extract, soybean powder, corn powder, and beef extract significantly improved cell growth. In terms of ε-PL productivity, yeast extract at 0.5% (w/v) gave the maximum yield (2.24 g/l), 115.4% higher than the control (1.04 g/l), followed by soybean powder (1.86 g/l) at 1% (w/v) and corn powder (1.72 g/l) at 1% (w/v). However, supplementation with beef extract inhibited ε-PL production. The optimal time for supplementation for all nutrients examined was at 16 h cultivation. The kinetics of yeast-extract-supplemented cultures showed enhanced cell growth and production duration. Thus, the most commonly used two-stage pH control fed-batch fermentation method was modified by omitting the pH 5.0-controlled period, and coupling the procedure with nutrient feeding in the pH 3.9-controlled phase. Using this process, by continuously feeding 0.5 g/h of yeast extract, soybean powder, or corn powder into cultures in a 30 L fermenter, the final ε-PL titer reached 28.2 g/l, 23.7 g/l, and 21.4 g/l, respectively, 91.8%, 61.2%, and 45.6% higher than that of the control (14.7 g/l). This describes a promising option for the mass production of ε-PL.

• 한국생물공학회:학술대회논문집
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• 2002.04a
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• pp.419-422
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• 2002

Fermentative hydrogen production by Citrobacter sp. Y 19 was investigated in batch culture. Optimal hydrogen production activity was observed at pH 6 - 7 and temperature of $36^{\circ}C$, and hydrogen yield and maximal hydrogen production rate were 1.12 mmol/mmol glucose and 32.3 mmol/g cell${\cdot}$h, respectively. With glucose as a substrate, the bacterium produced ethanol, acetate, and carbon dioxide as major glucose fermentation by-products. Y19 could utilize various sugars such as galactose, fructose, lactose, sucrose, and starch for cell growth and hydrogen production.

• Journal of Applied Biological Chemistry
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• v.50 no.3
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• pp.132-135
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• 2007

An efficient production method of chlorella extract was developed by enzymatic treatment using cell lytic and proteolytic enzymes. The suitable dosage of Tunicase, a cell lytic enzyme, was found to be 1.0% (w/w). Proteolytic enzymes were screened to obtain high chlorella growth factor (CGF) index, which indicates crude CGF content and solid recovery. Among the seven tested proteases, Esperase, whose optimal dosage was 1.0% (w/w), was selected. By co-treatment using optimal dosages of Tunicase and Esperase, the highest CGF index and solid recovery were obtained. The CGF index and solid recovery of co-treatment were remarkably enhanced by 250 ($4.36{\rightarrow}15.21$) and 220% ($12.65%{\rightarrow}40.15%$), respectively, than those of the non-treated extracts.

• Journal of Plant Biotechnology
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• v.1 no.1
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• pp.1-7
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• 1999

Large-scale cultures of plant cell, tissue, and organ have been achieved by using BTBB. When different sized BTBBs (5 L, 20 L, 100 L, 300 L, and 500 L) were tested for the culture of yew cells (Taxus cuspidata Sieb. et Zucc.), cell growth increment reached to 94.5% in SCV after 24 days of culture with 30% of inoculation cell density. However, there were some variations in the production of taxol and its derivatives among the BTBBs of different size. Approximate 4 ㎎/l of taxol and 84 ㎎/l of total taxanes were obtained by using a 500L BTBB after 6 weeks of culture. With a 20L BTBB, about 20,000 cuttings of virus-free potatoes (cv. Dejima) could be obtained by inoculating 128 explants and maintaining 8 weeks under 16 hr light illumination. The frequency of ex vitro rooting of the cuttings revealed as more than 99% under 30% shade. By incorporating two-stage culture process consisting of multiple bulblet formation in solid medium and bulblet development in liquid medium, mass propagation of lily through bioreactor seemed to be possible. In the case of 'Marcopolo', the growth of mini-bulblets in BTBB was nearly 10 folds faster than that of the solid medium. Time course study revealed that maximum MAR yield of ginseng (Panax ginseng C. A. Meyer) in a 5 L and 20 L BTBB after 8 weeks of culture was 500 g and 2.2 ㎏, respectively. By cutting the MAR once and/or twice during the culture, the yield of root biomass could be increased more than 50% in fresh weight at the time of harvest. With initial inoculum of 500 g of sliced MAR in a 500 L BTBB, 74.8 ㎏ of adventitious root mass was obtained after 8 weeks of culture. The average content of total ginseng saponin obtained from small-scale and/or pilotscale BTBBs was approximately 1% per gram dry weight. Based on our results, we suggest that large-scale cultures of plant cell, tissue, and organ using BTBB system should be quite a feasible approach when compared with conventional method of tissue culture.

• Proceedings of the Korean Society of Embryo Transfer Conference
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• 2003.10a
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• pp.102-102
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• 2003

• Journal of Microbiology and Biotechnology
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• v.30 no.1
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• pp.109-117
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• 2020

Cre recombinase is widely used to manipulate DNA sequences for both in vitro and in vivo research. Attachment of a trans-activator of transcription (TAT) sequence to Cre allows TAT-Cre to penetrate the cell membrane, and the addition of a nuclear localization signal (NLS) helps the enzyme to translocate into the nucleus. Since the yield of recombinant TAT-Cre is limited by formation of inclusion bodies, we hypothesized that the positively charged arginine-rich TAT sequence causes the inclusion body formation, whereas its neutralization by the addition of a negatively charged sequence improves solubility of the protein. To prove this, we neutralized the positively charged TAT sequence by proximally attaching a negatively charged poly-glutamate (E12) sequence. We found that the E12 tag improved the solubility and yield of E12-TAT-NLS-Cre (E12-TAT-Cre) compared with those of TAT-NLS-Cre (TAT-Cre) when expressed in E. coli. Furthermore, the growth of cells expressing E12-TAT-Cre was increased compared with that of the cells expressing TAT-Cre. Efficacy of the purified TAT-Cre was confirmed by a recombination test on a floxed plasmid in a cell-free system and 293 FT cells. Taken together, our results suggest that attachment of the E12 sequence to TAT-Cre improves its solubility during expression in E. coli (possibly by neutralizing the ionic-charge effects of the TAT sequence) and consequently increases the yield. This method can be applied to the production of transducible proteins for research and therapeutic purposes.