• Korean Journal of Food Science and Technology
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• v.30 no.2
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• pp.425-433
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• 1998

The characteristics of the reaction of calcium carbonate $(CaCO_3)$ immobilized with alginate as buffer system for the high concentration cultivation of bifidobacteria in fermenter are described by the mathematical model, and tested for the reusing possibility of the used $CaCO_3$ beads. When$CaCO_3$ beads with the various diameters were reacted in 0.1 M of the mixed organic acids (0.6 M of acetic acid and 0.4 M lactic acid) and in fermenter inoculated Bifidobacterium longum ATCC 15707, the change of bead diameters can be calculated with the amount of the decreased $CaCO_3$ from the surface of bead using the mathematical model. These values was similar to the directly measured bead diameter by a micrometer. Therefore, it was considered that the mathematical model could be used for explaining the reaction charateristics of the $CaCO_3$ bead reacted with the organic acids. When Bifidobacterium longum was incubated at $37^{\circ}C$ for 20 hours in fermenter with $CaCO_3$ beads, the buffering effect of $CaCO_3$, the reduce rate of the bead diameter, and the growth rate of Bifidobacterium longum were higher at the smaller beads than beads with the larger diameters. Also, when Bifidobacterium longum was incubated in fermenter with the mixed beads which were added new beads to the recovered beads in order to equalize with the total surface area of initial beads, the buffering effect of $CaCO_3$ bead and the growth rate of Bifidobacterium longum were very corresponded with the results of the fermentation using the only initial beads. Therfore, it is expected that the used beads can be reused by adding the initial beads.

• Food Engineering Progress
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• v.14 no.3
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• pp.208-216
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• 2010

Lab scale experiments were conducted in order to assess the applicability of $CaCO_{3}$-alginate beads as neutralizer for the high cell density cultivation and prepare the direct vat inoculation cultures of isolated sourdough lactic acid bacteria. With increasing the amount of bead and decreasing the diameter of bead in acidic solution, the neutralizing effect of $CaCO_{3}$-alginate bead became higher. In batch process with $CaCO_{3}$-alginate beads, Lactobacillus amylovorus DU-21 isolated from sourdough showed the highest viable cell counts and optical density in MRS broth. The values of viable cell counts and optical density were 9.996 log CFU/mL and 3.97, respectively. Experiments on the conditions which increase viability during lyophilization were carried out and the following results were obtained; 15% glycerol revealed the high cryoprotective effect on the concentrated cultures during lyophilization among the two cryoprotective agents. Consequently, $CaCO_{3}$-alginate beads and 15% glycerol were found to be useful not only to cultivate Lactobacillus amylovorus DU-21 but also to preserve strain.

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

• 한국생물공학회:학술대회논문집
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• 2000.04a
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• pp.203-206
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• 2000

Calcium carbonate $(CaCO_3)$ bead immobilized with alginate were developed as buffer system to enhance the cultivation efficiency of bifidobacteria. When Bifidobacteriuim longum KCTC 3128 and HLC 3742 were independently cultivated in 2.5-liter fermenter buffered the $CaCO_3$ bead, NaOH, $Na_2CO_3$, and $NH_4OH$. The proliferation of bifidobacteria and their storage stability were higher in culture broth buffered $CaCO_3$ beads than in culture broth buffered with NaOH, $Na_2CO_3$, and $NH_4OH$. Therefore, $CaCO_3$ bead may be useful as a buffer to enhance of the cultivation efficiency and viability of bifidobacteria.

• Korean Journal of Food Science and Technology
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• v.29 no.1
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• pp.126-132
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• 1997

Calcium carbonate ($CaCO_3$) immobilized with alginate was studied as buffer system to enhance the cultivation efficiency of Bifidobacterium longum (ATCC 15707) which is inhibited at low pH. To test the bufferring effect of the immobilized $CaCO_3$ beads, pH value in each modified trypticase-proteose peptone-yeast (TPY) broth which is adjusted to pH 4.0 with acetic acid, lactic acid and complex solution of acetic and lactic acid, 3:2 (M:M) was tested by concentration of $CaCO_3$ bead and reaction time. The bufferring effect of $CaCO_3$ bead became higher with increasing the amount of $CaCO_3$ bead in the acidic solution. The growth rate of bifidobacteria and bufferring effect were examined in relation to the amount of $CaCO_3$ bead and concentration of glucose in the modified TPY media. The growth rate of bifidobacteria and bufferring effect were increased with increasing the amount of $CaCO_3$ bead and concentration of glucose. Also, the exponential time of bifidobacteria became longer with increasing the amount of $CaCO_3$ bead and concentration of glucose in the modified TPY media. When we observed the growth rate of bifidobacteria by the method of pH-controlled culture and $CaCO_3$ buffer system, the $CaCO_3$ buffer system was more effective than that of pH-controlled culture. Therefore, this $CaCO_3$ buffer system may be useful as a method to enhance of the cultivation efficiency of bifidobacteria.

• Conservation Science in Museum
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• v.30
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• pp.71-88
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• 2023

This paper examined the visible characteristics and chemical composition of glass beads from the Joseon Dynasty as well as the associations thereof. It also explored the characteristics and uses of glass beads by region. This study covered a total of 1,819 pieces excavated from 25 locations in the Gyeonggi, Chungcheong, and Gyeongsang regions, of which 537 pieces were analyzed for their chemical composition. Glass beads of the Joseon Dynasty take a variety of shapes such as a Round, Coil, Floral, Segmented, Flat, Oval, and Calabash. Colors vary from shades of brown (brown, lemon yellow) and shades of blue (Bluish-Green, greenish-Blue, Purple-Blue) to shades of white (colorless, white) and shades of green (Green, Greenish-Blue, Greenish-Brown). Brown accounts for the largest percentage, followed by Bluish-Green, greenish-Blue. It was identified that Drawing technique was the most common glass bead production technique of the Joseon Dynasty. Potassium oxide (K₂O) was the most common flux agent for glass beads, while the potash glass and mixed alkali glass groups account for the largest quantity. The choice of stabilizers depended on the type of flux agents used, but the most common were calcium oxide (CaO) and aluminum oxide (Al₂O₃). The potash glass and potash lead glass groups are high in CaO and low in Al₂O₃, the mixed alkali glass group is high in CaO, and the lead glass group is low in CaO. In terms of the association between color and shape, most of the beads with shade of brown and blue have round shapes of brown and blue have spherical shapes, while the coil shape is prominent in blue beads. A high percentage of green and colorless beads also take the shape of a coil, while white beads in general have a floral shape. In terms of the association between shape and chemical composition, round, floral and segmented shapes account for a high percentage of the potash glass group, while coil and flat shapes are common in the mixed alkali glass group. This paper also analyzed the colorants for each color based on the association between color and chemical composition. Iron (Fe) was used as the colorant for brown and white, and titanium (Ti) and iron were used for light yellow. Purple-Blue was produced by by cobalt (Co), and greenish-Blue, Bluish-Green, green, Greenish-Blue were produced by iron and copper (Cu). Colorless beads had a generally low colorant content.

• Journal of the Korean Society of Food Science and Nutrition
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• v.24 no.5
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• pp.803-810
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• 1995

Co-immobilized mixed culture system(A-Z system) composed of two different oxygen-demanding strains, aerobic(Aspergillus awamori) and anaerobic(Zymomonas mobilis) strains, in a Ca-alginate gel beads was developed to increase ethanol production from raw starch as a carbon source. Optimal mixture ratio of A. awamori and Z. mobilis was $1.25{\times}10^{9}\;spores/L-gel$ and 0.5g cells/L-gel, respectively. After 120 hours of cultivation, gel beads distinguished oxygen-rich surface for A. awamori from oxygen-deficient central part for Z. mobilis. At A-Z culture system, yield of ethanol on glucose, $Y_{p/s}=0.18$, was very low and there was high leakage of cells from surface of gel beads. At A-Z 36 cultrue system with changing silicon check valve for cotton plug at 36 hours in A-Z culture system, there was no cell leakage from gel beads, pH was maintained at around 4.3 during cultivation, and yield of ethanol on glucose, $Y_{p/s}=0.36$, showed 2 times higher than that of control culture system(cotton plug culture).

• Korean Journal of Chemical Engineering
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• v.35 no.12
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• pp.2384-2393
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• 2018

Porous alginate-based hydrogel beads (porous ABH) have been prepared through a facile and sustainable template-assisted method using nano-calcium carbonate and nano-$CaCO_3$ as pore-directing agent for the efficient capture of methylene blue (MB). The materials were characterized by various techniques. The sorption capacities of ABH towards MB were compared with pure sodium alginate (ABH-1:0) in batch and fixed-bed column adsorption studies. The obtained adsorbent (ABH-1:3) has a higher BET surface area and a smaller average pore diameter. The maximum adsorption capacity of ABH-1:3 obtained from Langmuir model was as high as $1,426.0mg\;g^{-1}$. The kinetics strictly followed pseudo-second order rate equation and the adsorption reaction was effectively facilitated, approximately 50 minutes to achieve adsorption equilibrium, which was significantly shorter than that of ABH-1:0. The thermodynamic parameters revealed that the adsorption was spontaneous and exothermic. Thomas model fitted well with the breakthrough curves and could describe the dynamic behavior of the column. More significantly, the uptake capacity of ABH-1:3 was still higher than 75% of the maximum adsorption capacity even after ten cycles, indicating that this novel adsorbent can be a promising adsorptive material for removal of MB from aqueous solution under batch and continuous systems.

• Microbiology and Biotechnology Letters
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• v.44 no.4
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• pp.504-511
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• 2016

Lactulose, a synthetic disaccharide, has received increasing interest because of its role as a prebiotic that can increase the proliferation of Bifidobacterium and Lactobacillus spp. and enhance the absorption of calcium and magnesium. While the industrial production of lactulose is still mainly achieved by the chemical isomerization of lactose in alkaline media, this process has drawbacks including the need to remove catalysts and by-products, as well as high energy requirements. Recently, the use of cellobiose 2-epimerase (CE) has been considered an interesting alternative for industrial lactulose production. In this study, to develop a process for enzymatic lactulose production using CE, we screened improved mutant enzymes ($CS-H^RC^E$) from a library generated by an error-prone PCR technique. The thermostability of one mutant was enhanced, conferring stability up to $75^{\circ}C$, and its lactulose conversion yield was increased by 1.3-fold compared with that of wild-type CE. Using a recombinant Escherichia coli strain harboring a CS35 $H^RC^E$-expressing plasmid, we prepared cell beads immobilized on a Ca-alginate substrate and optimized their reaction conditions. In a batch reaction with 200 g/l lactose solution and the immobilized cell beads, lactose was converted into lactulose with a conversion yield of 43% in 2 h. In a repeated 38-plex batch reaction, the immobilized cell beads were relatively stable, and 80% of the original enzyme activity was retained after 4 cycles. In conclusion, we developed a reasonable method for lactulose production by immobilizing cells expressing thermostable CE. Further development is required to apply this approach at an industrial scale.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.32 no.2
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• pp.186-191
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• 1999

The three speices of miroalgae (Chlorella vulgaris, Dunaliella salina and Porphyridium purpureum) were immobilized in Ca-alginate capsules as a basic study for development of economic cultivation process, and then were cultivated in an air-bubble column bioreactor. Under the batch culture of aerobic conditions, the thickness of the capsule membrane and $CO_2$ supply did not affect the growth of the immobilized microalga, Chlorella vulgaris. Cell concentration of immobilized microalgae in the capsule was higher than those of imobilized microalgae in beads and free cells. The cell concentration of microencapsulated Dunaliella salina was greater about 5 times than that of free cells. Based on these results, it is concluded that the application of microencapsulation technology to the culture of microalgae was an effective method for high-density cultivation.