• Applied Biological Chemistry
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• v.38 no.1
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• pp.20-25
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• 1995

This experiment was attempted to improve ethanol productivity by immobilization of Kluyveromyces marxianus FO43 using Jerusalem artichoke powder. Sucrose medium was used to determine optimum conditions for cell immobilization. The optimum conditions were alginate concentration of 2%, bead size of 2 mm, a particle input ratio of 30 : 100, cultivation period of 24 hours, and substrate concentration of 10%(w/v). The immobilized cells produced the high concentrations of ethanol at pH $4.5{\sim}6.5$ and $30{\sim}45^{\circ}C$, broader ranges of pH and temperatures than those of free cells. Under optimum conditions the immobilized cells showed ethanol concentration of 46.4 g/L and productivity of 1.93 g/L.h. The microphotograph using a two phase contrast microscope showed that immobilized cells cultivated under the optimum conditions were densely populated toward the surface area of beads.

• Korean Journal of Food Science and Technology
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• v.23 no.2
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• pp.167-174
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• 1991

Cultural conditions for the biopolymer production by an alkali tolerant Bacillus sp. isolated from soil were investigated and determination of optimal conditions was carried out by response surface method. The maximal production of biopolymer was obtained after cultivation at $30^{\circ}C$ for 36hrs in the mixture of 8% soluble starch, 0.75% yeast extract, 0.1% $NaNO_3$, 0.05% $MgSO_4\;7H_2O$ and 1% $Na_2CO_3$ adjusted to pH 10. Under these conditions, about 44 g/l of biopolymer were produced. From the results of response surface analysis, optimal condition for the production of biopolymer were obtained at stationary point with 15.16 of C/N ratio, $34.62^{\circ}C$ of temperature and 9.50 of pH. On the basis of these conditions, it was estimated that 66.84 g/l of the biopolymer could be produced.

• Current Research on Agriculture and Life Sciences
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• v.28
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• pp.31-38
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• 2010

Extraction efficiency of colorants from red bean and black bean seed coat and its storage stability were examined according to the various extracting and storage conditions in this study. The obtained results were as follows ; The absorbance values of extracted colorants were increased with increasing extract time and temperature. pH 4 extracting was most efficient among the various pH conditions. The absorbance values of extracted colorant from red bean were increased with increasing extract time and temperature, when the extraction process was kept at $30^{\circ}C$ and $50^{\circ}C$, but it were decreased with increasing extract time at $70^{\circ}C$. In the case of black bean, it were also increased with increasing extract time and temperature. pH 5 extract was most efficient among the various pH conditions. In juice extractor system from red bean, the pH 5 of the pre-treatment was more efficient than the distilled water of pre-treatment. In black beans of the short-term pre-treatment with distilled water, the colorant was extracted better than at pH 5, but above 4 hours pre-treatment was decrease in pH 5. The Methionine added as a stabilizer gave the more effect to the stability of colorant from red bean the more Methionine addition. In the case of black bean 10mmol addition of methionine was more efficient than 20mmol.

• Ocean and Polar Research
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• v.44 no.3
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• pp.209-220
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• 2022

Carbonic anhydrase (CA) is a key controller of the carbon concentrating mechanism (CCM), and is known to be affected by ambient pH and CO₂ compositions. Herein, we characterized three novel CAs genes (PmCA1, 2, and 3) from the marine dinoflagellate Prorocentrum minimum, and evaluated the relative expressions of the PmCAs and photosynthetic genes PmatpB and PmrbcL under different pH conditions. Each PmCA was predicted to have amino acid residues constituting the zinc binding site. With signal peptide, PmCA1 and PmCA2 were predicted to be intracellular CAs located in the cytoplasm and chloroplast membrane, respectively. On the other hand, PmCA3 was predicted to be extracellular CA located in the plasma membrane. Also, PmCA1 was classified into the beta family, and PmCA2 and PmCA3 were classified into the alpha family via phylogenic analysis. The photosynthesis efficiency of P. minimum was similar at pH 7 to 9, and decreased significantly at pH 6 and pH 10. Overall, relative gene expression levels of the three PmCAs decreased at low pH, and increased as pH increased. Photosynthesis related genes, PmatpB and PmrbcL, showed similar expression patterns to those of PmCAs. These results suggest that changes in seawater pH may affect photosynthesis and CO₂ metabolism in marine dinoflagellates.

• KSBB Journal
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• v.15 no.4
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• pp.405-407
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• 2000

A novel recovery method was developed to obtain the plant cell and its debris from Taxus chinensis cell cultures By pH control of plant cell cultures plant cell and debris was precipitated. The best pH is between 1.8 and 2.2 to obtain the precipitate of the plant cell and debris. Also paclitaxel is stable in this acidic conditions. This method is very simple an efficient to recover the plant cell and debris from plant cell cultures.

• Journal of Korean Society of Water and Wastewater
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• v.24 no.4
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• pp.463-474
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• 2010

In this study, chemical coagulation conditions for treating combined sewer overflow(CSO) occurred during rainy season were evaluated by jar tests with aluminum sulfate[$Al_2(SO_4)_3{\cdot}17H_2O$] and ferric chloride[$FeCl_3{\cdot}6H_2O$]. The raw domestic sewage sampled from the primary sedimentation tank at a local sewage treatment plant was filtered through $150{\mu}m$ sieve before using. Point of zero charge(PZC) for various dose of aluminum sulfate occurred at pH 5.8-6.5, while for ferric chloride occurred at pH 5.3-6.0 in term of streaming current(SC) values. Charge neutralization ability of aluminum sulfate was bigger than that of ferric chloride. Optimum pH and dose of aluminum sulfate and ferric chloride were 6.2, 0.438mM and 5.8, 0.925mM, respectively. Removal efficiencies of TCOD, turbidity, SS and TP were 75, 97, 95, 96% with aluminum sulfate and 74, 96, 98, 99% with ferric chloride at their optimum coagulation conditions. More efficient removal of SS, TP and small particles was possible with ferric chloride at optimum coagulation conditions. Both SC values and COD removal started to increase where soluble phosphorus was completely removed.

• The Korean Journal of Food And Nutrition
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• v.8 no.3
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• pp.192-198
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• 1995

For the production of EMC, various professes and lipases were used to hydrolyse cheese sulk. The optimal conditions of various proteases were as follows, pronase-3$0^{\circ}C$, p14 7.0, pancreatln-4$0^{\circ}C$, pH 8.0, pacific protease-3$0^{\circ}C$, pH 7.0 and protease from Asp. sp. -5$0^{\circ}C$, pH 8.0. The optimal conditions of various lipases were as follows ; pancreatic lipase-5$0^{\circ}C$, pH 8.0, palatase ML-5$0^{\circ}C$, pH 7.0 and lipase form Candida -4$0^{\circ}C$, pH U.0. After hydrolysation under optimal conditions, the amounts of free amino acid and free fatty ac14 were increased with reaction time. Hydrolysates of pacific protease and pronase were showed high amount of free amino acid(0.67mg/ml and 0.74mg/ml). Especially EMC had high amount of glutamic acid and leucine. Lipase from Candida cylindracea produced high amount of free fatty acid (24.63 mg/ml) Butyric acrid, palmitic acid, stearic acid and oleic acid among free fatty acids were showed high amounts. Sensory evaluation of various MC were tasted nth 8 panelist. EMC produced with pancreatic lipase was most bitterness and EMC produced with palatase ML was best acceptable cheese flavor.

• Journal of Microbiology and Biotechnology
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• v.27 no.3
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• pp.450-459
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• 2017

This study evaluated the effects of culture conditions, including carbon and nitrogen sources, L-monosodium glutamate (MSG), and initial pH, on gamma-aminobutyric acid (GABA) production by Lactobacillus brevis HYE1 isolated from kimchi, a Korean traditional fermented food. L. brevis HYE1 was screened by the production analysis of GABA and genetic analysis of the glutamate decarboxylase gene, resulting in 14.64 mM GABA after 48 h of cultivation in MRS medium containing 1% (w/v) MSG. In order to increase GABA production by L. brevis HYE1, the effects of carbon and nitrogen sources on GABA production were preliminarily investigated via one-factor-at-a-time optimization strategy. As the results, 2% maltose and 3% tryptone were determined to produce 17.93 mM GABA in modified MRS medium with 1% (w/v) MSG. In addition, the optimal MSG concentration and initial pH were determined to be 1% and 5.0, respectively, resulting in production of 18.97 mM GABA. Thereafter, response surface methodology (RSM) was applied to determine the optimal conditions of the above four factors. The results indicate that pH was the most significant factor for GABA production. The optimal culture conditions for maximum GABA production were also determined to be 2.14% (w/v) maltose, 4.01% (w/v) tryptone, 2.38% (w/v) MSG, and an initial pH of 4.74. In these conditions, GABA production by L. brevis HYE1 was predicted to be 21.44 mM using the RSM model. The experiment was performed under these optimized conditions, resulting in GABA production of 18.76 mM. These results show that the predicted and experimental values of GABA production are in good agreement.

• Journal of Sensor Science and Technology
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• v.20 no.4
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• pp.234-237
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• 2011

This paper presents a study into pH Indicator-Embedded hydrogel micro-particles which are encoded various shapes according to the captured indicator. We incorporate various pH indicators into a photo-curable hydrogel, PEG-DA(Poly(ethylene glycol) diacrylate). Using the latest fluidic lithography techniques, we can easily fabricate variously patterned hydrogel particles based on in-situ photopolymerization of the PEG-DA in a micro-fluidic channel. The shape of the particle is related to the pH indicator inside the particle. We demonstrate that the micro pH sensors change their colors according to the pH levels. The micro pH sensors have various characteristics that are related to the curing time, particle size, etc. By changing these conditions, we can adjust the long term stability and reaction time of the hybrid micro pH sensors.

• The Korean Journal of Mycology
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• v.32 no.2
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• pp.134-137
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• 2004

This study was carried out to determine the optimum culture conditions for Phellinus spp. known as white rot fungi showing anti-cancer activity. The optimum solid medium for mycelial growth at $25^{\circ}C$ was potato dextrose agar medium and optimum pH range was $6.0{\sim}8.0$, while all species showed reduced or no growth at pH 4.0. Most species showed good growth at $25{\sim}30^{\circ}C$. Out of 10 species of Phellinus examined, P. biscuspidatus was the best growing fungus in the range of pH $6.0{\sim}7.0$ based on mycelial density. Three species such as P. biscuspidatus, P. johnsonianus and P. lloydii could be grouped in mesophile fungi, showing $30{\sim}35^{\circ}C$ optimum temperature.