• KSBB Journal
• /
• v.13 no.2
• /
• pp.187-194
• /
• 1998

For mass production of polyhydroxyalkanoates (PHA), high cell density cultures of Alcaligenes eutrophus by fed-batch culture under phosphate-limitation condition has been investigated. PHA accumulation by the regulation by the regulation of initial phosphate concentration could be automatically induced, and high density cell culture above 200 g/L also could be successfully produced. The production of Poly-$\beta$-hydroxybutyrate (PHB) and dry cell weight increased with increasing the initial phosphate concentration. When the initial concentrations of phosphate were in the ranges of 1.5~4.5 g-PO$_4$/L, PHB and dry cell weight obtained were 83~266 g/L and 61~216 g/L, respectively, and PHB productivity was in the ranges of 1.35~3.10 g/L.h. When a mixture of glucose and propionic acid is used as carbon sources, poly(3-hydroxybutyrate-co-poly-3-hydroxyvalerate), P(3HB-co-3HV), could be also successfully produced under phosphate limitation condition. When the mole ratio of propionic acid to glucose in the feeding solution is 0.22, a final dry cell weight of 150 g/L and a P(3-HB-co-3HV) of 90 g/L were produced. Morphological changes and size distribution of PHB granules synthesized in A. eutrophus under phosphate-limitation condition are determined by TEM during the course of fed-batch. Mean granule diameters of PHB produced are in the range of 0.36~0.39 $\mu$m, and mean cell size was elongated from 0.54~0.59 $\mu$m$\times$ 1.3~1.5 $\mu$m to 0.83~0.89 $\mu$m $\times$2.0~2.3 $\mu$m. Phosphate concentration in media did not affect size distribution of PHB granule and cell.

• Journal of Plant Biotechnology
• /
• v.6 no.4
• /
• pp.265-268
• /
• 2004

Cell growth and ginseng saponin production by large-scale suspension (bioreactor) cultures of Panax ginseng were investigated under various inoculum sizes. Cell growth was low at an inoculum size of 40 g FW/L, and the maximum cell growth was obtained with increasing inoculum size up to 100 g FW/L. The cell density of 333 g FW/L and 12.7 g DW/L was obtained at inoculum size of 100 g FW/L after 30 days of cultivation. Maximum saponin production of $4.40\;\cal{mg/g}$ DW was achieved at 60 g FW/L of inoculum size. Thus, inoculum size 60 g FW/L was suitable for optimum biomass accumulation as well as saponin production during bioreactor cultivation of ginseng suspension cells.

• Korean Journal of Agricultural Science
• /
• v.44 no.4
• /
• pp.604-612
• /
• 2017

In this study, the effects of planting density on the growth of chrysanthemum in a greenhouse were evaluated on two popular varieties (i.e., Sinma and Moonlight). Planting density treatments were as follows: 1) $12cm{\times}12cm$, 2) $6cm{\times}12cm$, 3) $6cm{\times}12cm$ with one-cell vacant, and 4) $6cm{\times}12cm$ with two-cell vacant. Size of each treatments indicate one chrysanthemum was planted in that sized cell that was rectangular shaped field and these treatments were located in a line. Moreover, "one and two-cell vacant" means that it makes middle point of the field empty, offers beside chrysanthemum larger spaces to grow. For the Sinma variety, the results of growth and flowering characteristics at the harvesting stage showed that leaf number, leaf length, flower length, and leaf area were highest when the crop was planted at the $12cm{\times}12cm$ density, and the next preferable density was $6cm{\times}12cm$ with one-cell vacant. For the Moonlight variety, the results showed that stalk height and diameter, leaf number and length, flower length, leaf area, and flower number were highest at the $12cm{\times}12cm$ planting density. For Sinma, ratios of marketable production were 87.5% and 83.3% for the $12cm{\times}12cm$ and $6cm{\times}12cm$ with two-cell vacant, respectively. For Moonlight, ratios were 88.0% and 84.3% for the $12cm{\times}12cm$ and $6cm{\times}12cm$ with two-cell vacant.

• Journal of the Korean institute of surface engineering
• /
• v.37 no.2
• /
• pp.92-98
• /
• 2004

The current efficiency and the microstructure of the trivalent Cr deposits plated in flow cell system were investigated according to additives in sulfate bath and current density. The current efficiency of the deposits plated in the formic acid complexed bath was noticeably higher than that of the deposits from glycine complexed bath. The current efficiency of the deposits from the complexed baths with boric acid buffer increased linearly with current density in the range of 60-100 A/dm$^2$, while that of the deposits from the baths with both Al sulfate and mixed buffers increased parabolically with current density. The nodular crystallite size of the deposits increased with current density, and the deposits plated in low current density region had relatively smooth surface appearance with fine grains. The structure of the deposits from the complexed baths with boric acid buffer changed from amorphous structure to crystalline one with strong (110)peak with increasing current density. The deposits from the baths with both Al sulfate and mixed buffers had generally amorphous structure.

• Journal of Microbiology and Biotechnology
• /
• v.12 no.3
• /
• pp.444-448
• /
• 2002

A $CaCO_3$-alginate beads system was developed for high cell density cultivation of Bifidobacterium longum and the cost-effective media were also screened. In batch process with $CaCO_3$, beads, two strains of B. longum showed both the highest viable cells and optical density in TPY medium, resulting in maximum optical density and viable cell counts of 12.40, $2.22{\times}10^10$ cfu/ml for B. longum ATCC 15707 and 13.71, $3.93{\times}10^10$ cfu/ml for B. longum HLC 3742. Released size distribution, according to $CaCO_3$-alginate bead size preparation, was smaller than others. These results were also examined by observing their morphology. The skim milk-based medium was most adequate to cultivate B. longum as the cheapest medium, and $10\%$ skim milk supplemented with $2\%$ glucose and $1\%$ yeast extract was a suitable medium, supporting the growth to $5.57{\times}10^10$ cfu/ml for ATCC 15707 and $6.82{\times}10^9$ cfu/ml for HLC 3742. During the long-term storage at $4^{\circ}C\;and\;-20{\circ}C$, B. longum cultivated with $CaCO_3$ beads had the highest stability. Consequently, $CaCO_3$-alginate beads buffer was found to be useful not only to cultivate B. longum but also to preserve cultures.

• Macromolecular Research
• /
• v.11 no.2
• /
• pp.104-109
• /
• 2003

A microcellular, which combines a rubber with the conventional formulation of styrene/divinylbenzene/sorbitan monooleate/water system, was prepared using high internal phase emulsion (HIPE) polymerization. Although the open microcellular foam with low density from the conventional HIPE polymerization shows highly porous characteristics with fine, regular and isotropic structure, the one having much smaller cell size is desirable for various applications. In this study, a polybutadiene was introduced to reduce the cell size with comparable properties. Major interests were focused on the effects of rubber concentration and agitation speed on the cell sizes and compression properties. Scanning electron microscopy was used to observe the microcellular morphology and compression tests were conducted to evaluate the stress-strain behaviors. It was found that the cell size decreased as rubber concentration increased, reflecting a competition between the higher viscosity of continuous phase and the lower viscosity ratio of dispersed to continuous phases due to the addition of high molecular weight rubber into the oil phase of emulsion. A correlation for the average cell size depending on agitation speed was attempted and the result was quite satisfactory.

• Journal of the Korean Society for Marine Environment & Energy
• /
• v.12 no.2
• /
• pp.91-95
• /
• 2009

To understand the effect of attachment substrate on the growth of benthic microalgae, we experimentally investigated the growth of benthic microalgae Nitzschia sp. (Jinhae Bay strain) with additions of glass beads in different sizes. The glass beads used in this study are 0.09-0.15 mm (G1), 0.25-0.50 mm (G2), 0.75-1.00 mm (G3) and 1.25-1.65 mm (G4). No addition of glass beads used as controls. Highest specific growth rate (0.37/day) and maximum cell density ($9,232{\pm}840$ cells/mL) of Nitzschia sp. showed at the smallest glass beads (G1), and the specific growth rate and maximum cell density were decreasing with increasing size of glass beads (specific growth rate and maximum cell density of G4 was 0.24/day and $6,397{\pm}524$ cells/mL, respectively). Moreover, specific growth rate of the control experiment (0.23/day) was significantly lower than their of G1 to G3 experiment. The results indicated that the attachment substrate for benthic microalgae as Nitzschia sp. is important factor which affecting the growth rate as well as cell density. Therefore, the physiological experiment of benthic microalgae seems to be necessary to preliminary experiment, which is addition or not of the attachment suitable substrate and the grain size for the target species of benthic microalgae.

• Elastomers and Composites
• /
• v.36 no.1
• /
• pp.52-60
• /
• 2001

Physical properties of foams depend on the density of foams, Physical properties of base polymers, open ceil contents, and cell structures including the size, size distribution, shape of ceil and the thickness of membrane and strut. The density of foam is affected by raw materials, concentration oi crosslinking agent and blowing agent and process parameters such as processing technique and condition. Ethylene vinyl acetate copolymer(EVA) foam is a crosslinked cellular material. The foaming characteristics and physical properties of EVA foam are affected by decomposition rate of blowing agent. In this study, the decomposition rate of blowing agent and crosslinking rate, foaming characteristics and physical properties of foams were evaluated. The slow decomposition rate of blowing agent results in low density foam, good shock absorption property and uniform cell size distribution compared to the high decomposition rate of blowing agent.

• Journal of Plant Biology
• /
• v.28 no.2
• /
• pp.141-148
• /
• 1985

The effects of sizes and densities of cells cultured, conditioned medium, and media pH on the somatic embryogenesis of carrot (Daucus carota L.) were examined. A large number of globular embryoids was formed after 4 days in cell culture, and later globular embryoids developed into heart and torpedo shape. High cell density resulted in higher number and better growth of embryos, especially on conditioned medium than Murashige-Skoog medium. The fresh weight and number of embryoids formed increased with the decrease in cell size. The significant reduction in fresh weight and number of embryoids was obtained when culturing cells with diameter of over 90 ${\mu}{\textrm}{m}$. Dry weight and number of embryoids were markedly reduced with medium pH of 4 or 7, but promoted with pH 6.0.

• Journal of Life Science
• /
• v.6 no.2
• /
• pp.94-103
• /
• 1996

To understand effect of inoculum size, cell density, sucrose concentration and concentrations of MS basal on suspension culture and protoplast isolation of wild viola(Viola patrinii DC.) callus from petiole segments this experiment was conducted. In the lot of 30 mesh inoculum size, two observations were; One was that a considerable increase in the fresh and dry weight of callus was determined. Another was that the callus mass was relatively compact compared with others. A recommendable cell density was 0.4g for 20ml culture medium and the higher sucrose concentration, the higher fresh and dry weight were obtained. The dilution of MS basal salt was differently affected on fresh and dry weight; the highest fresh weight was found in 1x MS salt, while the higest dry weight was in 1/3x dilution.The addition of casein hydrolysate(3g/L) was more effective to increase of both fresh and dry weight. THe contents of protein was great in the inoculum lots with larger inoculum sizeand higher concentration of MS basal salts contenting 3g/L of casein hydrolysate and higher sucrose compared with others. The greatest protoplasts were isolated from the lot of 10 mesh size treated with 1%pectinase SE-150 and 2% cellulase YC. In general, for optimal protoplast isolation the followingconditions were recommended; 1) Use of smaller cell size cultured for 2-5 weeks, and 2) more than 5 hours incubation using the combined mixture of the enzymes with proper concentrations.