• Journal of Microbiology and Biotechnology
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• v.28 no.4
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• pp.630-637
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• 2018

The high rate algal ponds (HRAP) powered and mixed by a paddlewheel have been widely used for over 50 years to culture microalgae for the production of various products. Since light incidence is limited to the surface, water depth can affect microalgal growth in HRAP. To investigate the effect of water depth on microalgal growth, a mixed microalgal culture constituting three major strains of microalgae including Chlorella sp., Scenedesmus sp., and Stigeoclonium sp. (CSS), was grown at different water depths (20, 30, and 40 cm) in the HRAP, respectively. The HRAP with 20cm of water depth had about 38% higher biomass productivity per unit area ($6.16{\pm}0.33g{\cdot}m^{-2}{\cdot}d^{-1}$) and required lower nutrients and energy consumption than the other water depths. Specifically, the algal biomass of HRAP under 20cm of water depth had higher settleability through larger floc size (83.6% settleability within 5 min). These results indicate that water depth can affect the harvesting process as well as cultivation of microalgae. Therefore, we conclude that water depth is an important parameter in HRAP design for mass cultivation of microalgae.

• Microbiology and Biotechnology Letters
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• v.26 no.6
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• pp.537-544
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• 1998

The cultivation conditions of transformant Alcaligenes eutrophus AER5 harboring cloned phbC gene for mass production of poly (3-hydroxybutyrate-3-hydroxyvalerate)[P(3HB-3HV)] containing high molar fraction of 3-hydroxyvalerate (3-HV) were investigated. In two-stage batch cultivation, transformant accumulated P(3HB-3HV) containing 52.2 mol% of 3HV compared to 30 mol% of parent strain A. eutrophus H16. The increased 3-HV molar fraction was due to the amplified activity of PHB synthase participating in condensation of 3-HB and 3-HV. To increase efficiency of P(3HB-3HV) accumulation, fructose was added along with precursor compound valerate, and total cell mass and P(3HB-3HV) concentrations remarkably increased, but not 3-HV molar fraction. The effect of magnesium ion showed that P(3HB-3HV) concentration and 3-HV molar fraction were significantly increased upto 6.1 g/L and 71.3 mol% at 0.01 g/L of MgSO$_4$, respectively. The efficiency of several pH adjuster, NaOH, NaOH and (NH$_4$)$_2$SO$_4$, and NH$_4$OH, on total cell mass, p(3HB-3HV) concentration, and 3-HV molar fraction was also compared. To overcome the disadvantage of two-stage cultivation, one-stage intermittent fed-batch cultivation was attempted, such a way 10.0 g/L of fructose was supplied for cell growth at initial 36 hr and then 10.0 g/L of valerate and 5.0 g/L of fructose were applied to induce the accumulation of P(3HB-3HV), consequently, 10.4 g/L of P(3HB-3HV) with 38 mol% of 3-HV fraction could be obtained after 72 hr. These results can be used for elucidating cultivation strategy for mass production of P(3HB-3HV) containing high 3-HV molar fraction using transformant A. eutrophus AER5 harboring cloned phbC gene.

• Biotechnology and Bioprocess Engineering:BBE
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• v.7 no.6
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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.

• Journal of Microbiology and Biotechnology
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• v.13 no.5
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• pp.641-646
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• 2003

An accurate and efficient method for measuring the mass of hairy roots using conductometry is established. A conductivity equation expressed in terms of the concentration of the ion species in the medium is suggested. By using this equation, the effect of the individual ions on the total conductivity can be quantitatively analyzed. An equation for the in situ estimation of the cell growth coefficient for determining the mass of hairy roots is established based on measurements of the nitrogen concentration and conductivity during cultivation. The proposed equation does not require preliminary experiments to determine the cell growth coefficient. Instead, the physiological characteristics of the plant species are reflected by introducing the cellular nitrogen content. Since the cell growth coefficient is determined by measuring the major ionic nutrient concentrations, it is more effective to express the dynamics of an actual culture system. This improved method for determining the mass of hairy roots was successfully utilized in a fed-batch culture system.

• 한국생물공학회:학술대회논문집
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• 2005.10a
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• pp.312-315
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• 2005

A process for efficient recycle fed-batch culture was carried out to increase cell mass and spore production by Lactic acid bacteria isolated from Kimchi. A large quantity of cell mass obtained by feeding concentration of sugar in recycle fed-batch culture. When the high density of salt was created that the cell mass was come-down. In this study, cultured in different feeding concentration of sugar conditions. Lactic acid bacteria by recycle fed-batch culture was investigated in 2L working volume of fermenter, obtained the maximum cell mass was 15.17g/L.

• 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.

• Journal of Mushroom
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• v.1 no.1
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• pp.1-8
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• 2003

Mushroom cultivation in Korea was launched in the early 1960's. At that time Korean government started a program for increasing cultivation of button mushroom (Agaricus bisporus) and oak mushroom (Lentinula edodes) to export agricultural products and to increase farm income. National research institutes under Rural Development Administration, Korea Forest Service, etc. play a leading role in mushroom industry as follows : Development and spread of genetically superior commercial strains, good spawns, and cultivation techniques. Training and field advice to lead farmers for mass production of high quality mushrooms. Political support of facilities and establishments for mushroom cultivation. Several mushrooms including oak mushroom, button mushroom, oyster mushroom, winter mushroom, Ganoderma, P. eryngii, etc. have been popularized for their cultivation techniques and produced in large quantities in the farm. According to a recent statistics, mushrooms have been grown by about 20,000 farm households, in Korea and the gross production of fresh mushrooms is estimated about 170,000 M/T. The gross production of oyster mushroom is the highest followed by winter mushroom, oak mushroom and button mushroom. The gross amount of mushroom production stands over 700 billion won. Thus, mushroom industry goes to the most important cash crop to be produced yearly.

• Journal of Korean Society of Water and Wastewater
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• v.32 no.5
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• pp.371-379
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• 2018

The lack of seed sludges for Ammonium Oxidizing Bacteria (AOB) and slow-growing ANaerobic AMMonium OXidation (ANAMMOX) bacteria is one of the major problem for large-scale application. In this study, $24m^3$ of single-stage SBR (Sequencing Batch Reactor) was operated to remove nitrogen from reject water using AOB and ANAMMOX bacteria cultivated from activated sludge in the field. The ANAMMOX activity was found after 44 days of cultivation in the ANAMMOX cultivation reactor, and then $0.66kg\;N/m^3/d$ of the nitrogen removal rate was achieved at $0.78kg\;N/m^3/d$ of the nitrogen loading rate at 153 days of cultivation. The AOB cultivation reactor showed $0.2kg\;N/m^3/d$ of nitrite production rate at $0.4kg\;N/m^3/d$ of nitrogen loading rate after 36 days of operation. The cultivated ANAMMOX bacteria and AOB was mixed into the single-stage SBR. The feed distribution was applied to remove total nitrogen stably in the single-stage SBR. The nitrogen removal rate in the single-stage SBR was gradually enhanced with an increase of specific activities of both AOB and ANAMMOX bacteria by showing $0.49kg\;N/m^3/d$ of the nitrogen removal rate at $0.56kg\;N/m^3/d$ of the nitrogen loading rate at 54 days of operation.

• Korean Journal of Soil Science and Fertilizer
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• v.45 no.2
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• pp.280-286
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• 2012

Clean energy farming is the agricultural activity to improve an efficiency of agricultural energy use and to replace fossil fuels. This study was carried out to establish the clean energy farming system in the controlled cultivation of vegetable crop (cucumber) adopting the biogas production facility. In order to design the clean energy farming system, mass and energy balance was analyzed between the controlled cultivation system and the biogas production facility. Net yearly heating energy demands ($E_{YHED}$) of forcing and semi-forcing cultivation types were 48,697 and $13.536Mcal\;10^{-1}$ in the controlled cultivation of vegetable cucumber. To cover these $E_{YHED}$, the pig slurry of 511 and $142m^3\;10a^{-1}$ (biogas volume of 9,482 and $2,636Nm^3\;10a^{-1}$, respectively, as 60% methane content) were needed in forcing and semi-forcing cultivation types. The pig slurry of $511m^3\;10a^{-1}$ caused N 1,788, $P_2O_5$ $511kg\;10a^{-1}$ in the forcing cultivation type, and the pig slurry of $142m^3\;10a^{-1}$ caused N 497, $P_2O_5$ $142kg\;10a^{-1}$ in the semi-forcing cultivation type. The daily heating energy demand ($E_{i,DHED}$) by the time scale analysis showed the minimum $E_{i,DHED}$ of $7.7Mcal\;10a^{-1}\;day^{-1}$, the maximum $E_{i,DHED}$ of $515.1Mcal\;10a^{-1}\;day^{-1}$, and the mean $E_{i,DHED}$ of 310.2 in the forcing cultivation type. And the minimum $E_{i,DHED}$, the maximum $E_{i,DHED}$, and the mean $E_{i,DHED}$ were 5.3, 258.0, and $165.1Mcal\;10a^{-1}\;day^{-1}$ in the semi-forcing cultivation type, respectively. Input scale of biogas production facility designed from the mean $E_{i,DHED}$ were 3.3 and $1.7m^3\;day^{-1}$ in the forcing and the semi-forcing cultivation type. The maximum $E_{i,DHED}$ gave the input scale of 5.4 and $2.7m^3\;day^{-1}$ in the forcing and the semi-forcing cultivation type.

• 한국균학회소식:학술대회논문집
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• 2018.05a
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• pp.27-27
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• 2018

The production scale of mushroom cultivation in Korea is approximately 600 billion won, which is 1.6% of the Korean gross agricultural output. Annually, ca. 190,000 tons of mushrooms are harvested in Korea. Although the numbers of mushroom farms and cultivators are constantly decreasing, the total mushroom yields are increasing due to the large-scale cultivation facilities and automation. The recent expansion of the well-being trend causes increase in mushroom consumption in Korea: annual per capita consumption of mushroom was 3.9kg ('13) that is a little higher than European's average. Thus the exports of mushrooms, mainly Flammulina velutipes and Pleurotus ostreatus, have been increased since the middle of 2000s. Recently, however, it is slightly reduced. However, Vietnam, Hong Kong, the United States, the Netherlands and continued to export, and the country has increased recently been exported to Australia, Canada, Southeast Asia and so on. Canned foods of Agaricus bisporus was the first exports of the Korean mushroom industry. This business has reached the peak of the sale in 1977-1978. As Korea initiated trade with China in 1980, the international prices of mushrooms were sharply fall that led to shrink the domestic markets. According to the high demand to develop new items to substitute for A. bisporus, oyster mushroom (Pleurotus ostreatus) was received the attention since it seems to suit the taste of Korean consumers. Although log cultivation technique was developed in the early 1970s for oyster mushroom, this method requires a great deal of labor. Thus we developed shelf cultivation technique which is easier to manage and allows the mass production. In this technique, the growing shelf is manly made from fermented rice straw, that is the unique P. ostreatus medium in the world, was used only in South Korea. After then, the use of cotton wastes as an additional material of medium, the productivity. Currently it is developing a standard cultivation techniques and environmental control system that can stably produce mushrooms throughout the year. The increase of oyster mushroom production may activate the domestic market and contribute to the industrial development. In addition, oyster mushroom production technology has a role in forming the basis of the development of bottle cultivation. Developed mushroom cultivation technology using bottles made possible the mass production. In particular, bottle cultivation method using a liquid spawn can be an opportunity to export the F.velutipes and P.eryngii. In addition, the white varieties of F.velutipes were second developed in the world after Japan. We also developed the new A.bisporus cultivar "Sae-ah" that is easy to grown in Korea. To lead the mushroom industry, we will continue to develop the cultivars with an international competitive power and to improve the cultivation techniques. Mushroom research in Korea nowadays focuses on analysis of mushroom genetics in combination with development of new mushroom varieties, mushroom physiology and cultivation. Further studied are environmental factors for cultivation, disease control, development and utilization of mushroom substrate resources, post-harvest management and improvement of marketable traits. Finally, the RDA manages the collection, classification, identification and preservation of mushroom resources. To keep up with the increasing application of biotechnology in agricultural research the genome project of various mushrooms and the draft of the genetic map has just been completed. A broad range of future studies based on this project is anticipated. The mushroom industry in Korea continually grows and its productivity rapidly increases through the development of new mushrooms cultivars and automated plastic bottle cultivation. Consumption of medicinal mushrooms like Ganoderma lucidum and Phellinus linteus is also increasing strongly. Recently, business of edible and medicinal mushrooms was suffering under over-production and problems in distribution. Fortunately, expansion of the mushroom export helped ease the negative effects for the mushroom industry.