• Journal of Korean Society of Environmental Engineers
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• v.34 no.8
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• pp.523-527
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• 2012

This study was performed to determine optimum conditions of semi-continuous cultivation of chlorella sp. FC-21 cultivated under red light emitting diode (LED). Semi-continuous cultivation was conducted using red LED because red LED was found to be the best light source for chlorella sp. FC-21. During cultivation, phosphate and nitrogen were quickly diminished where cell concentration of chlorella was inversely proportional to the concentrations of phosphate and nitrogen in culture solution. To increase the period of dilution of culture solution, additional amounts of phosphate and nitrogen were inserted in the culture solution to increase the concentrations of phosphate and nitrogen. The cell concentrations of chlorella increased in the modified culture, but cell diameter was diminished as the dilution of culture was periodically conducted. When considered the cell concentration and cell diameter during the cultivation, amount of biomass produced was maintained constant.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.34 no.2
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• pp.156-159
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• 2001

The experiment was carried out to investigate the productivity of freshwater rotifer, Brachionus calyciflorus and marine rotifer, B. rotundiformis at various temperatures, initial inoculation and pH in a 5 L semi-continuous high density culture. Rotifers were fed by commercial condensed freshwater Chlorella. When pH was not controlled, average daily productions of freshwater and marine rotifers increased with temperature. The highest production, $44\times10^6$ rotifers, was achieved of B. calyciflorus at $32^{\circ}C$ and the possible production lasting period of B. calyciflorus was shorter than that of B. rotundiformis. Under the adjustment of pH at 7, the possible production lasting periods of B. calyciflorus and B. rotundiformis inoculated with 5,000 inds./mL were longer than those of rotifers inoculated with 10,000 inds./mL, and the daily production rate of the former was higher than that of the latter. The results from this study indicated that optimum density of the initial inoculation for the cultivation of B. calyciflorus and B. rotundiformis was 5,000 inds,/mL under the controlled conditions of pH 7 and at $32^{\circ}C$ in a semi-continuous high density culture, in terms of production rate and food cost aspects.

• Microbiology and Biotechnology Letters
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• v.20 no.3
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• pp.329-334
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• 1992

For the photoproduction of molecular hydrogen by photosynthetic bacteria in outdoor conditions, we constructed automatically controlled semi-continuous culture system. When the amount of hydrogen gas produced can be measured by a gas meter with a pulse generator, the same amount of substrate consumed for hydrogen production could be supplied by micro pump related with timers. Using the apparatus, we examined hydrogen production with immobilized cells of Rhodopseudomonas sPhaeroides B6 in outdoor conditions. In spite of severe fluctuation of weather and illumination, the culture was maintained under good control with regard to hydrogen productivity. It was possible to automate the semi-continuous outdoor culture of photosynthetic bacteria for hydrogen production.

• Journal of the Korea Organic Resources Recycling Association
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• v.9 no.1
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• pp.73-78
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• 2001

The biological carbon dioxide fixation using microalgae and photo-bioreactor has been known as an effective carbon dioxide reduction technology. As algae has many other environmental factor for its growth, the desirable cultivation factors were investigated using a green alga, Euglena gracilis Z. In this study, Euglena gracilis Z showed good $CO_2$ fixation ability in high $CO_2$ concentration of 10-20% and it contained the high protein and vitamin E enough to be used as fodder. For the mass cultivation, the continuous and semi-continuous cultivation methods were employed. The optimum hydraulic retention time (HRT) for the continuous cultivation was 4 days at carbon dioxide concentration of 10%. In this condition, the final cell number was $3.57{\times}10^6/m{\ell}$. The growth of Euglena gracilis Z increased according to the light intensity.

• Proceedings of the Korean Society of Fisheries Technology Conference
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• 2000.05a
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• pp.278-279
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• 2000

현재, 해수어와 해산 갑각류 종묘생산에 있어 해수 자치어와 유생의 초기먹이로 rotifer, Brachionus plicatilis와 B. rotundiformis를 사용한다. 또한 담수산 rotifer, calyciflorus는 담수산 자치어의 먹이로 이용이 가능하며 특히, 입이 작은 열대 관상어의 초기 먹이로 이용되고 있다. 그러나 rotifer 생산에 있어 일반적인 batch 배양 방법은 많은 공간을 차지하면서 rotifer 생산 기간 중 갑자기 전량 폐사하는 등 배양이 불안정하고 생산성을 고려할 때 양적확보를 위한 생산단가가 비교적 높다. (중략)

• Korean Chemical Engineering Research
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• v.56 no.1
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• pp.73-78
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• 2018

The main objective of this study was to evaluate the effects of acetate on the cultivation of anabena under mixotrophic condition. Four different types of acetates were used for the anebena cultivation. Among them, ethyl acetate was found to be the most effective and the growth rates linearly increased as the amount of ethyl acetate increased. When 40 mM of ethyl acetate was used, the highest values of specific growth rate of $0.979day^{-1}$ and maximum biomass productivity of $0.293g\;L^{-1}\;d^{-1}$ were obtained. On the contrary, input of acetic acid and butyl acetate inhibited the growth of anabena. For aeration tests, 0.54 vvm was optimum for anabena cultivation. For a semi-continuous cultivation test, ethyl acetate was used after 0.54 vvm test was finished. Then, test continued under 0.54 vvm and 40 mM of ethyl acetate. Lower specific growth rate and maximum biomass productivity were obtained compared to those from batch cultivation tests. However, the greatest maximum concentration of 5.91 g/L was obtained during the semi-continuous cultivation test.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.32 no.6
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• pp.748-752
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• 1999

This study was carried out to compare the growth and fatty acids composition of the rotifer (Brachionus rotundiformis) cultured in high density by the various enrichments and culture methods. The rotifer fed on condensed freshwater Chlorella was enriched with $\omega$-yeast, Algamac, Super Selco and marine Chlorella. In another culture method, the rotifer was cultured with enrichment supplements for 6 hours after feeding with condensed freshwater Chlorella supplement for 18 hour. The rotifer fed with condensed marine Chlorella for 24 hours without fieshwater Chlorella was used as a control group. Culture tanks (5 $\ell$ working volume) was immersed in a water bath ($28^{\circ}C$). The density of rotifer and dissolved oxygen level in water was stable in control group of rotifer cultured with condensed marine Chlorella for 24 hours and the n-3 HUFA content of rotifer was the highest among the rotifer culture methods. However, the density of rotifer and dissolved oxygen level in the groups of rotifers enriched with $\omega$-yeast, Algamac and Super Selco by methods were drastically decreased, The n-3 HUFA contents of rotifers enriched by Super Selco were higher than those of rotifer enriched by either $\omega$-yeast or Algamac in both methods. The results from this experiment indicated that supplementation of condensed marine Chlorella for 24 hour by the semi-continuous culture was effective for the improvement of the nutritional value of rotifer and it could provide the stable growth condition for rotifer culture in high density.

• Journal of Korean Society of Environmental Engineers
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• v.39 no.6
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• pp.332-338
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• 2017

The purpose of this study was to determine optimum value of aeration, acetate dosage, and $CO_2$ input for the cultivation of Scenedesmus acuminatus. Highest specific growth rate and maximum biomass productivity was obtained by the aeration of 0.72 vvm and lower specific growth rates and maximum biomass productivity were obtained for other aeration tests. When putting 0.3 M of ammonium acetate in JM medium, the highest specific growth rate and maximum biomass productivity were obtained. $CO_2$ input tests were performed during semi-continuous culturing tests. The highest specific growth rate ($0.460d^{-1}$) and maximum biomass productivity ($0.936gL^{-1}d^{-1}$) were obtained after replacing 50% of solution with 0.3 M of acetate solution for $CO_2$ input tests. However, more dilutions after the first dilution resulted in lower specific growth rate and maximum biomass productivity. In aeration tests, the highest specific growth rate ($0.381d^{-1}$) and maximum biomass productivity ($0.253gL^{-1}d^{-1}$) were obtained when cultivating it with JM medium, but the specific growth rate and maximum biomass producitivty were significantly decreased when 50% of solution was replaced by acetate containing solution.

• KSBB Journal
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• v.4 no.2
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• pp.185-190
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• 1989

Semicontinuous alcohol fermentation of Jerusalem Artichoke by K. fragilis CBS 1555 was performed to investigate the effect of the effective dilution rate and influent sugar concentration to the ethanol concentration and alcohol productivity at steady state. When the time interval for the replacement of fresh influent with fermentation broth was less than or equal to 1 hr, the effective dilution rate was found out to be equal to the specific growth rate. Wash out was not occurred until the effective dilution rate, 0.425 hr-1, and the maximum alcohol productivity was around 5.5 g/1·hr. In this case, the effective dilution rate was 0.25 hr-1 and the influent sugar concentration was distributed from 85 g/l to 135 g/1.

• Korean Journal of Plant Tissue Culture
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• v.22 no.1
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• pp.15-28
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• 1995

In order to identify an antifreeze proteins responsible for freeze-tolerance in barley the proteins accumulated in extracellular space during cold acclimination were extracted and analyzed. After 42 days cold treatment there were several proteins sized of 70, 21, 16, 14 KDa increased in their amount accumulated in extracellular space. In addition, continuously sized polypeptides smaller than 10 KDa were found to be increased in their amount as cold treatment prolongs. Since these proteins were not detectable in total leaf protein extract it appears that the procedure used to isolate extracellular extract was valid. A similarity in profile of the extracellular proteins isolated from barley and rye may indicate a possibility for these proteins to be an antifreeze proteins since the same extract from rye was reported to show an antifreezing activity.