• Journal of Applied Biological Chemistry
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• v.58 no.3
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• pp.209-218
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• 2015

Fructooligosaccharides have been mainly produced by microbial fructosyltransferases (FTase) enzymes. The present work focuses on the optimization of medium composition and cultivation parameters affecting FTase produced by Penicillium aurantiogriseum AUMC 5605 in shake flask cultivation. FTase production was optimized in two steps using DeMeo's fractional factorial design. A 1.46-fold increase in FTase production (105.4 U/mL) was achieved using the optimized culture medium consisting of (g/L): sucrose, 600; yeast extract, 10; $K_2HPO_4$, 5; $MgSO_4{\cdot}7H_2O$, 0.5; $(NH_4)_2SO_4$, 1.0 and KCl, 0.5. The obtained results showed that the maximum FTase enzyme activity was produced at initial cultivation pH values ranging from 6.0-6.5, at agitation speed of 200 rpm and using vegetative fungal cells as inoculum. Moreover, results showed that optimization of medium composition and some cultivation parameters resulted in an increase of about 93.7% in the enzyme activity than the nonoptimized cultivation conditions after 96 h of cultivation. Additionally, maximum production and specific production rates recorded 2340 U/L/h and 102 U/L/h/g cells, respectively.

• Microbiology and Biotechnology Letters
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• v.48 no.3
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• pp.337-343
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• 2020

In this study, the medium optimization for cell growth and metabolite formation of Haematococcus sp. under mixotrophic cultivation was investigated. As a result, modified MS medium was selected as the basal medium; glucose was selected as the carbon source, with an optimum concentration of 10 g/l, and potassium nitrate was chosen as the nitrogen source, with an optimum concentration of 1.9 g/l. Under optimum conditions, Haematococcus sp. demonstrated an increase in biomass concentration from 0.18 gDW/l to 5.58 gDW/l in 14 days, after which there was a 31-fold increase in its growth. At the same time, the concentrations of chlorophyll and carotenoids were 172.16 mg/l and 42.33 mg/l, respectively. This work will contribute to the basic data for mass cultivation of microalgae.

• Nuclear Engineering and Technology
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• v.54 no.5
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• pp.1835-1844
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• 2022

Single-orifice plate is wildly utilized in the piping system of the nuclear power plant to throttle and depressurize the fluid of the pipeline. The cavitation induced by the single-orifice plate may cause some serious vibration of the pipeline. This study aims to find the optimal designs of the single-orifice plates that may have weak cavitation possibilities. For this purpose, a new single-orifice plate with a convergent-flat-divergent hole was modeled, a multi-objective optimization method was proposed to optimize the shape of a single-orifice plate, while computational fluid dynamics method was adopted to obtain the fluid physical quantities. The reciprocal cavitation number and the developmental integral were treated as cavitation indexes (e.g., objectives for the optimization algorithm). Two non-dominant designs ultimately achieved illustrated obvious reduction in the cavitation indexes at a Reynolds number Re = 1 ×10⁵ defined based on fluid velocity. Besides, the sensitivity analysis and temperature effects were also performed. The results indicated that the convergent angle of the single-orifice plate dominants the cavitation behavior globally. The optimal designs of single-orifice plates result in lower downstream jet areas and lower upstream pressure. For a constant Reynolds number, the higher temperature of liquid water, the easier it is to undergo cavitation. Whereas there is a diametric phenomenon for a constant fluid velocity. Moreover, the regression models were carried out to establish the mathematical relation between temperature and cavitation indexes.

• Journal of Microbiology and Biotechnology
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• v.30 no.8
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• pp.1252-1260
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• 2020

(R)-2-(4-hydroxyphenoxy)propionic acid (HPOPA) is a key intermediate for the preparation of aryloxyphenoxypropionic acid herbicides (R-isomer). In order to improve the HPOPA production from the substrate (R)-2-phenoxypropionic acid (POPA) with Beauveria bassiana CCN-A7, static cultivation and H₂O₂ addition were attempted and found to be conducive to the task at hand. This is the first report on HPOPA production under static cultivation and reactive oxygen species (ROS) induction. On this premise, the cultivation conditions and fermentation medium compositions were optimized. As a result, the optimal carbon source, organic nitrogen source, and inorganic nitrogen source were determined to be glucose, peptone, and ammonium sulfate, respectively. The optimal inoculum size and fermentation temperature were 13.3% and 28℃, respectively. The significant factors including glucose, peptone, and H₂O₂, identified based on Plackett-Burman design, were further optimized through Central Composite Design (CCD). The optimal concentrations were as follows: glucose 38.81 g/l, peptone 7.28 g/l, and H₂O₂ 1.08 g/l/100 ml. Under the optimized conditions, HPOPA titer was improved from 9.60 g/l to 19.53 g/l, representing an increase of 2.03-fold. The results obtained in this work will provide novel strategies for improving the biosynthesis of hydroxy aromatics.

• Journal of the Korean Society of Food Science and Nutrition
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• v.26 no.6
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• pp.1039-1043
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• 1997

Correlation among color intensity, electron donating ability to $\alpha$, $\alpha$-diphenyl-$\beta$-dicrylhydrazy(DPPH) and cultivation conditions by Bacillus subtilis DC-2 were tested with response surface methodology. Both of pigment generation ability and DPPH were more affected by temperature than any other factor. The highest correlation was appeared between color intensity and DPPH as 0.8364 which is significant at 1% level. After fixing cultivation time which is not significant at 10% level to 84hrs as optical cultivation time, response surface methodology was conducted in regarding temperature and color intensity. As a result of overlapped contour map of color intensity and DPPH, when cultivation temperature was in the range of 38.9~41.1$^{\circ}C$ and pH was in the range of 8.34~9.12, optical density of color intensity was predicted higher than 0.374 at 390nm and DPPH was infered higher than 1.310 at 528nm. In the range of optical culture condition, cultivation temperature, pH and cultivation time was fixed to 4$0^{\circ}C$, 8.5 and 85hrs, respectively. In resulting, observation value of color intensity and DPPH was in the range of anticipation value as 0.386 at 390nm and 1.332 at 528nm respectively.

• Proceedings of the Korean Society of Agricultural Engineers Conference
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• 2003.10a
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• pp.351-354
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• 2003

This study was carried out to set up design criteria of Eryngii cultivation houses. Optimization of lay-out efficiency together with analysis of structural safety were two main tools of approaching toward reasonable models to be developed. Some models tentatively assumed according to the result of field survey and analysis were compared in the aspect of structural safety as well as energy efficiency.

• Korean Chemical Engineering Research
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• v.55 no.1
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• pp.74-79
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• 2017

In this study, the optimization of several factors for Chlorella saccharophila cultivation was investigated. The studied factors were medium type, culture type, inoculum size, sugar/nitrogen source type and concentrations. As a result, the optimized conditions for C. saccharophila cultivation were found to be the best at 3% (v/v) inoculum, 30 g/L glucose and 0.95 g/L $NaNO_3$ under mixotrophic culture. Under the optimized condition, the content of oil was high at 12 day, whereas, the amount of biomass and chlorophyll were high at 10 day.

• Journal of the Korea Society of Computer and Information
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• v.29 no.4
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• pp.55-62
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• 2024

In this paper, we propose a thin-film hydroponic plant cultivator using HMI display and IoT technology. Existing plant cultivators were difficult to manage due to soil-based cultivation, and it was difficult to optimize environmental conditions due to the open cultivation environment. In addition, there are problems with plant cultivation as immediate control is difficult and growth of plants is delayed. To solve this problem, a cultivation environment was established by connecting the MCU and sensors, and the environment information could be checked and quickly controlled by linking with the HMI display. Additionally, a case was applied to minimize changes in environmental information. Implementation of a thin-film hydroponic cultivation system made soil management easier, improved functionality through operation and control, and made it easy to understand environmental information through the display. The effectiveness of rapid growth was confirmed through crop cultivation experiments in existing growers and hydroponic growers. Future research directions will include optimizing growth information by transmitting and storing cultivation environment information and linking and comparing growth information using vision cameras. It is expected that this will enable efficient and stable plant cultivation.

• Natural Product Sciences
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• v.27 no.3
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• pp.187-192
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• 2021

Cordycepin is a characteristic bioactive compound of Cordyceps militaris with various beneficial effects. Cordyceps grows on both grains and insects, and the content of cordycepin varies depending on the cultivation conditions. In this study, the effect of culture conditions on the cordycepin content was analyzed and the extraction conditions were optimized. Analysis of cordycepin content in Pupae-Cordyceps found that it was highly affected by temperature in culture conditions. In the case of mycelium, it grows well at 20 and 25 ℃, but not at 30 ℃. However, the content of cordycepin was highest at 30℃ and less at 20 ℃. The fruiting body also showed a similar tendency: growth was 20 ℃ > 25 ℃ > 30 ℃, but the cordycepin content was 30 ℃ > 25 ℃ > 20 ℃. The content of cordycepin decreased after the fruiting bodies were produced. Next, extraction conditions such as solvent and time were optimized for maximum cordycepin content using response surface methodology (RSM). There was a large difference in the content of cordycepin according to the content of ethanol and the extraction temperature. Through RSM, it was confirmed that the optimum condition for extraction of cordycepin was 48.9 ℃ using 49.0% ethanol, and 160.9 mg/g extract could be obtained under this condition. In conclusion, this study suggested the optimized conditions for the cultivation and extraction of Pupae-Cordyceps for maximizing the content of cordycepin, and this may be applied to the discovery of materials using cordycepin.

• KSBB Journal
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• v.16 no.2
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• pp.207-211
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• 2001

Statistical experimental design methods were employed to select the cultivation factors influencing latic acid production during the fermentation of kitchen refuses. Working volume and pH swings were identified as the main factors affecting lactic acid production. Optimum pH swing was pH 7.8 and working volume was 125 mL in a 250 mL flask. Under optimum condition, lactic acid was produced at 21.8 g/L, which was 6.2 times higher than produced during uncontrolled fermentation.