• 한국환경과학회지
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• 제21권10호
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• pp.1255-1263
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• 2012

Batch cultivations were performed to evaluate the influences of the initial pH condition on mesophilic and thermophilic acidogenic fermentation with food waste recycling wastewater. In both conditions of mesophilic and thermophilic fermentation, TVFAs production rates were maximized at the initial pH 7 condition as 0.15 and 0.23 g TVFAs/L hr, respectively. And pH was also maintained stably between 6 and 7 during 72hr acidogenic cultivation at both conditions. However, predominant VFA components were different according to reaction temperature conditions. In mesophilic condition, propionic acid which has low conversion efficiency to methane was accumulated up to 1,348 mg/L while acetic and butyric acid were predominant in thermophilic condition. Therefore, thermophilic acidogenic fermentation was superior for the effective VFAs production than mesophilic condition. From the DGGE analysis, the band patterns were different according to the initial pH conditions but the correlations of the each band were increased in similar pH conditions. These results mean that microbial communities were certainly affected by the initial pH condition. Consequently, the adjustment of the initial pH to neutral region and thermophilic operation are needed to enhance acidogenic fermentation of food waste recycling wastewater.

• 한국식품저장유통학회지
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• 제22권2호
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• pp.256-260
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• 2015

본 연구에서는 알칼리 사용에 따른 갈변을 최소화하고 영양적으로 우수한 천마 단백질을 보다 효율적으로 추출하기 위하여 용출 및 침전 pH에 따른 단백질의 갈변도와 함량을 측정함으로써 탈지 천마 단백질 알칼리 추출의 최적 pH 조건을 설정하고자 하였다. 천마의 수분은 약 15%로 측정되었으며, 대부분 탄수화물로 구성되어 있었고, 단백질의 함량이 높은 것으로 확인되었다. 이러한 단백질을 다양한 pH에서 용출시킨 결과 pH가 증가함에 따라 용출된 단백질의 양이 증가하였으며, 갈변도 또한 증가함을 보였다. 침전 pH에 따른 단백질 함량은 pH 4에서 침전된 pellet이 가장 많은 함량을 나타내었으며, 상등액의 단백질 함량 또한 대부분 pH 4로 침전시킨 경우 가장 적은 것으로 확인되었다. 뿐만 아니라 단백질의 회수율도 침전 pH가 4일 때 가장 높은 값을 나타내었다. 따라서 갈변도와 단백질 함량을 고려한 탈지 천마 단백질 추출을 위한 최적조건은 용출 pH 9와 침전 pH 4로 결정되었다.

• Journal of Microbiology and Biotechnology
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• 제14권3호
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• pp.639-642
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• 2004

The pH as a control parameter for oxidation-reduction potential (ORP) was investigated through the denitrification by Ochrobactrum anthropi SY509 under non-growing condition. The optimal pH of nitrate reductase was 7.0, and the minimal ORP level was －250 mV for the denitrification under aerobic condition. In the case of anaerobic condition, the optimal pHs of nitrate and nitrite reductase were shifted to 10.0 and 9.0, respectively, and the minimal ORP levels of nitrate and nitrite reductase were decreased to －370 mV and －340mV, respectively. In the case of alkaline pH and anaerobic condition, the denitrification efficiency of nitrate was increased up to about 2-fold over that of neutral pH and anaerobic condition. Therefore, the combined control of pH and ORP in the anaerobic condition is shown to be an important parameter in the biological denitrification process.

• KSBB Journal
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• 제4권2호
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• pp.65-68
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• 1989

누에 번데기의 단백질 추출 조건을 규명하고자 온도, ph및 시간 변화에 따라 추출된 단백질의 총 질소함량을 Kjeldahl법과 원소 분석기를 이용한 결과는 다음과 같다. 1. 누에 번데기의 초단백질 : 23.34%, 조지방 : 15.61%이나, 2. 온도 변화에 따른 ph 4에서 1시간 추출시 6$0^{\circ}C$:6.76%, 8$0^{\circ}C$:7.94%, 10$0^{\circ}C$:8.67%이고 C.H.N corder의 분석결과는 6$0^{\circ}C$:8.08%, 8$0^{\circ}C$:9.52%, 10$0^{\circ}C$:9.72%로서 두 가지 방법에서 수치는 다르지만 온도 상승에 따라 수용성 질소계수가 증가하는 경향임을 알 수 있다. 3. pH변화에 따른 8$0^{\circ}C$에서 1시간 추출시 pH 4:7.94%, pH 6:8.96%, pH : 8:9.70%, pH : 10:10.67%, pH : 12:10.98%로 온도 상승과 같이 pH증가에 따라 증가하는 경향을 보이고 있다. 4.추출시간의 변화에 따른 10$0^{\circ}C$에서 pH 4인경우 1시간:8.67%, 2시간:9.23%, 3시간:9.76%이고, C.H.N. corder의 결과는 1시간:9.72%, 2시간:10.06%, 3시간:10.83%로서 추출 시간이 늘어남에 따라 증가되는 경향을 보이고 있다.

• 미생물학회지
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• 제29권6호
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• pp.387-391
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• 1991

Methylobacterium extorquens AM1 growing on methanol as a sole source of carbon and energy was found to grow most rapidly (t$t_{d}$ =6h) at 30.deg.C in a mineral medium (pH 7.0) containing 0.5% (v/v) methanol which was agitated at 200 rpm (optimal cultivation condition). Cells grown under the optimal cultivation condition contained more spermidine, but less putrescine, than the cells grown on 2.5%(v/v) ( $t_{d}$ =8h ) or at 20.deg.C ( $t_{d}$ =8h ). Cells cultivated under the optimal condition was found to contain more spermidine than the cells grown at pH 6.0 (( $t_{d}$ =7h ) and pH 8.0 ($t_{d}$ =7.3h). the cells growing at the stationary phase under the optimal condition accumulated more spermine or putrescine than the cells growing at the same phase on 2.5%(v/v) methanol or at pH 6.0 and pH 8.0, respectively. M. extorquens AM1 grown in a medium agitated at 100 rpm ( $t_{d}$ =8.8h ) contained less spermidine and spermine than the cells grown under the optimal cultivation condition.

• 한국산학기술학회:학술대회논문집
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• 한국산학기술학회 2009년도 추계학술발표논문집
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• pp.100-102
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• 2009

Effect of temperature, pH and soil depth on germination of Dianthus chinensis, Dianthus barbatus, and Perennial pennant were investigated in growth chamber and soil condition at the ratio of 7:3 (natural soil and organic soil) in laboratory condition. the optimum temperature for seed germination was recorded for $20^{\circ}C-\;25^{\circ}C$. Maximum germination was observed for Dianthus barbatus (76%) where as in soil condition Perennial pennant (51%) showed maximum germination at 1 cm soil depth. Similarly, optimum pH for seed germination was at pH 6 in all the species. So in lower pH (at pH4) seed germination was inhibited. Germination of these selected species at different environmental condition help to construct the ecological sound proof wall to mitigate the noise especially in urban areas.

• 한국생물공학회:학술대회논문집
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• 한국생물공학회 2002년도 생물공학의 동향 (X)
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• pp.211-214
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• 2002

The optimal condition for the production of DXAMase, containing the both characteristics of dextranase and amylase, was studied based on different levels of pH, temperature, and aeration rate. Response surface methodology was applied to find the optimatic condition showing the relationship between the fermentation response(dextranase and amylase activity of DXAMase) and the fermentation variables(pH, temperature, and agitation rate). In case of dextranase activity, the condition of pH 4.06, $28.08^{\circ}C$, and 235.14 rpm showed the highest activity, 2.26 U/ml, and for amylase activity, the condition of pH 4.01, $27.96^{\circ}C$, and 212.01 rpm showed the highest activity, 3.52 U/ml. For the production of DXAMase, dextranase and amylase, the optimum condition was pH 4.06, $28.08^{\circ}C$, and 234.80 rpm.

• 패션비즈니스
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• 제11권2호
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• pp.102-112
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• 2007

Effect of the pH condition was examined on extraction and dyeing of the yellow and red dyes of safflower. Absorption of dye solution extracted from safflower was changed by pH of solvent. In the case of yellow dyes, cotton and ramie weren't dyed regardless of pH of dye bath, but silks were significantly dyed at pH4. Raw silk showed better dyeability than refined silk. In the case of red dyes, cotton and ramie absorbed red dyes selectively, but silks absorbed yellow dyes more significantly than red dyes. Efficiency of extraction and dyeing of yellow dyes in acidic range were find out higher than that in neutral range. Red dyes was effectively extracted at pH11 and dyed at pH6.

• 한국미생물·생명공학회지
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• 제23권4호
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• pp.373-377
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• 1995

We investigated the survival, $\beta$-galactosidase activity and cellular permeability of lactic acid bacteria such as Lactobacillus acidophilus ATCC 4356, Lactobacillus casei subsp. casei IFO 3533, Streptococcus thermophilus KCTC 2185, Lactobacillus delbrueckii subsp. lactis ATCC 4797, and Lactobacillus delbrueckii subsp. bulgaricus ATCC 11842 in anaerobic condition of pH 1.5-3.5 range. Numbers of all tested viable cells did not decrease at pH 3.5, but decreased rapidly at pH 1.5 and pH 2.5 during 2 hour incubation at modified EG medium. Immediately after 2 hour incubation, the decrease in population at pH 1.5 and pH 2.5 was about 6-8 and 5-7 log cycles/ml, respectively. Lactobacillus acidophilus ATCC 4356 showed the higest survival of all tested bacteria. The $\beta$-galactosidase activity from Lactobacillus delbrueckii subsp. bulgaricus ATCC 11842 and Streptococcus thermophilus KCTC 2185 decreased rapidly at pH 1.5 and 2.5, but there was a little decrease at pH 3.5. The cellular permeability that was measured by the leakage of intracellular materials increased with decrease of pH. These results suggest that the ingested lactic acid bacteria may be destroyed in contact with low pH of gastric acid.

• 한국환경과학회지
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• 제11권10호
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• pp.1103-1108
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• 2002

In order to evaluate the degradation organophosphorus pesticide, EPN, in water environment, the effects of water temp.(10$^{circ}C,\;30^{\circ}C$), pH(3-11) and sunlight on its degradation were investigated during 10 days. The degradation rate of EPN(200 rpm) was faster at higher water temp. and higher pH, i.e., its degradation rate at pH 3, 5, 7, 9, 11 was 57, 63, 66, 69, 75%(1$0^{\circ}C$), and 70, 74, 79, 91, 97%(3$0^{\circ}C$) after 10 days, respectively. The effect of water temp. on its degradation was little in acidic condition, but was rather great in alkaline condition, with time. EPN was degraded fast at the alkaline condition by photolysis. At the condition of pH 11, EPN was degraded fast at the early stage in the first 2 days, but after that the degradation rate was weakened.