• Journal of Microbiology and Biotechnology
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• v.23 no.12
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• pp.1747-1756
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• 2013

The aim of this paper was to study the effect of spent medium recycle on Spodoptera exigua Se301 cell line proliferation, metabolism, and baculovirus production when grown in batch suspension cultures in Ex-Cell 420 serum-free medium. The results showed that the recycle of 20% of spent medium from a culture in mid-exponential growth phase improved growth relative to a control culture grown in fresh medium. Although both glucose and glutamine were still present at the end of the growth phase, glutamate was always completely exhausted. The pattern of the specific glucose and lactate consumption and production rates, as well as the specific glutamine and glutamate consumption rates, suggests a metabolic shift at spent medium recycle values of over 60%, with a decrease in the efficiency of glucose utilization and an increase in glutamate consumption to fuel energy metabolism. Baculovirus infection provoked a change in the metabolic pattern of Se301 cells, although a beneficial effect of spent medium recycle was also observed. Both growth rate and maximum viable cell density decreased relative to uninfected cultures. The efficiency of glucose utilization was dramatically reduced in those cultures containing the lowest percentages of spent medium, whereas glutamine and glutamate consumption was modulated, thereby suggesting that infected cells were devoted to virus replication, retaining their ability to incorporate the nutrients required to support viral replication. Recycle of 20% of spent medium increased baculovirus production by around 90%, thus showing the link between cell growth and baculovirus production.

• Microbiology and Biotechnology Letters
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• v.24 no.4
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• pp.519-524
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• 1996

The kinetics of growing microalga, Spirulina platensis was investigated to treat swine wastes with optimum growth conditions. Temperature was varied from 15 to 40$\circ$C at three different light intensities, 6 W/m$^{2}$, 12 W/m$^{2}$ and 24 W/m$^{2}$. The specific growth rate was increased as temperature increased up to 30$\circ$C. The activation energy was estimated as 13.5 kcal/mol by an Arrhenius relationship. 0.24 (1/day) of specific growth rate was obtained from batch cultivation with 30% swine wastes, compared to 0.31 (1/day) from clean culture. It was found that Spirulina platensis was able to reduce 70-93% of PO$_{4}$$^{3-}$ -P, 67-93% of inorganic nitrogen, 80-90% of COD and 37-56% organic nitrogen by adding various concentrations of swine wastes for 12 days of batch cultivation. Rate constants for removing nitrates and phosphates in treating swine wastes were estimated as 0.17 (1/day) and 0.14 (1/day) in the first order reaction, respectively. 1.52 (g/L) of maximum cell density was maintained at 0.20 (1/day) of dilution rate in continuous culture, adding 20% swine wastes for 30 days. The chemical composition of the biomass obtained from the process showed 58.7% of protein, 11.0% of lipid and 15.6% of ash.

• Microbiology and Biotechnology Letters
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• v.21 no.4
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• pp.348-353
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• 1993

The optimal conditions for operating a moving-aeration bioreactor were determined as 30rpm and 150 (ml/min) of air flow rate, which can yield ca. 7.3 (l/h)of maximum mass transfer coefficient. It was also found that the agitation speed played much much important role than air input rate in oxgen transfer into the medium. $2.6{\times}10^6$ (cells/ml) and 0.6 (ml/l) of maximum cell denisty and IL-2 production were observed in batch cultivation of IL-2 producing BHK cell line. 0.53 (mM/l/h) of oxygen uptake rate was also estimated. The performance of a moving-aeration bioreactor (specific growth rate and oxygen uptake rate, etc.) was superior to other culture systems, such as cell-life and static membrane aeration bioreactors. Ii must be useful to apply this reactor to many culture processes by improving structural limitations in scaling-up the system.

• Journal of Korean Society of Water and Wastewater
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• v.27 no.4
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• pp.457-468
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• 2013

Based on the activated sludge model(ASM), a mathematical model which represents the aerobic sludge digestion by sequencing batch reactor(SBR) combined with ultrasonic treatment was composed and performed in this study. Aerobic digestion using sequencing batch reactor(SBR) equipped with ultrasound treatment was also experimented for the purpose of parameter calibration. Most of the presented kinetic parameters in ASM or ASM2 could be used for the aerobic digestion of sludge but the parameters related in hydrolysis and decay rate needed modification. Hydrolysis rate constant of organic matter in aerobic condition was estimated at $0.3day^{-1}$ and the maximum growth rate for autotrophs in aerobic condition was $0.618day^{-1}$. Solubilization reactions of particulate organics and nitrogen by ultrasonication was added in this kinetic model. The solubilization rate is considered to be proportional to the specific energy which is defined by specific ultrasound power and sonication time. The solubilization rate constant by ultrasonication was estimated at $0.202(W/L)^{-1}day^{-1}$ in this study. Autotrophs as well as heterotrophs also decomposed by ultrasonic treatment and the nitrification reaction was limited by the lack of autotrophs accumulation in the digester.

• Proceedings of the Korean Society for Agricultural Machinery Conference
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• 2000.11c
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• pp.764-769
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• 2000

A new transplant production system that produces high quality plug seedlings of specific crop has been studied. It is a plant factory designed to produce massive amount of virus free seedlings. The design concept for building this plant factory is to realize maximum energy efficiency and minimum initial investment and running cost. The basic production strategy is the sitespecific management. In this case, the management of the growth of individual plantlet is considered. This requires highly automated and information intensive production system in a closed aseptic environment the sterilized specific crops. One of the key components of this sophisticated system is the irrigation system. The conditions that this irrigation system has to satisfy are: 1. to perform the site specific crop management in irrigation and 2. to meet the no waste standard. The objective of this study is to develop an irrigation scheduling that can implement the no waste standard.

• Journal of the Korean Society of Fisheries and Ocean Technology
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• v.50 no.4
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• pp.447-454
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• 2014

The marine microalgae Chaetoceros calcitrans was cultured under a fluorescent lamp (CON) and light-emitting diodes (LEDs) of various wavelengths (blue, LB; red, LR; green, LG; white, LW); changes in growth, fucoxanthin, chlorophyll-a, amino acid and fatty acid profiles were investigated. LR-exposed cultures exhibited the highest specific growth rate (SGR) (0.34), whereas LG-exposed cultures showed the lowest SGR (0.26). After cultivation for 10 days, the maximum dry cell weight (g/L) of LR-exposed cultures was significantly higher than that of those exposed to other light conditions (LR${\geq_-}$CON>LB${\geq_-}$LW${\geq_-}$LG). Eicosapentaenoic acid (EPA) levels were significantly higher in CON-exposed cultures compared to those exposed to LW (P<0.05), with no marked difference compared to those exposed to LB, LR and LG (P>0.05). The fucoxanthin content was highest in LB-exposed cultures ($6.3{\mu}g/mL$), whereas LW showed the lowest ($3.6{\mu}g/mL$; P<0.05). Chlorophyll-a content was highest in cultures exposed to LB compared to other light sources. These results suggest consistent differences in growth and biochemical composition after exposure to light of different wavelengths.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.46 no.3
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• pp.259-265
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• 2013

The marine microalgae Nannochloropsis sp. was cultured under a metal halide lamp (MH) or light-emitting diodes (LEDs) of various wavelengths (blue, LB; red, LR; yellow, LY; green, LG; white, LW); changes in growth, total carotenoid, chlorophyll a, amino acid and fatty acid profiles were investigated. LB-exposed cultures exhibited the highest specific growth rate (SGR) (0.32), whereas LY-exposed cultures showed the lowest SGR (0.18). After cultivation for 9 days, the maximum dry cell weight (g/L) of LB-exposed cultures was significantly higher than that of those exposed to other light conditions (LB>MH>LW$${\geq_-}LG{\geq_-}$$LR>LY). The essential amino acid (EAA, %) contents of cultures exposed to LG, LB, LR and MH were higher than those exposed to LY and LW (P<0.05). Eicosapentaenoic acid and n-3 highly unsaturated fatty acid levels were significantly higher in MH-exposed cultures compared to those exposed to LY (P<0.05), with no marked difference compared to those exposed to LB, LG, LR and LW (P>0.05). The total carotenoid content was highest in LR-exposed cultures (18.0 mg/L), whereas MH showed the lowest (11.8 mg/L; P<0.05). Chlorophyll a content was highest in cultures exposed to LR compared to other light sources. These results suggest consistent differences in growth and biochemical composition after exposure to light of different wavelengths.

• KSBB Journal
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• v.8 no.5
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• pp.473-477
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• 1993

Up to now, 10% Fetal Bovine Serum(FBS(V/V)) was added to basal medium for the cultivation of hybridoma. For the cultivation of hybridoma cell line, CH07E02, against colon cancer, serum concentration was reduced to 3% FBS without influence on cell growth and maximum cell concentration. By the addition of cell growth promoting substances-insulin (I), pyruvate (P), oxaloacetate(O), Pluronic F-68(P) and 2-mercaptoethanol(2-ME)-to 1% FBS medium, a cell density higher than that with 1% FBS medium alone was achieved. FBS 3% medium was replaced by very cheap 2% Calf Serum (CS) medium without influence on cell growth rate and concentration. Cells grew vigorously in 0.5% CS＋IPOP medium. This composition was used during suspension culture and exhibited good viability and high specific growth rate.

• Journal of Life Science
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• v.7 no.4
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• pp.377-383
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• 1997

The acute toxicity effect of triorganotin of trioganotin on the growth of microalgae and shellfish was investigated through flask culture. The value of 120 hr-LC$_{50}$ that is the median lethal concentration of TBTO on the shellfish (R. philipinarum) was found to be 6 $\mu$g/L. The acute toxicity effect of TBTO on T. suecica was obviously shown even at the concentration of 0.5 $\mu$g/L, and the effect diminished as the initial cell density increased. The effect also diminished less in the experiment done under aeration than in that done under non-aeration. To design a chemostat system for the test of chronic toxicity, the culture of T. suecica was executed in photobioreactor. In batch culture, the profiles of chlorophyII a and D.C.W. showed the growth of T. suecica very well, and the maximum specific growth rate was estimated to be 0.54 d$^{-1}$. with this value, as a dilution rate in contimuous culture, pH was nicely maintained between 7 and 9 when air was supplied with 3% CO$_{2}$. From all results and the natural environment of clam, a novel chemostat system was invented. Through this system, we can observe each independent toxicity effect of TBTO and plankton and combined toxicity effect as well.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.46 no.2
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• pp.89-94
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• 2001

Sword bean belongs to the subgenus Canavalia in the genus Canavalia. White and reddish varieties in sword bean were tested to obtain the basic information for improving the yield, quality, and cultural environments through the quantitative growth analysis. Growing plants were sampled at intervals of 10 days from 20 days after sowing. Whole plant weight increased during the period of 11-20 days after sowing in both varieties. The weight of each organ between two varieties increased similarly except leaf area. Whole plant weight changed more close to pod weight than any other characters. The leaf areas of both varieties increased from 50 days after sowing, var. white displayed S type curved line but var. reddish displayed slow S type curved line. The SGR of whole plant weight in both varieties had 3 maxima and 2 minima, 3 maxima and first minimum were shown at the same period but the second minimum was shown at different period. Both varieties showed bimodal curved line. All SGR of each organ and leaf area were shown the 2 maxima and 1 minimum in both varieties. The changes of SLA and LAR were not remarkable between two varieties but these were united together with the maximum of whole plant weight and root weight. ULWR and ULWR were shown similar in both varieties. Reddish variety was more prosperous in early growth stage than white variety because SLA, LAR and LWR were high. In surplus weight, both varieties increased rapidly during the period of 111-120 days after sowing that was applicable to the maximum SGR of pod weight. Surplus weight of var. white increased markedly during the same period comparing those of var. reddish.