• ALGAE
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• v.21 no.1
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• pp.133-139
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• 2006

Outdoor cultivation of cyanobacterium Spirulina platensis was carried out for 40 days in a batch mode. A half concentration of the SOT based on the underground water was used as culture medium. Working volume was 5.7 tons with 0.2 m depth. During cultivation, mean water temperature, DO and light intensity were all in proper conditions for the S. platensis growth. The adjustment of pH to over 10 with Na2CO3 and addition of the 1.5% natural salt were very effective to delete contaminant organisms, Chlamydomonas moewusii and Chlorella minutissima occurred one after the other in the culture. The mean productivity of the biomass based on the dry cell weight from 14 to 25 days, after the contaminants were deleted, was 7.8 g ·m–2· d–1, which was relatively high productivity in that a half concentration of the SOT was used for the culture. Underground water used in the culture minimized contaminants invasion and addition of the 1.5% natural salt was effective to delete contaminants as well as acted as mineral supplement in outdoor cultivation of S. platensis. Harvesting using the floating activity of S. platensis was effective from mass floating in day time after overnight without agitation and illumination.

• KSBB Journal
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• v.31 no.2
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• pp.120-125
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• 2016

Two-dimensional cultivation is typically used for cell growth, but the method reduces the characteristics of chondrocytes and stem cells, and limits culture area. Therefore, development of three-dimensional culture method is needed to mimic in vivo environment, improve quality of cells and scale-up efficiently. Improving proliferation and chondrogenesis is available by co-culture of chondrocytes and mesenchymal stem cells (MSCs) that leads to interaction between two kinds of cells. However, the co-culture has problems that permeability of sphere diminishes as aggregate size increased and ratio of two kinds of cells composing each spheres is different. In this work, co-cultivation method using controlled sphere composed of chondrocytes and MSCs was established and enhanced chondrogenesis. Periosteum-derived progenitor cells (PDPCs) that are appropriate for cell therapy source of articular cartilage were used as MSCs. Controlled spheres were formed in the hanging-drop plates and shifted for being induced chondrogenesis in 35-mm non-adhesive culture dishes at a rotation rate of 60 rpm. After inducing chondrogenesis, gene expressions related with chondrogenesis were found to be improved and it was apparent that the utilization of controlled spheres promoted chondrogenesis. As a result, available numbers of cells per unit area were increased and chondrogenic differentiation ability was improved compared to typical two-dimensional culture. This approach shows the potential in cartilage regeneration as it can provide sufficient numbers of chondrocytes.

• Korean Journal of Organic Agriculture
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• v.20 no.4
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• pp.503-518
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• 2012

Korean type of no-tillage cultivation method which was applied on this study used the ridge and the furrow and constantly recycling them as it was suitable for Korea's weather and farming conditions. This no-tillage cultivation was reported to have little negative impact such as reduction of production (Kwon et al., 1997). In addition, it was found to have a lot of benefits as it requires less agro-materials and energy costs as well as shortened working hours because tillage operation is not needed. (Yang et al., 2012). According to an analysis, no-tillage cultivation can reduce greenhouse gas emissions by $344.7kgCO^2$ (58%) in every 10a ($1,000m^2$) compared to ordinary pepper farming technique (Korea averages). Direct-indirect reduction effects from using fertilizer and using less amount of energy were 92% and 44% respectively both of which can be considered very high. Besides the direct effects of no-tillage cultivation, soil management using no-tillage technique raises carbon sequestration effect on soil as time goes on (West & Marland, 2002), that is why the technique is expected to have constant carbon emission reduction effect. For theses reasons, distribution and expansion of Korean type no-tillage cultivation are expected to play a role as major agro-green technologies for achieving our goal of reducing greenhouse gas emissions in agricultural sector.

• Journal of Bio-Environment Control
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• v.19 no.2
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• pp.77-81
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• 2010

The effects of $CO_2$ concentration on fruit-body formation and yield of Pleurotus ferulae (KME65003) mushroom were examined in the growing facilities for bottle cultivation. The $CO_2$ concentration levels in the growing facilities were 500 ppm, 1000 ppm, 1500 ppm and 2000 ppm of $CO_2$, controlled by different ventilation amount. Yield of fruit body was highest of 102.4 g/bottle at 1000 ppm treatment and lowest of 75.1 g/bottle at 2000 ppm. As the $CO_2$ concentration increased up to 2000 ppm, the first pinhead formation and fruit-body growing period took longer, so total growing period took 16 days at 500 ppm, but 23 days at 2000 ppm. The number of pinhead formation was highest of 12.2/bottle at 1500 ppm and valid stipes was highest of 2.8/bottle at 1000 ppm. Fruit body characteristics such as pileus and stipe diameter, and stipe length were not significant at different $CO_2$ concentration. The fruit body ratio of 20~50 g range among the whole fruit body which was classified by weight was highest of 60.3% at 1000 ppm. As a result, the suitable $CO_2$ concentration of growth and yield of Pleurotus ferulae was showed as 1000 ppm.

• Korean Journal of Soil Science and Fertilizer
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• v.26 no.1
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• pp.49-56
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• 1993

The net flux of global green house gases such as carbon dioxide($CO_2$), methane($CH_4$), and nitrous oxide($N_2O$) emitted from the rotation of paddy-upland soil during growing sesaon under different cropping system was determined. The results obtained were summarized as follows : 1. The net flux of $CO_2$ during the growing season was the highest from continuous cultivation of rice but the lowest from rotation cultivation of rice-soybean. Under the different cropping system the highst emission was from soil of continuous cultivation of rice, but the lowest from converted system. 2. The net emission of methane was the highest from the sold of continuous cultivation of rice, but the flux was remarkably decreased by differing the cropping system. 3. $N_2O$ was emitted greatly from the every two year rotation of potato-chinese cabbage and the next rank was from continuous cultivation of rice, but was decreased notably from rotation cultivation of rice-soybean and potato-chinese cabbage under rotation of paddy-upland cropping system. 4. The ratio of oxygen and carbon dioxide in the soil air was much different with glowing season, the ratio was varied with 4~10 percents for oxygen and 1~22 percents for carbon dioxide. The ratio of carbon dioxide was dozens or hundreds times to that of air, and the variation was very high also. 5. The emission of global green house gases such as carbon dioxide, methane and nitrous oxide was affected by the moisture, temperature and nutrients of soils and the growth period of crops.

• Journal of Microbiology and Biotechnology
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• v.11 no.1
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• pp.40-49
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• 2001

The present work presents a novel approach for the dynamic quantification of respiration rates on a small scale by using lysine-producing Corynebacterium glutamicum ATCC 21253. Cells sampeld from batch cultures at different times were incubated ina 12-ml scale bioreactor equipped with a membrane mass spectrometer. Under dynamic conditions, gas exchange across the gas-liquid phase, specific respiration rates, and RQ values were precisely measured. For this purpose, suitable mass balances were formulated. The transport coefficients for $O_2$ and $CO_2$, crucial for calculating the respiration activity, were determined as $k_La_{O2}=9.18h^{-1}$ and $k_La_{CO2}=5.10h^{-1}$ at 400 rpm. The application of the proposed method to batch cultures of C. glutamicum ATCC 21253 revealed the maximum specific respiration rates of $q_{O2}=8.4\;mmol\;g^{-1}h^{-1}\;and\;q_{CO2}=8.7\;mmol\;g^{-1}h^{-1}$ in the middle of the exponential growth phase after 5 h of cultivation. When the cells changed from growth to lysine production due to the depletion of the essential amino acids theonine, methionine, and leucine, $q_{O2}\;and\;q_{CO2}$ decreased significantly and RQ increased. The respiration data exhibited an excellent agreement with previous cultivations of the strain [13]. This confirms the potential of the developed approach to realistically reflect the metabolic activities of cells at their point of sampling. The short-term influence of added threonine, methionine, and leucine was highest during the shift from growth to lysine production, where $q_{O2}\;and\;q_{CO2}$ increased 50% within one minute after the pulse addition of these compounds. Non-growing, yet lysine-producing cells taken from the end of the batch cultivation revealed no metabolic stimulation with the addition of threonine, methionine, and leucine.

• Microbiology and Biotechnology Letters
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• v.16 no.5
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• pp.413-420
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• 1988

The strain capable of growing on minimal medium containing aniline as a sole source of carbon was isolated from activated sludges and identified as Pseudomonas putida biotype A. The characterizations of the strain were determined. The optimum concentration for growth of the strain was 1-20 mM of aniline. No changes of pH were detected during cultivation. Some metabolic products of biodegradation of aniline were detected after cultivation of the strain on 10 mM aniline for 48 hours. The strain showed to be resistant to streptomycin, tetracycline, trimethoprim, and sulfanilamide. The strain was also capable of utilizing other aromatic compounds related to aniline as a sole source of carbon. One plasmid carried by this strain was detected. The properties of some of the mutant strains treated with mitomycin C were also discussed. The results suggest that separate, regulatory enzyme systems capable of degrading aniline may exist in plasmid DNA.

• Journal of Korean Society of Environmental Engineers
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• v.35 no.2
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• pp.109-114
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• 2013

Polyhydroxyalkanoates (PHAs) are synthesized by numerous bacteria as carbon and energy storage compounds and are raw materials for biocompatible plastics. In this paper, the effect of $CO_2$ concentrations on the growth of C. necator and the accumulation of Poly(3-hydroxybutyrate) (P(3HB)) are investigated by increasing the $CO_2$ concentration in the substrate gas mixture. During 6 d cultivation in a nitrogen-present mineral medium, the $CO_2$ concentration did not affect the growth of the cells, while the Poly(3- hydroxybutyrate) (P(3HB)) content decreased with increasing $CO_2$ concentrations from 1% to 20%. During 4 d cultivation in the nitrogen-limited medium, the P(3HB) accumulation was the greatest at 3% $CO_2$; however, the total amount of accumulated P(3HB) was the greatest at 1% $CO_2$, which decreased with increasing $CO_2$ concentrations. The results indicate that the gas mixture with 1% $CO_2$ is the most effective in both growing the cells and accumulating P(3HB) under our experimental conditions.

• Journal of Practical Agriculture & Fisheries Research
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• v.18 no.1
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• pp.71-78
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• 2016

The present study was performed to examine the high temperature adaptability with CO₂ treatment for tomato under the condition of greenhouse cultivation during summer season. The plants with the CO₂ concentration of 1000 ppm recorded higher scores in Fm/Fo and Fv/Fm but lower score in Fo than others through the measurement of chlorophyll fluorescence, which implicated that the plants with the CO₂ concentration of 1000 ppm had more adaptability to high temperature than the others. At the condition of the same air temperature as 30℃ and 40℃, the photosynthetic rate was increased with the increase of CO₂ concentration. When in the high air temperature state of 40℃, although the photosynthic rate was low in comparison with 30℃, its value was about 18.5umolm^-2s^-1 in case of 1000ppm. The higher concentration of CO₂ made the more activated anti-oxidation enzyme (superoxide dismutase and peroxidase) for the both cultivars as 'momotaro' and 'minichal'. The cultivar of 'minichal' performed the high temperature limit as 41℃ at the CO₂ condition of 500 ppm and 43℃ at the CO₂ condition of 1000 ppm through the estimation on the variation of chlorophyll fluorescence Fo by CO₂ concentrations.

• Microbiology and Biotechnology Letters
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• v.25 no.1
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• pp.106-108
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• 1997

Blue green algaes (NIES 19, 39, 46) have been cultivated to product sigle cell protein. After 7 days of cultivation under 5000 (W/M$^{2}$) of ligth intensity, final cell concentration was 2.8 (g/L) and chlorophyll a was 4.9 (mg/L). When initial concentration of NaHCOC was 1.7% and NaNO$_{3}$ was0.25%, maximum cell concentration was obtained. Spirulina platensis NIES 39 showed faster growth rate than NIES 46. While most 39 sedimented, most 46 floated.