• Food Science and Biotechnology
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• 제18권4호
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• pp.954-958
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• 2009

Effects of controlled- and uncontrolled-pH operations on phenylalanine ammonia lyase (PAL) production by a recombinant Escherichia coli strain were investigated at uncontrolled-pH ($pH_{UC}$) and controlled-pH ($pH_C$) of 5.5, 6.0, 6.5, 7.0, 7.5, 8.0, and 8.5 in bioreactor systems. The results showed that the recombinant PAL activity was improved significantly by controlled pH strategy. Among the $pH_C$ operations, the highest PAL activities were obtained under $pH_C$ 7.5 strategy where cell mass ($OD_{600\;nm}$) and PAL activity was 1.3 and 1.8 fold higher than those of $pH_{UC}$, respectively. The maximum PAL activity reached 123 U/g. The $pH_C$ 7.5 strategy made recombinant plasmid more stable and therefore allowed easier expression of PAL recombinant plasmid, which increased PAL production. It was indicated that the new approach (controlled-pH strategy) obtained in this work possessed a high potential for the industrial production of PAL, especially in the biosynthesis of L-phenylalanine.

• Journal of Microbiology and Biotechnology
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• 제18권1호
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• pp.128-134
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• 2008

The kinetics of cell growth and Cyclosporin A (Cyc A) production by Tolypocladium inflatum were studied in shake flasks and bioreactors under controlled and uncontrolled pH conditions. In the case of the shake flask, the production time was extended to 226 h and the maximal antibiotic concentration was 76 mg/l. When scaling up the cultivation process to a bioreactor level, the production time was reduced to only 70h with a significant increase in both the cell growth and the antibiotic production. The maximal dry cell weights in the case of the controlled pH and uncontrolled pH cultures in the bioreactor were 22.4g/l and 14.2g/l, respectively. The corresponding maximal dry cell weight values did not exceed 7.25g/l with the shake flask cultures. The maximal values for Cyc A production were 144.72 and 131.4 mg/l for the controlled and uncontrolled pH cultures, respectively. It is also worth noting that a significant reduction was observed in both the dry cell mass and the antibiotic concentration after the Cyc A production phase, whereas the highest rate of antibiotic degradation was observed in the stirred tank bioreactor with an uncontrolled pH. Morphological characterization of the micromorphological cell growth (mycelial/pellet forms) was also performed during cultivation in the bioreactor.

• 한국가축번식학회지
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• 제21권1호
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• pp.25-30
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• 1997

This study was done to find out the preservation possibility of liquid boar semen at variabel room temperature of 9 to 16$^{\circ}C$. The percentages of sperm motility and NAR acrosome were highest in B tschwiler extender compared to B tschwiler＋Hepes, Andro＋Hepes and Andro extenders. The extenders with Hepes buffer showed detrimental effect for preservation of liquid boar semen. The pH of ejaculated sperm-rich fraction was 7.5. The pH of B tschwiler＋Hepes, B tschwiler, Andro＋Hepes and Andro extenders was 6.9, 7.5, 7.1 and 8.1, respectively. The pH of liquid boar semen with B tschwiler＋Hepes, B tschwiler, Andro＋Hepes and Andro extenders was 6.6, 6.9, 6.7 and 6.9 at 1st day of storage, and 5.5, 5.7, 5.6 and 5.8 at 7th day of storage, respectively. Gilts and sows were inseminated twice with liquid boar semen stored at 9~16$^{\circ}C$ in B tschwiler extender for 3~4 days. Farrowing rate, litter size and average pig weight at birth between AI and natural service did not differ significantly in gilt and sow, respectively. However, sow showed higher farrowing rate and litter size compared to gilt both in AI and in natural service. As a result of this study, we found out that liquid boar semen can be stored for 5~7 days at uncontrolled room temperature of 9~16$^{\circ}C$ in B tschwiler extender.

• KSBB Journal
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• 제16권2호
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• pp.207-211
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• 2001

Statistical experimental design methods were employed to select the cultivation factors influencing latic acid production during the fermentation of kitchen refuses. Working volume and pH swings were identified as the main factors affecting lactic acid production. Optimum pH swing was pH 7.8 and working volume was 125 mL in a 250 mL flask. Under optimum condition, lactic acid was produced at 21.8 g/L, which was 6.2 times higher than produced during uncontrolled fermentation.

• 산업기술연구
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• 제20권A호
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• pp.45-50
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• 2000

A submerged cultivation of Ganoderma lucidum was carried out in an air-lift fermenter system, and the effects of different pH processes on extracellular branched ${\beta}$-1,3-glucan(EPS) production and mycelial growth(MDW) were investigated. The controlled pH process improved the production of branched ${\beta}$-1,3-glucan and biomass in comparison to the uncontrolled pH process. However, the maximum production of branched ${\beta}$-1,3-glucan were obtained by the bi-staged pH process. From these results, we confirmed that the bi-staged pH process was the most effective for improving the production of branched ${\beta}$-1,3-glucan from submerged culture of G. lucidum.

• Nutrition Research and Practice
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• 제9권2호
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• pp.180-185
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• 2015

BACKGROUND/OBJECTIVES: The aims of the present study are: 1) to quantify sodium consumption of patients with unstable or uncontrolled hypertension, 2) to investigate if reduced sodium intake can lower BP in these patients, and 3), to assess the acceptability and feasibility of this approach. SUBJECTS/METHODS: This study included 25 adults (age: 50+ years) with frequently elevated BP or patients with uncontrolled, uncomplicated hypertension despite drug treatment in a general practice setting. BP and salt intake (24h urinary excretion and food records) were measured at baseline and after a sodium reduced diet. RESULTS: Mean (${\pm}SD$) systolic (SBP) over diastolic (DBP) blood pressure (mmHg) at baseline was $150.7({\pm}9.5)$/$84.149({\pm}5.6)$. Mean urinary sodium excretion was 146 mmol/24h. A reduction of 28 mmol sodium excretion decreased SBP/DBP to $135.5({\pm}13.0)$/$82.5({\pm}12.8)$ (P < 0.001). After one month of no dietary advice, only in 48%, SBP was still ${\leq}140mmHg$. CONCLUSION: Assessment of sodium intake using food records, 24h urine collections and probing questions to identify use of sodium containing supplements or drugs are essential for tailored advice targeted at sodium intake reduction. The results of the present study indicate that reduced sodium intake can lower BP after 4 weeks in unstable or uncontrolled hypertensive patients.

• KSBB Journal
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• 제13권5호
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• pp.511-517
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• 1998

Temperature and pH conditions were studied for an effective biosurfactant production by Pseudomonas aeruginosa YPJ-80. Efficient methods of biosurfactant separation were also investigated. pH-uncontrolled experiments at 35$^{\circ}C$ and an initial pH of 8 resulted in the best cell growth (3.6 g/L) and biosurfactant production (0.073 g biosurfactant/g cell). Biosurfactant separation was most efficient using solvent extraction with chloroform/methanol (2:1 vol%) followed by acidification using 1N HCl.

• Fisheries and Aquatic Sciences
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• 제11권4호
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• pp.219-223
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• 2008

To increase the level of $CoQ_{10}$ production in mass culture, the effects of pH and light irradiation on $CoQ_{10}$ production by Rhodobacter sphaeroides were investigated in a 1-L bioreactor. $CoQ_{10}$ production was growth-associated, and the highest production of $CoQ_{10}$ (1.69 mg/g dry cell) was obtained under uncontrolled pH: this production was 1.7 times higher than that obtained at controlled pH 7. Therefore, pH was a key factor affecting $CoQ_{10}$ production. The effect of light irradiation on $CoQ_{10}$ production was negligible. This result offers an advantage for mass production of $CoQ_{10}$.

• 해양환경안전학회지
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• 제22권5호
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• pp.490-499
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• 2016

본 연구는 해양에서 1차 소비자 단계인 윤충류 Brachionus plicatilis와 저서성 요각류 Tigriopus japonicus의 초기생활사에 미치는 탈인슬래그와 제강슬래그 추출액의 생태 영향을 평가하기 위하여 해양생태독성평가를 실시하였다. 슬래그 추출액에 대한 스크린 테스트 결과, 추출액의 pH는 높은 알칼리성(pH 8.89-12.16)이었으며, 숙성 전과 후 추출액에 대한 독성 반응은 실험생물에 따라 뚜렷하게 구분되었다. 숙성 전 슬래그의 경우, pH 비제어 시료에 대한 B. plicatilis 신생개체의 반수치사농도는 제강슬래그(63.8 %)가 탈인슬래그(20.8 %)보다 높은 것으로 나타났으며, T. japonicus 유생의 반수치사농도는 탈인슬래그와 제강슬래그에서 각각 35.3 %와 36.0 %로 비슷하였다. 그러나 pH를 제어한 경우, 숙성 전과 후 추출한 시료에 대한 T. japonicus 유생의 독성은 B. plicatilis 신생개체와는 다르게 노출물질 특성에 따라 뚜렷하게 구분되었다. 결론적으로 숙성 후 슬래그는 상대적으로 안정된 상태를 유지할 수 있으며, pH 비제어 환경조건 하에서도 반복 추출을 통해 해양환경에 미치는 영향이 적은 것으로 판단된다. 본 연구를 통해 슬래그와 같이 기계적으로 활성화 된 시료의 해양생태독성평가방법은 강우나 풍화로 인한 유해물질의 해양 유입을 차단할 수 있는 아이디어를 제공할 수 있을 것이다.

• Biotechnology and Bioprocess Engineering:BBE
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• 제7권6호
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• pp.331-334
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• 2002

Culture conductivity and on-line NADH fluorescence were used to measure cellular growth in plant cell suspension cultures of Podophyllum hexandrum. An inverse correlation between dry cell weight and medium conductivity was observed during shake flask cultivation. A linear relationship between dry cell weight and culture NADH fluorescence was obtained during the exponential phase of batch cultivation In a bioreactor under the pH stat (pH 6) conditions. It was observed that conductivity measurement were suitable for biomass characterisation under highly dynamic uncontrolled shake flask cultivation conditions. However, if the acid/alkali feeding is done for pH control the conductivity measurement could not be applied. On the other hand the NADH fluorescence measurement allowed online-in situ biomass monitoring of rather heterogenous plant cell suspension cultures in bioreactor even under the most desirable pH stat conditions.