• KSBB Journal
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• v.8 no.2
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• pp.164-171
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• 1993

The production of extracellular polysaccharide by Methylomonas mucosa (NRRL B-5696) was investigated. The microorganism uses methanol as the carbon source for their growth and produces exopolysaccharides. The productivity of exopolysaccharides was investigated under various culture modes: batch, fed-batch and continuous culture. In flask culture the growth of cell mass and the production of polysaccharide were inhibited at above 1% (v/v) methanol. At 1%(v/v) methanol maximum specific growth rate was obtained. As C/N ratio (g methanol/g ammonium sulfate) increased, polysaccharide production increased and cells mass decreased. Magnesium ion was also found to be essential for the polysaccharide production. In batch culture the production of polysaccharides was more affected by the specific growth rate than the cell concentration. In fed-batch culture the concentration of polysaccharide was 4 times higher than that of batch culture, but the yield was lower. The productivity of fed-batch with continuous feeding was higher than that of batch or fed-batch with intermittent feeding. This is due to no methanol limitation or inhibition that used to occur in fed-batch culture with intermittent feeding. In continuous culture pure oxygen was supplied to avoid the oxygen limitation. As the dilution rate in- creased up to 0.21 h-1, the yield and productivity increased. The solution viscosity of the produced polysaccharide obtained from above increased exponentially with the concentration of polysaccharide.

• Korean Journal of Ecology and Environment
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• v.42 no.2
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• pp.153-160
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• 2009

A phytoplankton cultivation system was installed and operated for removal of nutrients from stream water polluted by nonpoint source pollution. The system was a continuous-flow culture comprising a phytoplankton tank that received inflow from a storage reservoir. When the system was operated as a batch culture for the purpose of determining hydraulic retention time (HRT), the proper HRT value was three days, and the removal rate of TP and TN averaged 70% and 44%, respectively. When the system was operated with the continuous flow from a stream for 45 days, 53.9% of TP and 53.1% of TN were removed as sludge. Due to active growth of phytoplankton, pH and dissolved oxygen in the phytoplankton tank were extremely high, reaching 10.8 and 16mg $L^{-1}$, respectively. It was concluded that nutrients can be effectively removed from polluted stream waters by cultivating phytoplankton.

• Journal of Life Science
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• v.18 no.7
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• pp.980-985
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• 2008

This study was carried out to develope an alcoholic drink by fermentation of onion extract using Saccharomyces cerevisiae. The optimal conditions for ethanol production were obtained by standing culture at $25^{\circ}C$ for 5 days with 5% inoculum volume. At the results by flask culture, the growth curve of used S. cerevisiae reached to the stantionary phase at 48 hr and the death phase at 90 hr, whereas ethanol production reached maximum at 114 hr. Under the above conditions, a large scale production was carried out. A standing culture in 5 l fermenter showed the similar results to its flask culture, but progressed 24 hr rapidly more than that of the flask culture. A fed-batch culture was performed by addition of the onionic medium supplemented with 10% (v/v) sucrose after 72 hr from the fermenting start. The fed-batch culture could prevent S. cerevisiae from entering into the death phase and maintain constant level of alcohol production. A continuous culture was able to carry out by adding per every 24 hr the onionic medium supplemented with 10% (v/v) sucrose after 72 hr from the fermenting start. Although S. cerevisiae used showed a little decreased growth, alcohol production maintained roughly the constant level at the maximum yield. To enhance the quality of this alcoholic drink, $2-O-{\alpha}-D-glucopyranosyl$ L-ascorbic acid (AA-2G) was supplemented into the onion extract of the substrate for fermentation. As resulted at this study, this alcoholic drink containing AA-2G should be used as a functional fermented alcohol drink strengthened with vitamin C.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.14 no.2
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• pp.86-93
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• 1981

For daily supply of rotifers to feed juvenile fish and/or larval crustaceans such as shrimp in their seedling culture procedures, the maximum daily increase of cultured rotifers in relations with the inoculation densities of rotifers and the concentrations of food organism, Chlorella sp. were initially investigated in an experimental culture unit. The best results were obtained from the 10 inds./ml of the rotifer inoculation density with $3\times10^6\;cells/ml$ of Chlorella showing the maximum daily increase of 73.0 inds./ml/day on the 7th day. Based on the best results of the initial experiments a trial was made for continuous daily harvests of rotifers. As in the initial experiments, the maximum daily increase of rotifer was observed on the 7th day, when the daily harvest was initiated and continued once a day for 6days. For the 6 days, the amount of the mean daily harvest was $1.42\times10^5$ individuals per culture flask ($3{\iota}\;filled\;with\;2{\iota}$culture water) shelving a possibility of continuous daily harvests.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.15 no.3
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• pp.179-184
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• 1982

The behavior of continuous flow culture of Lartobacillus bulgricus was investigated by application of Monod's kinetic model. The parameters obtained from Monod's chemostat theory successfully predicted the behavior of the chemostat. Then, it was found that Monod's kinetics were applicable to the growth rate dependence on glucose concentration. Under steady-state condition, the maximum growth rate, saturation constant, and wash out were found to be 0.62/hr, 7.69 g/1, 0.51/hr of continuous culture. And the optimum condition for the highest cell production was 0.41/hr in dilution rate, and at that point the cell production rate was 0.178g/1 hr.

• Proceedings of the Korean Society for Bio-Environment Control Conference
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• 1997.05a
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• pp.17-22
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• 1997

본 연구에서는 고구마 조직배양묘의 $CO_2$ 교환량을 측정하기위해 개방형 광합성측정장치의 원리를 이용해 자체제작한 $CO_2$ 교환량 측정장치를 이용하여 공기 주입구와 배출구의 $CO_2$ 농도를 연속측정하고, 명기와 암기에 있어서의 $CO_2$ 교환량의 일변화를 분석했다. 내용적 1.48$\ell$의 배양기에 32개의 식물체를 이식했을 때 식물체당 일일 $CO_2$ 교환량은 19일째에 포화에 달했다. 식물체 생장에 있어서는 자연환기구보다 강제환기구의 생장이 촉진되었고, 강제환기구에서는 $CO_2$ 시용구가 무시용구보다 생장이 촉진되었다. 본 연구의 결과는 고구마 조직배양묘를 강제환기와 $CO_2$ 시용등 배양환경의 개선함으로써 순환과정을 거치지 않고 포장정식이 가능한 배양묘나 삽수의 생산이 가능함을 시사한다고 사료된다.

• Proceedings of the Materials Research Society of Korea Conference
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• 2003.03a
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• pp.192-192
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• 2003

오염된 폐수를 처리하는 과정으로 다양한 방법이 사용되고 있으나, 담체를 이용하여 미생물을 배양하고, 미생물에 의해 정수하는 방법이 이용되고 있다. 이를 위해서는 미생물을 배양을 위한 담체의 조건으로 다양한 크기의 연속기공을 갖고, 젖음성과 표면거칠기가 높으며, 이들 중 초기 미생물번식의 조건을 제공하는 기체 포집용 미세기공을 보유하고, 미생물이 성장할 수 있는 수백 $\mu\textrm{m}$까지의 다양한 크기의 연속된 기공을 갖는 미생물 담체용 다공성 세라믹스의 제조를 목적으로 본 연구를 행하였다. 본 연구는 다양한 크기의 기공분포를 형성하기 위하여 첨가물로 activated carbon과 무기염, 고분자 binder를 활성알루미나 기지재료에 사용하여 수열반응에 의해 각각의 물질이 형성할 수 있는 기공의 크기를 확인하고, 수 nm에서 수백 $\mu\textrm{m}$까지의 연속된 기공이 존재하는 담체를 제조하였다. 수열조건과 첨가물의 양에 따라 수은침투가압을 이용하여 기공의 크기와 분포를 측정하고 평균기공률을 얻을 수 있었고, 압축강도를 측정하고, 기공의 형상을 주사전자현미경을 통해 확인하였다.

• KSBB Journal
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• v.5 no.3
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• pp.223-227
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• 1990

This study describes the sorbitol production with permeabilized cells of Zymomonas mobilis immobilized in Ca-alginate. Toluene treated cells lose glucose-fructose oxidoreductase activity due to leaking of enzyme from the cells. In order to prevent this leakage, the permeabilized cells were immobilized in alginate and chitin. No significant loss of enzyme activity was apparent during 210h operation in a continuous process. The productivity of the continuous process was estimated to be about 3.5g/l -h for sorbitol at dilution rate $0.2h^{-1}$.

• KSBB Journal
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• v.17 no.1
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• pp.26-32
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• 2002

The aerobic bacterium Xanthomonas campestris was cultivated continuously in a three-phase fluidized bed bioreactor to produce extracellular polysaccharide xanthan, Fluidized particles of 8.0 mm glass beads were used for disintegrating the large air bubbles even at high viscosities to improve the gas-liquid oxygen transfer rate. Xanthin productivity [kg xanthan/kg cell dry mass·h] and molecular weight increased, with dilution rate in the continuous xanthan fermentations. The specific xanthan productivities were not limited by the oxygen transfer rate and were much higher in the continuous cultivations than those predicted by the results of the batch xanthan fermentations.

• Korean Journal of Environmental Agriculture
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• v.29 no.4
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• pp.374-380
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• 2010

This experiment was carried out to investigate the effect of light qualities and lighting types provided by LED Chamber System which designed by Rural Development Administration on growth and development of Chrysanthemum (Dendranthema grandiflorum L., cv. 'Cheonsu') plantlet cultured in vitro. The explants of single-node cuttings were exposed to monochromic or mixture radiation of blue, red, or green under continuous and intermittent lighting for 42 days. The intermittent lighting of 20 sec. on and off per minute significantly stimulated shoot elongation with lower number of internodes compared with continuous lighting treatments. However, continuous blue, red, or green light gave greater dry weight comparing the intermittent lighting, and the lowest weight was recorded at the continuous fluorescent lamp. Otherwise, the plantlet growth in dry weight or leaf area was inhibited by the green light controlled at 50 times intermittence but internode elongation was significantly increased. These results showed that the plantlets were successfully grown under the LED Chamber System controlled with different light qualities and lighting types. Quantitative growth of the plantlets was improved under the shorter photoperiod with a intermittent lighting cycle compared with continuous lighting using fluorescent lamps. It is concluded that the growth and development of in vitro plantlets such as single-node cuttings can be achieved by the controlling of light quality or lighting type during the photoperiod per day with a lower electric cost compared with conventional continuous lighting system.