• Bulletin of the Korean Chemical Society
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• v.29 no.1
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• pp.168-172
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• 2008

A microbial fuel cell is a noble green technology generating electricity from biomass and is expected to find applications in a real world. One of main hurdles to this purpose is the low power density. In this study, we constructed a prototype microbial fuel cell using Proteus vulgaris to study the effect of various reaction conditions on the performance. Main focus has been made on the modification of the anode with electropolymerized polypyrrole (Ppy). A dramatic power enhancement was resulted from the Ppy deposition onto the reticulated vitreous carbon (RVC) electrode. Our obtained maximum power density of 1.2 mW cm-3 is the highest value among the reported ones for the similar system. Further power enhancement was possible by increasing the ionic strength of the solution to decrease internal resistance of the cell. Other variables such as the deposition time, kinds of mediators, and amount of bacteria have also been examined.

• Bulletin of the Korean Chemical Society
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• v.29 no.7
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• pp.1344-1348
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• 2008

A microbial fuel cell (MFC) has been regarded as noble clean energy technology that can directly convert biomass to electricity. However, its low power density is a main limitation to be used as a new energy source. To overcome this limitation, we focused on the anode improvement in a mediator-type MFC using P. vulgaris as a biocatalyst. Fuel cell performance increased when the anode was coated with carbon black or polypyrrole. The best performance was observed when polypyrrole/carbon black (Ppy/CB) composite material was coated on a carbon paper electrode. Our obtained value of 452 mW $m^{-2}$ is the highest value among the reported ones for the similar system. The effects of amount of Ppy/CB, mediator concentration, and amount of P. vulgaris have also been examined.

• KSBB Journal
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• v.24 no.2
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• pp.177-181
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• 2009

This study was initiated to investigate the impacts of media types and other components on the callogenensis and cell mass production of Panax vietnamensis in the first step of the cell biomass procedure. Four media were checked: Murashige-Skoog (MS), White, Gamborg and Nitch-AII. All the four media were shown potential media for Panax vietnamensis callogenensis and cell mass production, in which the MS medium showed the best results: the successful callogenensis ratio and cell mass formation were 30% and 62,93 ${\pm}$ 3,63 mg (DW) respectively, the Nitch medium showed the lowest results: the successful callogenensis ratio and cell mass formation were 15% and 27,10 ${\pm}$ 2,24 mg (DW) respectively. The results showed that the MS medium is the most suitable medium for Panax vietnamensis callogenensis and cell mass production.

• Journal of the Korean Society of Manufacturing Process Engineers
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• v.20 no.8
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• pp.33-41
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• 2021

Recently, many studies have been conducted on substituting fossil fuels with bio-refineries in existing industrial systems using biomass. Among the various bio-refineries, microalgae have received wide attention because it uses inorganic compounds to produce useful substances, which are extracted by a cell disruption process. Although numerous cell disruption methods exist, cell disruption efficiency has been studied by ultrasonic treatment. Ultrasound is a high-frequency (20 kHz or higher) sound wave and causes cell disruption by cavitation when passing through a solvent. In this study, we used the microalgal species Chlorella sp., which was cultured in a plate-type photobioreactor. The experiment was conducted using a continuous low-frequency processing device. The reduction of cells with time due to cell disruption was fitted using a logistic model, and optimum conditions for highly efficient cell disruption were determined by conducting experiments under multiple conditions.

• KSBB Journal
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• v.5 no.1
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• pp.37-42
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• 1990

In on-line measurement, there were two difficult problems to remove the biomass in the sample and to prevent the contamination at the sampling. In this study, the problem of the contamination at the sampling was solved by using the sampling device consisting of sterilizable sampling line, peristaltic pump and three-way valve. The glucose concentration was measured by glucose calibration equation without removing the biomass. Xanthan fermentation was performed satisfactorily using this automatic analyzing device.

• Journal of Industrial and Engineering Chemistry
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• v.68
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• pp.257-266
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• 2018

Here, a controlled green synthesis route involving hydrothermal pre-carbonization cum pyrolysis is reported that converts cucumber into graphene-like carbon nanosheets for supercapacitor application. Transmission electron microscopy analysis reveals the formation of ultra-thin carbon nanosheets with distributed pores. This cucumber derived carbon exhibits high specific capacitance of $143F\;g^{-1}$ in aqueous electrolyte. The two-electrode symmetric cell exhibits a specific capacitance of $58F\;g^{-1}$ at high current density, and high capacitance retention of 97% after 1000 cycles. This simple low-cost process involving widely available cucumber as biomass precursor is a promising, commercially viable approach for developing high-performance supercapacitors.

• Journal of Microbiology and Biotechnology
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• v.32 no.5
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• pp.663-671
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• 2022

The saccharification of cellulose and hemicellulose is essential for utilizing lignocellulosic biomass as a biofuel. While cellulose is composed of glucose only, hemicelluloses are composed of diverse sugars such as xylose, arabinose, glucose, and galactose. Sulfolobus acidocaldarius is a good potential candidate for biofuel production using hemicellulose as this archaeon simultaneously utilizes various sugars. However, S. acidocaldarius has to be manipulated because the enzyme that breaks down hemicellulose is not present in this species. Here, we engineered S. acidocaldarius to utilize xylan as a carbon source by introducing xylanase and β-xylosidase. Heterologous expression of β-xylosidase enhanced the organism's degradability and utilization of xylooligosaccharides (XOS), but the mutant still failed to grow when xylan was provided as a carbon source. S. acidocaldarius exhibited the ability to degrade xylan into XOS when xylanase was introduced, but no further degradation proceeded after this sole reaction. Following cell growth and enzyme reaction, S. acidocaldarius successfully utilized xylan in the synergy between xylanase and β-xylosidase.

• Biotechnology and Bioprocess Engineering:BBE
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• v.9 no.1
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• pp.41-46
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• 2004

The influence of various culture conditions on growth and ginkgolides (GKA and GKB), and bilobalide formation in callus and suspension cultures of Ginkgo biloba were investigated. Callus induced from the leaf petioles exhibited distinct morphological and physiological responses. The cell biomass and ginkgolides content varied among the cell lines; brownish callus lines produced high levels of ginkgolides and bilobalide in spite of poor cell growth. Among the culture media used, MS medium showed significant effect on cell growth and ginkgolides production. Low concentration of sucrose (3%) improved cell growth, while higher sucrose levels (5 and 7%) improved ginkgolides production. Cultivation of callus cultures above 28$^{\circ}C$ dramatically reduced their growth rate; however the cell lines grown at 36$^{\circ}C$ showed increased levels of bilobalide content. A 2.5-L balloon type bubble bioreactor (BTBB) was successfully developed for the cell growth and ginkgolides production.

• Korean Journal of Medicinal Crop Science
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• v.12 no.5
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• pp.366-371
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• 2004

Aconitine alkaloids produced from cell suspension cultures of Aconitum napellus for the first time. The effects of various culture conditions on cell biomass and aconitine accumulation in cell suspension cultures were investigated. Suspension cell cultures of A. napellus were established by transferring callus tissues from leaf explants onto liquid MS medium supplemented with $1\;mg/l$ NAA and $0.1\;mg/l$ kinetin. Among the culture media tested, MS medium had a pronounced effect on cell growth and aconitine accumulation. The maximum dry cell weight was obtained at inoculum size of 3 g (FCW) per flask and in MS medium supplemented with 5% sucrose after 8 weeks. The addition of salicylic acid (SA) and yeast extract (YE) in the MS medium enhanced aconitine accumulation. Using a proper combination of culture condition and supplements, aconitine content could reach 0.043% (dry weight basis), that was $2.5{\sim}3$ fold higher that detected in control cultures.

• Journal of Bio-Environment Control
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• v.23 no.2
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• pp.71-76
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• 2014

There have not been many studies conducted on the seedling production, especially in plug trays, of traditional medicinal plant species. In an effort to establish guide lines for seedling production, this study investigated the effect of plug cell size on the growth and development of plug seedling of three medicinal plant species. Seeds were sown in either 128, 200, or 288-cell plug trays, containing a commercial medium. Growth and development of individual seedling was generally promoted with increasing size of a plug cell in all of the three species. The greatest biomass of the seedlings gained in a plug tray was obtained in the 288-cell trays in Perilla frutescens var. acuta Kudo and Sophora tonkinensis, and the 200-cell trays in Angelica gigas Nakai. Overall growth and development of the shoot and root of a single seedling of Perilla frutescens var. acuta Kudo, except total chlorophyll and anthocyanin contents, was the greatest in the 128-cell tray. However, length of the longest root, length, width and area of the leaf, internode length, root fresh weight, and root ball formation in the 200- and 288-cell trays were not significantly different each other. In Sophora tonkinensis, although length of the longest root, stem diameter, leaf width, leaf area, shoot fresh weight, and root ball formation were not significantly different among the treatments, length of the longest root and root ball formation of a single seedling were the greatest in the 128-cell tray. Overall shoot and root growth, except total chlorophyll content, of a single seedling of Angelica gigas Nakai was the greatest in the 128-cell tray. Based on the total biomass, it is concluded that 288-cell trays are recommended for production of plug seedlings of medicinal plant species P. frutescens var. acuta Kudo and S. tonkinensis. In A. gigas Nakai, it would be more economical to use the 200-cell trays than 128-cell trays due to total biomass.